EP Patent Validation Service

PATENTS, Uncategorized Comments Off

Sep 062019

Traditional route

The conventional route for EP patent validation is for the client to instruct their EP attorneys to execute the validation. The EP attorneys would then instruct a validations provider (like us) or perform the validations themselves using attorney partners in each country who they use based on a reciprocity model, which is usually not cost or quality selective. The EP attorneys would add significant fees for each country.

About our EP Patent Validation service : Why you should go with us.

Benefits of using our EP validation service :

By using a centralised validations provider like us, the client is cutting out one extra layer of cost, which is usually the most significant cost layer. All large patent filers in Europe use a centralised provider like our associate company because of benefits like the following:

Reduced Risk

We with our European team are specialists in European Patent Validation, which means there is a significantly reduced risk of misunderstanding, unexpected costs, or of course the unthinkable risk of accidental loss of a patent due to the complex and constantly changing regulations around Europe.

Reduced Cost

Validation is a significant part of the cost of a European Patent lifecycle, especially if many countries are required. Filing tens of thousands of validations per year, and translating millions of words into every language, means that ours buying power is enormous. We provide user-friendly and extremely efficient processes to our agents and suppliers which further reduce their costs, and all of this means we are able to pass on these savings to our customers.

We expect to able to reduce most client’s validations costs by at least 50%

Sandeep Mishra

Director at De Science Infoware Pvt Ltd

linkedin.com/in/sandeep-mishra-35b215b

scienceinfoware@gmail.com

///////////Sandeep Mishra, Director, e Science Infoware, ep, patent

SOFOSBUVIR, NEW PATENT, WO 2018032356, Pharmaresources (Shanghai) Co Ltd

PATENTS, Uncategorized Comments Off

Mar 142018

Image result for PHARMARESOURCES (SHANGHAI) CO., LTD

SOFOSBUVIR, NEW PATENT, WO 2018032356, Pharmaresources (Shanghai) Co Ltd

WO-2018032356, Pharmaresources (Shanghai) Co Ltd

CHEN, Ping; (CN).
PENG, Shaoping; (CN).
LI, Yinqiang; (CN).
LI, Dafeng; (CN).
DONG, Xuejun; (CN)

Process for the preparation of lactone derivatives and their intermediates are important precursors for the synthesis of anti-hepatitis C virus agents, including sofosbuvir . Represents a first filing from Pharmaresources (Shanghai) Co Ltd and the inventors on this API. Gilead Sciences , following its acquisition of Pharmasset , has developed and launched sofosbuvir, a pure chiral isomer of PSI-7851, a next-generation HCV uracil nucleotide analog polymerase inhibitor prodrug for once-daily oral use.

Hepatitis C virus (HCV) infection represents a global health thereat in need of more effective treatment options. The World Health Organization (WHO) estimates that 130-170 million of individuals worldwide have detectable antibodies to HCV and approximately 60-85％of this population develops into chronic disease, leading to liver cirrhosis (5-25％) and hepatocellular carcinoma (1-3％) and liver failure. While there were existing therapeutics including pegylated interferon- (Peg-IFN) and ribavirin (RBV) , they are suboptimal due to various adverse effects, intolerability, low efficacy and slow response in reducing the viral loads across the multiple genotypes (1-6) of HCV. Therefore, there is an urgent and enormous need to develop more effective and efficacious novel anti-HCV therapies.

During the past decade, there have been a variety of small molecule agents as direct-acting antivirals (DAAs) targeting HCV viral replication via action on both structural and nonstructural proteins (NS3-5) have been launched inmarket or in late-stage clinical development. Among the DAAs reported, Soforsbuvir (brand name Sovaldi) targeting NS5B protein from Gilead was approved by FDA in 2003 for HCV genotypes 2 and 3 (in combination with Ribavin) . In 2014, a combination of Sofosbuvir with viral NS5A inhibitor Ledipasvir (brand name Harvoni) was approved. This combination provides high cure rates in people infected with HCV genotype 1, the most common subtype in the US, Japan, and much of the Europe, without the use of interferon, and irrespective of prior treatment failure or the presence of cirrhosis. Compared to previous treatment, Sofosbuvir-based regimens provide a higher cure rate, fewer side effects, and a 2-4 fold reduced duration of therapy.

Sofosbuvir is a prodrug using the ProTide biotechnology strategy. It is metabolized to the active antiviral agent 2′-deoxy-2′-α-fluoro-β-C-methyluridine-5′-triphosphate. The triphosphate serves as a defective substrate for the NS5B protein, which is the viral RNA polymerase, thus acts as an inhibitor of viral RNA synthesis.

Due to the tremendous success in Sorosbuvir-based oral therapy, there remains a need for a more efficient method for making sofosbuvir-like anti-hepatitis C virus agents, including sofosbuvir and intermediates thereof. A variety of methods describing different synthetic approaches for substituted lactone (VI) shown below, a key intermediate for Sofosbuvir and its like anti-viral drugs have been published.

WO2008045419 reported a seven-step synthesis (Scheme 1) for the γ-lactone intermediate. When chiral glyceraldehyde used as the starting material, two new chiral centers were generated following Witting reaction and dihydoxylation. After cyclic sulfonate formed, the fluoro subsititution was introduced stereospecifically by a SN2 reaction with HF-Et3N. Lactonization was achieved under the acid conditions followed by hydroxy protecting step to give the desired intermediate. The main disadvantage of this approach is that considerable quantities of both solid and acidic liquid wastes were produced during the process which is very difficult to handle with (e.x. filtration) and/or contributes to the enviroment pollution upon disposal.

Scheme 1

In a similar process reported in CN105418547A (Scheme 2) , the Witting product was epoxidized followed by ring-opening fluorolation by HF-Et₃N or other fluoro-containing reagents, significant amount of regioisomer was observed which was difficult to remove from the oily mixture.

Scheme 2

US20080145901 reported an enzymetic approach to the γ-lactone intermediate (scheme 3) . Treatment of ethyl 2-fluoro-propinate with chiral glyceraldehyde to form the aldol adducts consisting the mixture of four disteroisomers. The disteroisomers were selectively hydrolyzed by enzyme and the major isomer was obtained. After lactonization and hydroxyl protecting, other two isomers were removed by recrystallization.

WO2008090046 reported a similar synthesis as described in Scheme 3.2-fluoro-propionic acid was converted to diffirent bulky ester or amide and reacted with chiral glyceraldehydes. The mixture of the disteroisomers were purified by recrystallization to obtain the pure isomer. By using the method described in Scheme 3, the γ-lactone can be scale up to kilogram quantities but the de value of the final product can not achieve desired level.

Scheme 3

In WO2014108525, WO2014056442 and CN105111169, diffirent auxiliaries were used in the Aldol Reaction to improve the disteroisomeric selectivity (Scheme 4) . The process was shortened to 3～4 steps and the de value was increase significantly.

Scheme 4

Examples

Example 1： preparation of 2-fluoropropanoyl chloride (3)

Chlorosulfonic acid (660 mL, 10 mol, 20 eq) was added to a solution of phthaloyl dichloride (1.4 L, 10 mol, 20 eq) and ethyl-2-fluoropropanoate (600 g, 5 mol) at room temperature. The solution was heated at 120 ℃ for 4 hs. 2- (R) -fluoropropanoyl chloride was distilled from the reaction mixture under reduced pressure and recovered as a colourless oil (320 g, 58.2％) . ¹H-NMR (CDCl₃， 400 MHz) ： δ 5.08 (dq, J ＝ 48.8, 6.8 Hz, 1 H) , 1.63 (dd, J ＝22.8, 6.8 Hz, 3 H) .

Example 2： preparation of (4R) -3- (2-fluoropropanoyl) -4-isopropyloxazolidin-2-one (4)

n-Butyl lithium (2.5 M in hexane, 30 mL, 75 mmol, 1.1 eq) was added to a solution of 4-(R) -4-isopropyl-2-oxazolidinone (8.8 g, 68.2 mmol, 1 eq) in dry THF (80 mL) at -50 ℃ under N₂ atomosphere. After 30 min, 2-fuoropropanoyl chloride (6.8 mL, 0.9 eq) was added, and the solution was stirred for 4 hs at -50 ℃. The reaction was then quenched with a saturated solution of NH₄Cl (50 mL) , extracted with MTBE (80 mL *2) , washed with brine and dried over MgSO₄. Solvents were removed under reduced pressure. The product was purified over silica (Hexane/EtOAc＝ 10/1) and recovered as a brown oil (9 g, 74.8％) . ¹H-NMR (CDCl₃, 400 MHz) : δ 6.00 (dm, J ＝ 49.2Hz, 1 H) , 4.27 -4.53 (m, 3 H) , 2.43 (dm, J ＝ 52.6 Hz, 1 H) , 1.63 (td, J ＝ 23.2Hz, 3 H) , 0.92 (dq, J ＝ 17.8 Hz, 6 H) .

[0206]

Example 3： preparation of (4S) -3- (2-fluoropropanoyl) -4-isopropyloxazolidin-2-one (5)

[0207]

n-Butyl lithium (2.5 M in hexane, 75 mL, 187 mmol, 1.1eq) was added to a solution of 4- (S) -4-isopropyl-2-oxazolidinone (22 g, 170 mmol, 1 eq) in dry THF (200 mL) at -50 ℃ under N₂ atomosphere. After 30 min 2-fuoropropanoyl chloride (17 mL, 153 mmol, 0.9 eq) was added, and the solution was stirred for 1 h at -50 ℃. After the starting material was completely consumed, the reaction was then quenched with a saturated solution of NH₄Cl (125 mL) , extracted with MTBE (200 mL *2) , washed with brine and dried over MgSO₄. Solvents were removed under reduced pressure. The product was purified over silica (hexane/EtOAc＝ 10/1) and recovered as a brown oil (34 g, 83.3％) . ¹H-NMR (CDCl₃, 400 MHz) : δ 5.93 (dm， J ＝ 48.8 Hz, 1 H) , 4.19 -4.17 (m, 3H) , 2.35 (dm, J ＝ 52.8 Hz , 1 H) , 1.55 (td, J ＝ 23.6 Hz, 3 H) , 0.85 (dq, J ＝ 18 Hz, 6 H) .

Example 4： preparation of (4R) -3- (2-fluoropropanoyl) -4-phenyloxazolidin-2-one (6)

n-Butyl lithium (2.5 M in hexane, 13.5 mL, 33.74 mmol, 1.1 eq) was added to a solution of (R) -4-phenyloxazolidin-2-one (5 g, 30.67 mmol, 1 eq) in dry THF (75 mL) at -50 ℃ under N₂ atomosphere. After 30 minutes, 2-fuoropropanoyl chloride (3.75 g, 33.74 mmol) was added, and the solution was stirred for 1 h at -50 ℃ to -60 ℃. The reaction was then quenched with a saturated solution of NH₄Cl, extracted with EtOAc, washed with NaHCO₃(sat) , brine and dried over MgSO₄. Solvents were removed under reduced pressure. The product was purified over silica (hexane /EtOAc) and recovered as a brown oil (4 g, 55％) . ¹H-NMR (CDCl₃, 400 MHz) : δ 7.35-7.21 (m, 5 H) , 5.99-5.84 (md, 1 H) , 5.42-5.33 (dd, 1 H) , 4.72 (dd, 1 H) , 4.31 (m, 1 H) , 1.50 (m, 3 H) .

Example 5： preparation of (4s) -3- (2-fluoropropanoyl) -4-phenyloxazolidin-2-one (7)

n-Butyl lithium (2.5 M in hexane, 67.5 mL, 169 mmol, 1.1 eq) was added to a solution of (s) -4-phenyloxazolidin-2-one (25 g, 153 mmol, 1 eq) in dry THF (375 mL) at -60 ℃ under N₂ atomosphere. After 30 min, 2-fuoropropanoyl chloride (18.7 g, 169 mmol) was added, and the solution was stirred for 1h at -50 ℃ to -60 ℃. The reaction was then quenched with a saturated solution of NH₄Cl, extracted with EtOAc, washed with NaHCO₃ (sat) , brine and dried over MgSO₄. Solvents were removed under reduced pressure. The product was purified over silica (hexane /EtOAc) and recovered as a brown oil (16.5 g, 45.4％) . ¹H-NMR (CDCl₃, 400 MHz) : δ 7.36-7.20 (m, 5 H) , 5.95-5.80 (md, 1 H) , 5.42-5.30 (dd, 1 H) , 4.71 (dd, 1 H) , 4.30 (m, 1 H) , 1.51 (m, 3 H) .

Example 6： preparation of (4S) -4-benzyl-3- (2-fluoropropanoyl) oxazolidin-2-one (8)

n-Butyl lithium (2.5 M in hexane, 54.7 mL, 137 mmol, 1.1eq) was added to a solution of (S) -4-benzyloxazolidin-2-one (22 g, 124 mmol, 1eq) in dry THF (220 mL) at -60 ℃ under N₂ atomosphere. After stirring 30 min at -60 ℃, 2-fuoropropanoyl chloride (15.2 g, 137 mmol) was added dropwisely below -50 ℃ , after adding the solution was stirred for 1h at -50 ℃ to -60 ℃. The reaction was then quenched with a saturated solution of NH₄Cl, extracted with EtOAc, washed with NaHCO₃ (sat) , brine and dried over MgSO₄. Solvents were removed under reduced pressure. The product was purified over silica (hexane/EtOAc) and recovered as a brown oil (25.8 g, 82.7％) . ¹H-NMR(400 MHz, CDCl₃ ) ： δ 7.29-7.13 (m, 5 H) , 6.01-5.81 (qd, 1 H) , 4.71-4.58 (md, 1 H) , 4.29-4.04 (m, 2 H) , 3.32-3.16 (dd, 1 H) , 2.79-2.74 (m, 1 H) , 1.51 (m, 3 H) .

Example 7： preparation of (4R) -4-benzyl-3- (2-fluoropropanoyl) oxazolidin-2-one (9)

Use the procedure described in Example 6, (R) -4-benzyloxazolidin-2-one as the start material to give the desired compound (4R) -4-benzyl-3- (2-fluoropropanoyl) oxazolidin-2-one (yield: 85％) . ¹H-NMR (400 MHz, CDCl₃ ) ： δ 7.27 -7.12 (m, 5 H) , 6.00-5.83 (qd, 1 H) , 4.72-4.55 (md, 1 H) , 4.27-4.03 (m, 2 H) , 3.32 -3.16 (dd, 1 H) , 2.79 -2.72 (m, 1 H) , 1.53 (m, 3 H) .

[0221]

Example 8： preparation of (4R) -3- (2-fluoropropanoyl) -4-isopropyl-5, 5-diphenyloxazolidin-2-one (10)

[0222]

[0223]

n-Butyl lithium (2.5 M in hexane, 48 mL) was added to a solution of (R) -4-isopropyl-5,5-diphenyloxazolidin-2-one (28.1 g) in dry THF (150 mL) at -65 ℃ under N₂ atomosphere. After stirring 30 min at -60 ℃, 2-fuoropropanoyl chloride (16.4 g, 1.5 eq) was added dropwisely below -60 ℃. After adding the solution was stirred for 2 h at -60 ℃. The reaction was then quenched with a saturated solution of NH₄Cl, extracted with EtOAc, washed with NaHCO₃ (sat) , brine and dried over MgSO₄. Solvents were removed under reduced pressure. The crude product was recrystalized in (DCM/PE) to give (4R) -3- (2-fluoropropanoyl) -4-isopropyl-5, 5-diphenyloxazolidin-2-one (30 g, 85％) . ¹H-NMR (CDCl₃, 400 MHz) : δ 7.50 -7.26 (m, 10 H) , 5.89 (ddq, J ＝ 64.4, 49.3, 6.6 Hz, 1 H) , 5.37 (dd, J ＝ 70.8, 3.4 Hz, 1 H) , 2.00 (dd, J ＝ 7.3, 3.3 Hz, 1 H) , 1.70 (dd, J ＝ 23.4, 6.7 Hz, 1.5 H) , 1.12 (dd, J ＝ 23.8, 6.6 Hz, 1.5 H) , 0.83 (ddd, J ＝ 28.0, 16.7, 6.9 Hz, 6 H) .

[0224]

Example 9： preparation of (4S) -3- (2-fluoropropanoyl) -4-isopropyl-5, 5-diphenyloxazolidin-2-one (11)

[0225]

[0226]

Use the procedure described in Example 8 and (S) -4-isopropyl-5, 5-diphenyloxazolidin-2-one as the start material to give the desired compound (4S) -3- (2-fluoropropanoyl) -4-isopropyl- 5,5-diphenyl oxazolidin-2-one (yield: 82％) . ¹H-NMR (CDCl₃, 400 MHz) : δ 7.51 -7.27 (m, 10 H) , 5.90 (ddq, J ＝ 64.4, 49.3, 6.6 Hz, 1 H) , 5.38 (dd, J ＝ 70.8, 3.4 Hz, 1H) , 2.01 (dd, J ＝ 7.3, 3.3 Hz, 1 H) , 1.71 (dd, J ＝ 23.4, 6.7 Hz, 1.5 H) , 1.13 (dd, J ＝ 23.8, 6.6 Hz, 1.5 H) , 0.84 (ddd, J ＝ 28.0, 16.7, 6.9 Hz, 6 H) .

[0227]

Example 10： preparation of (R) -3- ( (2R, 3R) -2-fluoro-3-hydroxy-2-methylpent-4-enoyl) -4-isopropyloxazolidin-2-one (12)

[0228]

[0229]

Method A: TiCl₄ (1 M in DCM, 50 mL, 50 mmol, 1.1 eq) was added to a solution of (4R) -3- (2-fluoropropanoy l ) -4-isopropyloxazolidin-2-one (4) (10 g, 49.2 mmol, 1 eq) in dry DCM (170 mL) at -78 ℃ under N₂ atomosphere. After 10 min, diisopropylethyl amine (10.3 mL, 1.26 eq) was added and the solution was stirred for 2 hs at-78 ℃, then the second batch of TiCl₄ (1 M in DCM, 50 mL, 50 mmol, 1.1 eq) was added. After 10 min, acrylaldehyde (7 mL, 2 eq) was added and the solution was stirred for 1 h at -78 ℃. Then the reaction was quenched with a saturated solution of NH₄Cl (50 mL) . The products were extracted into DCM (20 mL *2) , washed with brine and dried over MgSO₄. Solvents were removed under reduced pressure and the product was recrystalized in toluene to give the desired compound as a white solid (10.2 g, yield: 80％, purity: 97.2％) . ¹H-NMR (400 MHz, CDCl₃) ： δ 5.89 (dddd, J ＝ 17.1, 10.5, 6.5, 0.8 Hz, 1 H) , 5.42 (d, J ＝17.2 Hz, 1 H) , 5.30 (d, J ＝ 10.1 Hz, 1 H) , 4.68 (dd, J ＝ 14.8, 6.5 Hz, 1 H) , 4.44 (d, J ＝ 4.0 Hz, 1 H) , 4.32 (t, J ＝ 8.5 Hz, 1 H) , 4.24 (dd, J ＝ 9.1, 3.4 Hz, 1 H) , 3.61 (d, J ＝ 6.5 Hz, 1 H) , 2.37 (dd, J ＝ 7.0, 4.1 Hz, 1 H) , 1.73 (s, 1.5 H) , 1.67 (s, 1.5 H) , 0.92 (ddd, J ＝ 7.8, 5.6, 2.4 Hz, 6 H) ； ¹⁹F-NMR (400 MHz, CDCl₃) : -158.3 ppm.

[0230]

Method B: TiCl₄ (1 M in DCM, 50 mL, 50mmol, 1.1 eq) was added to a solution of (4R) -3- (2-fluoropropanoy l ) -4-isopropyloxazolidin-2-one (10 g, 49.2 mmol, 1 eq) in dry DCM (170 mL) at -78 ℃ under N₂ atomosphere. After 10 min, (-) -spartein (14.5 g, 1.26 eq) was added and the solution was stirred for 2 hs at-78 ℃, then the second batch of TiCl₄ (1 M in DCM, 50 mL, 50 mmol, 1.1eq) was added. After 10 min, acrylaldehyde (7 mL, 2 eq) was added and the solution was stirred for 1 h at -78 ℃. Then the reaction was quenched with NH₄Cl (sat 50 mL) . The products were extracted into DCM (20 mL *2) , washed with brine and dried over MgSO₄. Solvents were removed under reduced pressure and the product was recrystalized in toluene to give the desired compound as a white solid (9.4 g, yield: 75％, purity: 96.5％) .

[0231]

Example 11： preparation of (S) -3- ( (2R, 3R) -2-fluoro-3-hydroxy-2-methylpent-4-enoyl) -4-isopropyloxazolidin-2-one (13)

[0232]

[0233]

TiCl₄ (1 M in DCM, 50 mL, 50 mmol, 1.1 eq) was added to a solution of (4S) -3- (2-fluoropropanoy l ) -4-isopropyloxazolidin-2-one (4) (10 g, 49.2 mmol, 1 eq) in dry DCM (170 mL) at -78 ℃ under N₂ atomosphere. After 10 min, diisopropylethyl amine (15.9 g, 2.5 eq) was added and the solution was stirred for 2 hs at-78 ℃. Then acrylaldehyde (7 mL, 2eq) was added and the solution was stirred for 1 h at -78 ℃. Then the reaction was quenched with a saturated solution of NH₄Cl (50 mL) . The products were extracted into DCM (20 mL *2) , washed with brine and dried over MgSO₄. Solvents were removed under reduced pressure and the product was recrystalized in toluene to give the desired compound as a white solid (10.4 g, yield: 83％, purity: 92.8％) . ¹H-NMR (400 MHz, CDCl₃) ： δ 5.92 (d， J ＝ 1.1 Hz， 1 H) ， 5.44 (d, J ＝ 17.2 Hz, 1 H) , 5.34 -5.28 (m, 1 H) , 4.73 (dd, J ＝ 13.9, 6.2 Hz, 1 H) , 4.43 (m, 1 H) , 4.37 -4.30 (m, 1H) , 4.27 -4.21 (m, 1 H) , 2.43 -2.31 (m, 1H) , 1.77 (s, 1.5 H) , 1.71 (s, 1.5 H) , 0.91 (dd, J ＝ 12.1, 7.0 Hz, 6 H) ； ¹⁹F-NMR (400 MHz, CDCl₃) ： δ -159.1ppm.

[0234]

Example 12： preparation of (S) -4-benzyl-3- ( (2R, 3R) -2-fluoro-3-hydroxy-2-methylpent-4-enoyl) oxazolidin-2-one

[0235]

[0236]

TiCl₄ (1 M in DCM, 50 mL, 50mmol, 1.1 eq) was added to a solution of (4S) -4-benzyl-3-(2-fluoro propanoyl) oxazolidin-2-one (8) (12.3 g, 49.2 mmol, 1 eq) in dry DCM (170 mL) at -78 ℃ under N₂ atomosphere. After 10 min, TMEDA (15.9 g, 2.5 eq) was added and the solution was stirred for 2 hs at -78 ℃. Then acrylaldehyde (7 mL, 2 eq) was added and the solution was stirred for 1 h at -78 ℃. Then the reaction was quenched with a saturated solution of NH₄Cl (50 mL) . The products were extracted into DCM (20 mL*2) , washed with brine and dried over MgSO₄. Solvents were removed under reduced pressure and the product was recrystalized in toluene to give the desired compound as a white solid (13 g, yield: 86％, purity: 91.5％) . ¹H-NMR (400 MHz, CDCl₃) ： δ 7.38 -7.27 (m, 3 H) , 7.22 (d, J ＝ 6.8 Hz, 2 H) , 5.96 (dddd, J ＝ 17.0, 10.5, 6.2, 1.2 Hz, 1 H) , 5.47 (d, J ＝ 17.2 Hz, 1 H) , 5.35 (d, J ＝ 10.5 Hz, 1 H) , 4.75 (dd, J ＝ 13.9, 6.2 Hz, 1 H) , 4.66 (td, J ＝ 7.1, 3.6 Hz, 1 H) , 4.23 (dd, J ＝ 16.3, 5.0 Hz, 2 H) , 3.33 (dd, J ＝ 13.3, 3.3 Hz, 1 H) , 2.76 (dd, J ＝13.3, 10.0 Hz, 1 H) , 1.81 (s, 1.5 H) , 1.76 (s, 1.5 H) ； ¹⁹F-NMR (400 MHz, CDCl₃) ： δ -158.47 ppm.

[0237]

Example 13： preparation of (S) -3- ( (2R, 3R) -2-fluoro-3-hydroxy-2-methylpent-4-enoyl) -4-phenyloxazolidin-2-one

[0238]

[0239]

TiCl₄ (1 M in DCM, 50 mL, 50 mmol, 1.1 eq) was added to a solution of (4S) -3- (2-fluoropropanoyl) -4-phenyloxazolidin-2-one (7) (11.6 g, 49.2 mmol, 1 eq) in dry DCM (170 mL) at -78 ℃ under N₂ atomosphere. After 10 min, Et₃N (12.5 g, 2.5 eq) was added and the solution was stirred for 2 hs at-78 ℃. Then acrylaldehyde (7 mL, 2 eq) was added and the solution was stirred for 1 h at -78 ℃. Then the reaction was quenched with a saturated solution of NH₄Cl (50 mL) . The products were extracted into DCM (20 mL *2) , washed with brine and dried over MgSO₄. Solvents were removed under reduced pressure and the product was recrystalized in toluene to give the desired compound as a white solid (12 g, yield: 83％, purity: 90.5％) . ¹H-NMR (400 MHz, CDCl₃) : δ 7.43 -7.30 (m, 5 H) , 5.81 (dddd, J ＝ 17.0, 10.5, 6.3, 1.1 Hz, 1 H) , 5.46 (dd, J ＝ 8.4, 5.1 Hz, 1 H) , 5.37 (dt, J ＝ 17.2, 1.2 Hz, 1 H) , 5.23 (d, J ＝ 10.4 Hz, 1 H) , 4.74 (t, J ＝ 8.7 Hz, 1 H) , 4.64 (dd, J ＝ 13.5, 6.3 Hz, 1 H) , 4.31 (dd, J ＝ 8.9, 5.2 Hz, 1 H) , 1.60 (s, 1.5H) , 1.55 (s, 1.5 H) ； ¹⁹F-NMR (400 MHz, CDCl₃) ： δ -158.47 ppm.

[0240]

Example 14： preparation of (R) -3- ( (2R, 3R) -2-fluoro-3-hydroxy-2-methylpent-4-enoyl) -4-phenyloxazolidin-2-one

[0241]

[0242]

TiCl₄ (1 M in DCM, 50 mL, 50mmol, 1.1 eq) was added to a solution of (4R) -3- (2-fluoro propan oyl) -4-phenyloxazolidin-2-one (6) (11.6 g, 49.2 mmol, 1 eq) in dry DCM (170 mL) at -78 ℃ under N₂ atomosphere. After 10 min, DIPEA (15.9 g, 2.5 eq) was added and the solution was stirred for 2 hs at-78 ℃. Then acrylaldehyde (7 mL, 2 eq) was added and the solution was stirred for 1 h at -78℃. Then the reaction was quenched with a saturated solution of NH₄Cl (50 mL) . The products were extracted into DCM (20 mL *2) , washed with brine and dried over MgSO₄. Solvents were removed under reduced pressure and the product was recrystalized in toluene to give the desired compound as a white solid (11.1 g, yield: 77％, purity: 91.5％) . ¹H-NMR (400 MHz, CDCl₃) : δ 7.44 -7.29 (m, 5 H) , 5.74 -5.63 (m, 1 H) , 5.48 (dd, J ＝ 8.4, 5.3 Hz, 1 H) , 5.35 -5.26 (m, 1 H) , 5.15 (d, J ＝ 10.5 Hz, 1 H) , 4.73 (t, 1 H) , 4.52 (dd, J ＝ 14.8, 6.2 Hz, 1 H) , 4.28 (dd, J ＝ 8.9, 5.3 Hz, 1 H) , 1.68 (s, 1.5 H) , 1.63 (s, 1.5 H) ； ¹⁹F-NMR (400 MHz, CDCl₃) ： δ -161.93 ppm.

[0243]

Example 15： preparation of (S) -3- ( (2R, 3R) -2-fluoro-3-hydroxy-2-methylpent-4-enoyl) -4-isopropyl-5, 5-diphenyloxazolidin-2-one

[0244]

[0245]

Method 1: LiHMDS (1 M in THF, 50 mL, 50 mmol, 1.1 eq) was added to a solution of (4S) -3- (2-fluoro propanoyl) -4-isopropyl-5, 5-diphenyloxazolidin-2-one (11) (17.4 g, 49.2 mmol, 1 eq) in dry THF (100 mL) at -20 ℃ under N₂ atomosphere. After 1.5 hs, acrylaldehyde (7 mL, 2 eq) was added and the solution was stirred for 1 h at -20 ℃. Then the reaction was quenched with a saturated solution of NH₄Cl (50 mL) . The products were extracted into EA (50 mL *2) , washed with brine and dried over MgSO₄. Solvents were removed under reduced pressure and the crude product was used directly in the next step. m/z (ES+) : 412 [M+H] +.

[0246]

Method 2: (n-Bu) ₂BOTf (1 M in DCM, 50 mL, 50 mmol, 1.1 eq) was added to a solution of (4S) -3- (2-fluoro propanoyl) -4-isopropyl-5, 5-diphenyloxazolidin-2-one (11) (17.4 g, 49.2 mmol, 1 eq) in dry DCM (100 mL) at 0 ℃ under N₂ atomosphere. After 15 min, 2, 6-lutidine (10.5g, 2eq) was added and the solution was stirred for 2 hs at 0 ℃. Then acrylaldehyde (7 mL, 2 eq) was added and the solution was stirred for 1 h at 0 ℃. Then the reaction was quenched with a saturated solution of NH₄Cl (100 mL) . The products were extracted into DCM (40 mL *2) , washed with brine and dried over MgSO₄. Solvents were removed under reduced pressure and the crude product was used directly in the next step (17.82 g, yield: 88％ (Internal standard yield) .

[0247]

Method 3: (n-Bu) ₂BOTf (1 M in DCM, 50 mL, 50 mmol, 1.1 eq) was added to a solution of (4S) -3- (2-fluoro propanoyl) -4-isopropyl-5, 5-diphenyloxazolidin-2-one (11) (17.4 g, 49.2 mmol, 1 eq) in dry DCM (100 mL) at 0 ℃ under N₂ atomosphere. After 15 min, DIPEA (13 g, 2 eq) was added and the solution was stirred for 2 hs at 0 ℃. Then acrylaldehyde (7 mL, 2 eq) was added and the solution was stirred for 1 h at 0 ℃. Then the reaction was quenched with a saturated solution of NH₄Cl (100 mL) . The products were extracted into EA (50 mL *2) , washed with brine and dried over MgSO₄. Solvents were removed under reduced pressure and the crude product was used directly in the next step (16.2 g, yield: 80％ (Internal standard yield ) .

[0248]

Method 4: (C₆H₁₂) ₂BOTf (1 M in DCM, 50 mL, 50 mmol, 1.1 eq) was added to a solution of (4S) -3- (2-fluoro propanoyl) -4-isopropyl-5, 5-diphenyloxazolidin-2-one (11) (17.4 g, 49.2 mmol, 1 eq) in dry DCM (100 mL) at 0 ℃ under N₂ atomosphere. After 15 min, 2, 6-lutidine (10.5 g, 2 eq) was added and the solution was stirred for 2 hs at 0 ℃. Then acrylaldehyde (7 mL, 2 eq) was added and the solution was stirred for 1 h at 0 ℃. Then the reaction was quenched with a saturated solution of NH₄Cl (100 mL) . The products were extracted into DCM (50 mL *2) , washed with brine and dried over MgSO₄. Solvents were removed under reduced pressure and the crude product was used directly in the next step (14.6 g, yield: 80％ (Internal standard yield ) .

[0249]

Example 16： preparation of (3R, 4R, 5R) -3-fluoro-4-hydroxy-5- (hydroxymethyl) -3-methyl dihydro furan-2 (3H) -one

[0250]

Method 1:

[0251]

[0252]

N-Bromosuccinimide (19.6 g, 1.1 eq) was added portionwisely to a solution of (R) -3- ( (2R, 3R) -2-fluoro-3-hydroxy-2-methylpent-4-enoyl) -4-isopropyloxazolidin-2-one (12) (25.9 g, 100 mmol, 1 eq) in DME/H₂O (4: 1, 130ml) at -5 ℃, and stirred for 2 hs . After the reaction was complete, NaHCO₃ (sat, 20 mL) was added and stirred for 0.5 h at rt. The mixture were extracted by DCM (50 mL *2) , washed with brine and dried over MgSO₄. Solvents were removed, the residue dissolved by MTBE (1V) , the solid was filtered off to recover the auxiliary, the filtrate was concentrated to dryness to obtained the (3R, 4R, 5R) -5- (bromomethyl) -3-fluoro-4-hydroxy-3-methyldihydrofuran-2 (3H) -one (18a) . ¹H-NMR (400 MHz, CDCl₃) : δ 4.62 -4.53 (m, 1 H) , 4.37 (dd, J ＝ 3.0, 1.9 Hz, 1 H) , 3.73 (dd, J ＝ 10.1, 8.7 Hz, 1 H) , 3.60 (ddd, J ＝ 10.1, 5.8, 1.9 Hz, 1 H) , 2.59 (dd, J ＝ 2.5, 1.7 Hz, 1 H) , 1.67 (d, J ＝ 22.7 Hz, 3 H) ； ¹⁹F-NMR (400 MHz, CDCl₃) ： δ -172.248 ppm.

[0253]

Alternative Method 1a: Br₂ (17.6 g, 1.1 eq) was added portionwisely to a solution of (R) -3- ( (2R, 3R) -2-fluoro-3-hydroxy-2-methylpent-4-enoyl) -4-isopropyloxazolidin-2-one (12) (25.9 g, 100 mmol, 1 eq) in MeCN/H₂O (4: 1, 130 mL) between -5 ℃ to -10 ℃ and stirred for 2 hs . After the reaction was complete, Na₂S₂O₃ (10％, 20 ml) was added and stirred for 0.5 h at rt then separated . The water phase was re-extracted by DCM (50 mL *2) , the combine organic phase was concentrated, dissolved by MTBE (1V) , the solid was filtered off to recover the auxiliary, the filtrate was concentrated to dryness to used in the next step.

[0254]

Alternative Method 1b: N-chlorosuccinimide (13.3 g, 1.1 eq) was added portionwisely to a solution of (R) -3- ( (2R, 3R) -2-fluoro-3-hydroxy-2-methylpent-4-enoyl) -4-isopropyloxazolidin-2-one (12) (25.9 g, 100 mmol, 1 eq) in 100ml CH3CN at -5 ℃, and stirred for 2 hs . After the reaction was complete, NaHCO₃ (sat, 20 mL) was added and stirred for 0.5 h at rt. The mixture were extracted by DCM (50 mL *2) , washed with brine and dried over MgSO₄. Solvents were removed, the residue dissolved by MTBE (1V) , the solid was filtered off to recover the auxiliary, the filtrate was concentrated to dryness to obtained the (3R, 4R, 5R) -5- (chloromethyl) -3-fluoro-4-hydroxy-3-methyldihydrofuran-2 (3H) -one (18b) , m/z (ES+) : 183 [M+H] +.

[0255]

The related lactone 18a or 18b (0.14eq) was dissolved in EtOH (104 mL) , then KOH (30％in H₂O, 50 mL) was added into, the result mixture was reflux for 4 hs. Then HCl (16.7 mL, 12 M) was added into the mixture and reflux for another 2 hs. The solvent was removed and the residue was recrystalized in toluene to give the desired compound as a white solid (yield: 80～85％) . m/z (ES+) : 165 [M+H] +. ¹H-NMR (400 MHz, MeOD) : δ 4.34 (ddd， J ＝ 8.0， 4.2， 2.3 Hz， 1 H) , 4.02 (ddd, J ＝ 17.6, 15.2, 5.1 Hz, 2 H) , 3.74 (dd, J ＝ 13.0, 4.2 Hz, 1 H) , 1.60 (s, 1.5 H) , 1.54 (s, 1.5 H) ； ¹⁹F-NMR (400 MHz, MeOD) : -172.47 ppm.

[0256]

Method 2:

[0257]

[0258]

Osmium tetroxide (OsO4) (0.1 equiv) was added in one portion to a stirring solution of the (R) -3- ( (2R, 3R) -2-fluoro-3-hydroxy-2-methylpent-4-enoyl) -4-isopropyloxazolidin-2-one (12) (25.9 g, 100 mmol, 1 eq) in acetone/water (8: 1 ratio) under nitrogen. After 5 min, NMO (N-methylmorpholine N-oxide, 60％by weight in water, 1.1 equiv) was added in one portion and stirred for 24 h. The resulting reaction mixture was concentrated under reduced pressure and immediately purified via column chromatography to obtain the desired lactone (3R, 4R, 5S) -3-fluoro-4-hydroxy-5- (hydroxymethyl) -3-methyldihydrofuran-2 (3H) -one (21) , yield: 87％, m/z (ES+) : 165 [M+H] +.

[0259]

15.1 g (92.3 mmol) (3R, 4R, 5S) -3-fluoro-4-hydroxy-5- (hydroxymethyl) -3-methyl dihydrofuran-2 (3H) -one (21) was dissolved in 25 mL pyridine and 11.1 g (96.9 mmol) methanesulfonyl chloride was slowly added dropwise at -25 degC. It was stirred for a day at -25 deg and a day at -10 deg. After adding 20 mL of ethyl acetate and 20 mL water, the solvent was removed on a rotary evaporator. After neutralization with dilute sodium hydrogen carbonate solution, the solvent was removed in vacuo again, the residue was digested with ethyl acetate, the eluate was dried with magnesium sulfate and concentrated in vacuo to dryness. Recrystallization from ethyl acetate/diethyl ether gave a colorless crystalline product ( (2S, 3R, 4R) -4-fluoro-3-hydroxy-4-methyl-5-oxotetrahydrofuran-2-yl) methyl methanesulfonate (18c) . Yield: 31 ％.

[0260]

33.8g of ( (2S, 3R, 4R) -4-fluoro-3-hydroxy-4-methyl-5-oxotetrahydrofuran-2-yl) methyl methanesulfonate was disslolved in EtOH (104 mL) , then KOH (16.8 g , 3 eq) in H₂O (52 mL) was added into, the result mixture was reflux for 4 hs. Then HCl (16.7 mL, 12 M) was added into, the mixture was reflux for another 2 hs. The solvent was removed and the residue was recrystalized in toluene to give the desired compound as a white solid (10.5 g, yield: 45％) .

[0261]

Alternative reagents and reactions to those disclosed above can also be employed. For example, 4-methylbenzene-1-sulfonyl chloride can be used instead of methanesulfonyl chloride. Moreover, primary alcohol can be converted to chloro or bromo by using Ph₃P/CCl4, PPh₃P/CBr₄, PPh₃/NCS, PPh₃/NBS, or PPh₃/C₂Cl₆ as a halogenation reagent. The desired product can be obtained in good yields using these reagents and reactions.

[0262]

Method 3: Using a method analogous to that described as hereinabove and (S) -3- ( (2R, 3R) -2-fluoro-3-hydroxy-2-methyl pent-4-enoyl) -4-isopropyloxazolidin-2-one (13) as starting material provides the desired compound 19 (yield: 63.2％)

[0263]

Method 4： Using a method analogous to that described as hereinabove and (S) -4-benzyl-3- ( (2R, 3R) -2-fluoro-3-hydroxy-2-methylpent-4-enoyl) oxazolidin-2-one (14) as starting material provides the desired compound 19 (yield: 71.8％)

[0264]

Method 5： Using a method analogous to that described as hereinabove and (S) -3- ( (2R, 3R) -2-fluoro-3-hydroxy-2-methylpent-4-enoyl) -4-phenyloxazolidin-2-one (15) as the start material gives the desired compound 19 (yield: 65.7％)

[0265]

Method 6： Using a method analogous to that described as hereinabove and (R) -3- ( (2R, 3R) -2-fluoro-3-hydroxy-2-methylpent-4-enoyl) -4-phenyloxazolidin-2-oneas (16) starting material provides the desired compound 19 (yield: 59.5％)

[0266]

Method 7： Using a method analogous to that described as hereinabove and (S) -3- ( (2R, 3R) -2-fluoro-3-hydroxy-2-methylpent-4-enoyl) -4-isopropyl-5, 5-diphenyloxazolidin-2-one (17) as starting material gives the desired compound 19 (yield: 66.7％)

[0267]

Example 17: preparation of ( (3R, 4R) -3- (benzoyloxy) -4-fluoro-4-methyl-5-oxotetra hydro fur an-2-yl) methyl benzoate

[0268]

[0269]

(3R, 4R) -3-fluoro-4-hydroxy-5- (hydroxymethyl) -3-methyldihydrofuran-2 (3H) -one (19) (25.4 g, 0.154 mol) obtained from example 3 was dissolved in 200 ml of THF. 4- (Dimethylamino) -pyridine (8.2 g, 0.066 mol) and triethylamine (35 g, 0.35 mol) were added and the reaction mixture was cooled to 0 ℃. Benzoyl chloride (46.0 g, 0.33 mol) was added, and the mixture was warmed to 35-40 ℃ in the course of 2 hs. Upon completion of the reaction, water (100 mL) was charged and the mixture was stirred for 30 min. Phases were separated and to the aqueous phase methyl-tert-butyl ether (100 mL) was added and the mixture was stirred for 30 min. Phases were separated and the organic phase was washed with saturated NaCl solution (100 mL) . The combined organic phases were dried over Na₂SO₄ (20 g) filtered and the filtrate was evaporated to dryness. The residue was taken up in iso-propanol (250 mL) and the mixture was warmed to 50 ℃ and stirred for 60 min, then cooled down to 0 ℃ and further stirred for 60 min. The solid was filtered and the wet cake was washed with i-propanol (50 mL) and then dried under vacuum. The title compound ( (3R, 4R) -3- (benzoyloxy) -4-fluoro-4-methyl-5-oxotetrahydrofuran-2-yl) methyl benzoate (47.5 g, 82.6 ％yield) was obtained. ‘H-NMR (CDCl₃, 400 MHz) : 8.10 (d, 7＝7.6 Hz, 2H) , 8.00 (d, 7＝7.6 Hz, 2H) , 7.66 (t, 7＝7.6 Hz, IH) , 7.59 (t, 7＝7.6 Hz, IH) , 7.50 (m, 2H) , 7.43 (m, 2H) , 5.53 (dd, 7＝17.6, 5.6 Hz, IH) , 5.02 (m, IH) , 4.77 (dd, 7＝12.8, 3.6 Hz, IH) , 4.62 (dd, 7＝12.8, 5.2 Hz, IH) , 1.77 (d, 7＝23.2 Hz, 3H) .

///////////////////

DAROLUTAMIDE, WO 2018036558, 苏州科睿思制药有限公司 , New patent

PATENTS, Uncategorized Comments Off

Mar 142018

DAROLUTAMIDE, WO 2018036558, 苏州科睿思制药有限公司 , New patent

WO-2018036558-A1 / 2018-03-01

CRYSTAL FORM OF ANDROGEN RECEPTOR ANTAGONIST MEDICATION, PREPARATION METHOD THEREFOR, AND USE

陈敏华 [CN][+]

张炎峰 [CN][+]

李骄洋 [CN][+]

鄢楷强 [CN][+]

刘启月 [CN][+]

张晓宇 [CN]

一种式(I)所示ODM-201的晶型B，其特征在于，其X射线粉末衍射在衍射角2θ为16.2°±0.2°、9.0°±0.2°、22.5°±0.2°处有特征峰。

Image loading...

Novel crystalline forms of an androgen receptor antagonist medication, particularly ODM-201 (also known as darolutamide; designated as Forms B and C), processes for their preparation and compositions comprising them are claimed. Represents a first filing from Crystal Pharmaceutical Co Ltd and the inventors on this API.

Orion and licensee Bayer are codeveloping darolutamide, an androgen receptor antagonist, for treating castration-resistant prostate cancer and metastatic hormone-sensitive prostate cancer.

专利CN102596910B公开了ODM-201的制备方法，但并未公开任何的晶型信息。专利WO2016120530A1公开了式(I)(CAS号：1297538-32-9)所示的晶型I，式(Ia)(CAS号：1976022-48-6)所示的晶型I’和式(Ib)(CAS号：1976022-49-7)所示的晶型I”。文献Expert Rev.Anticancer Ther.15(9),(2015)已报道：ODM-201是由1:1比例的(Ia)和(Ib)两种非对应异构体组成，即为式(I)所示结构。因此，现有关于ODM-201的晶型只有晶型I报道。

Image loading...

Prostate cancer has become an important disease threatening the health of men. Its incidence is higher in western countries and shows a year-by-year upward trend. In the past, Asian countries with a lower incidence of the disease have also seen an increase in the number of patients in recent years. Clinical treatment of prostate cancer commonly used methods are surgical resection, radiation therapy and blocking androgen endocrine therapy. Androgen is closely related to the growth of prostate and the occurrence of prostate cancer. Therefore, endocrine therapy has become an effective way to treat prostate cancer. The method includes orchidectomy, estrogen therapy, gonadotropin-releasing hormone analog therapy, gonadotropin-releasing hormone antagonist therapy, androgen antagonistic therapy, etc., wherein androgen antagonist therapy can be both early treatment of prostate cancer can also be combined Surgery for adjuvant therapy is currently one of the main clinical treatment of prostate cancer. Androgen receptor as a biological target of androgen play an important role in the field of biomedical research.

Clinical trials have shown that exogenous androgen administration to patients with prostate cancer can lead to an exacerbation of the patient’s condition; conversely, if the testicles are removed and the level of androgens in the patient is reduced, the condition is relieved, indicating that androgens contribute to the development of prostate cancer Significant influence. According to receptor theory, androgen must bind with androgen receptor (AR) to cause subsequent physiological and pathological effects, which is the basis for the application of androgen receptor (AR) antagonist in the treatment of prostate cancer. In vitro experiments have shown that AR antagonists can inhibit prostate cell proliferation and promote apoptosis. Depending on the chemical structure of AR antagonists, they can be divided into steroidal AR antagonists and non-steroidal AR antagonists. Non-steroidal anti-androgen activity is better, there is no steroid-like hormone-like side effects, it is more suitable for the treatment of prostate cancer.

ODM-201 (BAY-1841788) is a non-steroidal oral androgen receptor (AR) antagonist used clinically to treat prostate cancer. The binding affinity of ODM-201 to AR was high, with Ki = 11nM and IC50 = 26nM. Ki was the dissociation constant between ODM-201 and AR complex. The smaller the value, the stronger the affinity. half maximal inhibitory concentration “refers to the half-inhibitory concentration measured, indicating that a certain drug or substance (inhibitor) inhibits half the amount of certain biological processes. The lower the value, the stronger the drug’s inhibitory ability. In addition, ODM-201 does not cross the blood-brain barrier and can reduce neurological related side effects such as epilepsy. Bayer Corporation has demonstrated in clinical trials the effectiveness and safety of ODM-201, demonstrating its potential for treating prostate cancer.

The chemical name of ODM-201 is: N – ((S) -l- (3- (3- chloro-4-cyanophenyl) -lH-pyrazol-l-yl) -propan- The chemical name contains the tautomer N – ((S) -1- (3- (3- 4-cyanophenyl) -1H-pyrazol- 1 -yl) -propan-2-yl) -5- (1 -hydroxyethyl) 1297538-32-9, the structural formula is shown in formula (I) :

Image loading...

The different crystalline forms of solid chemical drugs can lead to differences in their solubility, stability, fluidity and compressibility, thereby affecting the safety and efficacy of pharmaceutical products containing the compounds (see K. Knapman, Modern Drug Discovery, 3, 53 -54,57,2000.), Resulting in differences in clinical efficacy. It has been found that new crystalline forms (including anhydrates, hydrates, solvates, etc.) of the active ingredients of the medicinal product may give rise to more processing advantages or provide substances with better physical and chemical properties such as better bioavailability, storage stability, ease Processed, purified or used as an intermediate to promote conversion to other crystalline forms. The new crystalline form of the pharmaceutical compound can help improve the performance of the drug and broaden the choice of starting material for the formulation.

Patent CN102596910B discloses the preparation of ODM-201, but does not disclose any crystal form information. Patent WO2016120530A1 discloses a crystalline form I represented by the formula (I) (CAS number: 1297538-32-9), a crystalline form I ‘represented by the formula (Ia) (CAS number: 1976022-48-6) and a compound represented by the formula (CAS No. 1976022-49-7). Document Expert Rev. Anticancer Ther. 15 (9), (2015) It has been reported that ODM-201 is composed of a 1: 1 ratio of (Ia) And (Ib), which is the structure shown in Formula (I), so the only existing crystal form I for ODM-201 is reported.

Image loading...

However, the lower solubility of Form I and the high hygroscopicity, and the preparation of Form I requires the use of highly toxic acetonitrile solvents, which are carcinogenic in animals and are the second class of solvents that should be controlled during the process development stage. Form I preparation method is more complex, long preparation cycle, the process needs heating, increasing the cost of industrial preparation, is not conducive to industrial production. In order to overcome the above drawbacks, there is still a need in the art for a systematic and comprehensive development of other polymorphs of ODM-201 of formula (I), simplifying the preparation thereof, enabling its pharmacological development and releasing its potential, Preparation of a better formulation of the drug ingredients.

The inventors found through experiments that Form B and Form C of the present invention, and found that Form B and Form C of the present invention have more excellent properties than the prior art. Dissolution is a prerequisite for drug absorption, and increased solubility will help to increase the bioavailability of the drug and thereby improve the drug’s druggability. Compared with the prior art, the crystalline forms B and C of the invention have higher solubility and provide favorable conditions for drug development. Compared with the prior art, the crystalline forms B and C of the invention also have lower hygroscopicity. Hydroscopic drug crystal form due to adsorption of more water lead to weight changes, so that the raw material crystal component content is not easy to determine. In addition, the crystalline form of the drug substance absorbs water and lumps due to high hygroscopicity, which affects the particle size distribution of the sample in the formulation process and the homogeneity of the drug substance in the preparation, thereby affecting the dissolution and bioavailability of the sample. The crystal form B and the crystal form C have the same moisture content under different humidity conditions, and overcome the disadvantages caused by high hygroscopicity, which is more conducive to the long-term storage of the medicine, reduces the material storage and the quality control cost.

In addition, the present invention provides Form B and Form C of ODM-201 represented by formula (I), which have good stability, excellent flowability, suitable particle size and uniform distribution. The solvent used in the preparation method of crystal form B and crystal form C of the invention has lower toxicity, is conducive to the green industrial production, avoids the pharmaceutical risk brought by the residue of the toxic solvent, and is more conducive to the preparation of the pharmaceutical preparation. The novel crystal type provided by the invention has the advantages of simple operation, no need of heating, short preparation period and cost control in industrialized production. Form B and Form C of the present invention provide new and better choices for the preparation of pharmaceutical formulations containing ODM-201, which are of great significance for drug development.

The problem to be solved by the invention

The main object of the present invention is to provide a crystal form of ODM-201 and a preparation method and use thereof.

//////////DAROLUTAMIDE, WO 2018036558, 苏州科睿思制药有限公司 , New patent, CRYSTAL

Drug Patent expiry in 2017

PATENTS Comments Off

Jan 102017

Image result for PATENT EXPIRATIONS

“ALL FOR DRUGS” CATERS TO EDUCATION GLOBALLY, No commercial exploits are done or advertisements added by me. This article is a compilation for educational purposes only.

P.S. : The views expressed are my personal and in no-way suggest the views of the professional body or the company that I represent

///////////Drug Patent, expiry, 2017

How to Extend the Life of a Patent

PATENTS Comments Off

Dec 182016

ALL CREDIT TO WIKIHOW

How to Extend the Life of a Patent

Three Methods:

Determining Eligibility

Extending Your Patent

Contacting Congress

A patent ensures that an inventor is able to profit from his or her invention by preventing others from making, using, selling, or importing it without consent. Once the patent expires, the invention is free for the public to use without paying you. If you meet certain requirements, you may wish to extend your patent.Take advantage of this opportunity to have extra time added to your patent term and keep your invention out of the public domain longer.

Method1

Determining Eligibility

Determine the status of your patent. The United States Patent and Trademark Office (USPTO) keeps a website database of patent information. Access the USPTO database to check on your patent status. If you can’t find all the information you are looking for in the text-based display, then look at the patent image in PDF format.
- You can also look up European patents here.
- Or check Google Patents.
- Patents cannot be renewed and you can’t get the rights to an expired patent. ^[1]
Know what kind of patent you have. In the US, 2 main types of patents are given: utility patents or design patents. Utility patents cover the function of an invention and design patents protect the way an invention looks. Utility patents generally last 20 years, while design patents last 14 years or 15 years for those filed on or after May 13, 2015. There are also 20 year long plant patents for inventors who asexually reproduce a newly discovered or invented variety of plant.^[2]
Find out if you qualify. Patent extensions are sometimes granted if there are government regulatory delays or if newer laws extend the length of a patent. Sometimes, with very strong justification, you can try to get Congress to pass a bill to extend your patent. If you fall into one of these categories, then you may be able to get your patent extended.
Be aware that extensions may not be an option. For most inventions, the given term for your patent will stand. Recognize that you may not be able to extend your patent for this particular invention. Focus, instead, on developing a new invention that you can then get a new patent for.

Method2

Extending Your Patent

Get a term adjustment. If you filed your patent after May 29, 2000 and your patent was delayed because the USPTO was taking longer than normal to process the paperwork, you may be eligible to file for an extension. The extension will cover the time lost from your patent term for the delay. The length of the extension you are approved for will depend on the delay time frame, but will not be longer than 5 years.
Increase your original patent term. If you were initially granted less time than later legislation allows, you may be eligible to request an extension on your patent for the newer patent term. Under the Uruguay Rounds Agreements Act, utility patents granted before June of 1995 may be given an extension to 20 years instead of the original 17 years. This does not apply to design patents.
Get an extension under the Hatch-Waxman Act. A patent term restoration under the Hatch-Waxman Act is sometimes given to those who qualify.This applies to those whose products or processes, such as medications, medical devices, food and color additives, require testing and approval by the Food and Drug Administration’s (FDA) before they can be marketed. The period of time that you were unable to sell your product because you were awaiting FDA approval may be restored as an extension to the original patent. ^[3]
File for an extension with the United States Patent and Trademark Office (USPTO). All application forms for patent extensions can be found on the USPTO website: here for applications filed before September 16, 2012 and here for those filed after this time frame. Know that there are filing fees associated with this application.The process for filing for the extension depends upon which reason for extension the patent falls under.
- Generally, the application for extension must be in writing, include the identifying information for the patent, information about why the applicant is entitled to an extension, relevant dates to determine the length of the extension, copies of the patent documents, etc.
- Be sure to check with the USPTO for the exact amount of the fee (around $1,000) and the proper procedure for requesting the extension for your case.
Wait to hear back from the USPTO. It can take up to several months for the USPTO to process your request. As with any government process, patience is best. If you are eligible and have a good reason for an extension, then there’s a chance you could be approved so waiting is worth it.
Request an administrative hearing. If your extension request is denied, you have the right to appeal your denied request. Appeal forms can be found on the USPTO website: here for applications filed before September 16, 2012 and here for those filed after this time frame. Reasons for denial include defects in the paperwork you submitted to the USPTO asking for the extension and your invention being ineligible for extension. File an appeal and address any of the issues that your extension was denied in your written appeal.
- The appeals process begins with your Notice of Appeal and fee payment. It will continue through various steps until it reaches the Patent Trial and Appeal Board. The board will make a decision on your case and complete the appeals process.
Meet with an intellectual property lawyer. It could be very beneficial to consult with an attorney to review your options, especially if your request is denied. Your lawyer may be able to offer suggestions and ways to supplement your application. Filing for a patent extension can be complex and your lawyer can ensure that it is done correctly.

Method3

Contacting Congress

Be realistic. This is the least common form of attempting to extend a patent. Congress may not grant your request unless you have very convincing evidence for doing so. You also may need strong support from the community or a special interest group with persuasive lobbyists on your side.
- Congress extended the copyright of works to 95 years over the original 75 in 1998. This was due mainly to influential corporations like the Walt Disney Company lobbying for the modification.^[4] Keep the kind of influence you may require in mind when you decide to send a bill requesting a patent extension through Congress on your behalf.
Find a representative. Do some research on representatives in your area or someone you think would want to sponsor you in extending your patent. You will need to convince him or her that there is a very important reason you must extend your patent. It is best if they have a record of supporting the type of invention you have or are connected in some way to that field.
- Only a member of Congress can propose private legislation to the legislative body.
Draft a bill. It’s a good idea to do as much of the legwork as possible before approaching your representative. Your bill should be written in legal language and go over the reasons your patent should be granted an extension. You can check existing bills on the Congress website to get an idea what a bill looks like. It might be helpful to consult with a patent attorney when you’re writing this as legalese can be difficult to master.^[5]
- Create a preamble. This is an introduction and general overview about your patent, the date it will expire and an explanation of why you need an extension on your patent.
- Write up a body clause. This is the meat of your biIl and contains clauses that show what action needs to be taken—in this case, you want your patent to be extended.
- Finish with an enactment clause. This tells when you want the bill to take effect. This will be the day your patent is due to expire.
- Know that bills which need to take effect in 90 days or less will need 2/3 majority vote, while those that take effect after that time period will only require a majority vote. Send your bill in as early as possible.^[6]
Submit your bill to your potential sponsor. Contact your representative by phone or email. Many have websites where you can fill out a form to submit your case. Be sure to ask what the process is like and when you can expect to hear back.
Get a lobbyist to represent you. If your patent is important to certain groups or not extending it could cause harm, then look for someone with contacts to represent you. Lobbyist groups can put pressure on Congress to extend your patent. In order to do this, you need to have a good cause with far-reaching effects if your patent is not extended.
Be patient. The legislative process can take time. It must go through multiple committees before the house will vote on it. After that, it must be signed in. The length of time this will take varies and is something you should discuss with your sponsor.

Tips

It is best to file for an extension as soon as possible, as the USPTO generally takes months to process most filings.

Warnings

The request for patent extension should be made 3 months prior to the date on which the patent is set to expire.

Sources and Citations

WO 2016181414, IVACAFTOR, NEW PATENT, COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH

PATENTS Comments Off

Nov 242016

Image result for COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH Image result for REDDY SRINIVASA DUMBALA

CSIR, Dr. D. Srinivasa Reddy

WO2016181414, PROCESS FOR THE SYNTHESIS OF IVACAFTOR AND RELATED COMPOUNDS

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2016181414&recNum=1&maxRec=&office=&prevFilter=&sortOption=&queryString=&tab=PCTDescription

REDDY, Dumbala Srinivasa; (IN).
NATARAJAN, Vasudevan; (IN).
JACHAK, Gorakhnath Rajaram; (IN)

COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH [IN/IN]; Anusandhan Bhawan, Rafi Marg New Delhi 110001 (IN)

The present patent discloses a novel one pot two-step process for the synthesis of ivacaftor and related compounds of [Formula (I)], wherein R¹, R², R³, R⁴, R⁵, R⁶, R⁷ and Ar₁are as described above; its tautomers or pharmaceutically acceptable salts thereof starting from indole acetic acid amides

See Eur J Org Chem, Nov 2015, for an article by the inventors, describing a process for preparing ivacaftor using 4-quinolone-3-carboxylic acid amides. The inventors appear to be based at National Chemical Laboratories of CSIR.

Ivacaftor, also known as N-(2,4-di-tert-butyl-5-hydroxyphenyl)-l,4-dihydro-4-oxoquinoline-3-carboxamide, having the following Formula (A):

Formula (A)

[003] Ivacaftor was approved by FDA and marketed by vertex pharma for the treatment of cystic fibrosis under the brand name KALYDECO® in the form of 150 mg oral tablets. Kalydeco® is indicated for the treatment of cystic fibrosis in patients age 6 years and older who have a G55ID mutation in the CFTR (cystic fibrosis transmembrane conductance regulator)gene.

[004] U.S. 20100267768 discloses a process for preparation of ivacaftor, which involves the coupling of 4-oxo-l,4-dihydro-3- quinoline carboxylic acid with hydroxyl protected phenol intermediate in the presence of propyl phosphonic anhydride (T₃P®) followed by deprotection of hydroxyl protection group and optional crystallization with isopropyl acetate. The publication also discloses the use of highly expensive coupling reagent, propyl phosphonic anhydride; which in turn results to an increase in the manufacturing cost. The process disclosed is schematically represented as follows:

[005] Article titled “Discovery of N-(2,4-Di-te -butyl-5-hydroxyphenyl)-4-oxo-l,4-dihydroquinoline-3-carboxamide (VX-770, Ivacaftor), a Potent and Orally Bioavailable CFTR Potentiator” byHadida,S et. al in . Med. Chem., 2014, 57 (23), pp 9776-9795 reportsN-(2,4-di-teri-butyl-5-hydroxyphenyl)-4-oxo- 1 ,4-dihydroquinoline-3-carboxamide (VX-770, 48, ivacaftor), an investigational drug candidate approved by the FDA for the treatment of CF patients 6 years of age and older carrying the G551D mutation.

[006] WO 2014125506 A2 discloses a process for the preparation of ivacaftor in high yield and purity by using novel protected quinolone carboxylic acid compounds as intermediates.

[007] Article titled “Expeditious synthesis of ivacaftor” by Jingshan Shen et. al in Heterocycles, 2014, 89 (4), pp 1035 – 1040 reports an expeditious synthesis for ivacaftor featuring modified Leimgruber-Batcho procedure. The overall yield is 39% over six steps from commercially available 2-nitrobenzoyl chloride.

[008] U.S.2011/064811 discloses a process for preparation of ivacaftor, which involves condensation of 4-oxo-l,4-dihydro-3- quinolone carboxylic acid with 5- amino-2,4-di-(tert-butyl)phenol in the presence of HBTU followed by the formation of ethanol crystalate, which is then treated with diethyl ether to yield ivacaftor as a solid.

[010] U.S. 7,495,103 discloses modulators of ATP-binding cassette transporters such as ivacaftor and a process for the preparation of modulators of ATP-binding cassette transporters such as quinolone compounds. The process includes condensation of 4-oxo-l,4-dihydro-3 -quinolone carboxylic acid with aniline in presence of 2-(lH-7-azabenzotriazol-l-yl)-l,l,3,3-tetramethyluronium hexafluoro phosphate methanaminium (HATU) as shown:

[011] U.S. 2011/230519 discloses a process for preparation of 4-oxo-l,4-dihydro-3-quinoline carboxylic acid by reaction of aniline with diethylethoxymethylenemalonate at 100-110°C followed by cyclization in phenyl ether at temperature 228-232°C and then hydrolysis, as shown below:

[012] US 7,402,674 B2 discloses 7-Phenylamino-4-quinolone-3-carboxylic acid derivatives, process for their preparation and their use as medicaments.

[013] US 4,981,854 discloses l-aryl-4-quinolone-3 carboxylic acids, processes for their preparation and anti-bacterial agents and feed additives containing these compounds.

Article titled “Ozonolysis Applications in Drug Synthesis” by Van Ornum,S.G. ; Champeau,R.M.; Pariza,R. in Chem. Rev., 2006, 106 (7), pp 2990-3001 reports that ozonolysis for the synthesis of numerous interesting bioactive natural products and pharmaceutical agents.

[014] Article titled “Safe Execution of a Large-Scale Ozonolysis: Preparation of the Bisulfite Adduct of 2-Hydroxyindan-2-carbox-aldehyde and Its Utility in a Reductive Animation” by RaganJ.A. et. al. in Org. Proc. Res. Dev., 2003, 7 (2), pp 155-160 reports various routes to bisulfite adduct, the most efficient of which involved vinyl Grignard addition to 2-indanone followed by ozonolysis and workup with aqueous NaHS0₃ to effect reduction and bisulfite formation in a single pot. The utility of bisulfite adduct is as an aldehyde surrogate in a reductive amination reaction.

[015] The reported methods for the synthesis of ivacaftor suffered from several drawbacks such as harsh conditions, high temperature reactions and use of large excess of polyphosphoric acid and corrosive phosphoryl chloride etc. Furthermore, synthesis of ivacaftor requires use of high performance liquid chromatography (HPLC) techniques for the separation of ivacaftor and their analogues.

[016] Therefore, development of a simple and efficient synthetic route is in urgent need. Accordingly the present inventors developed environmentally benign, cost effective and short synthetic route for the synthesis of ivacaftor and their analogues.

Example 1:

Procedur A:

To a solution of indole acetic acid (500 mg, 2.85 mmol), aniline (2.85 mmol), HOBt (3.4 mmol) in acetonitrile (10 mL), EDC.HCl (3.4 mmol) followed by DIPEA (11.4 mmol) was added, and mixture was stirred for 16 h at ambient temperature. The

reaction mixture was evaporated to dryness, diluted with EtOAc (25 mL), washed with saturated aqueous NaHC0₃ solution (5 mL), H₂0 (5 mL), brine (5 mL), and dried over Na₂S04. The crude material obtained after removal of solvent was purified by column chromatography (silica gel 230-400 mesh, ethyl acetate – pet ether) to afford corresponding amide as a colorless solid.

[040] Example 2:

2-(lH-indol-3-yl)-N-phenylacetamide (1) :

Yield: 570 mg; 80%; 1H NMR (200MHz, DMSO-d₆) δ = 10.95 (brs, 1 H), 10.14 (s, 1 H), 7.64 (d, J = 7.8 Hz, 3 H), 7.47 – 7.24 (m, 4 H), 7.21 – 6.92 (m, 3 H), 3.76 (s, 2H); MS: 273 (M+Na)⁺.

[041] Example 3:

5-(2-(lH-indol-3-yl)acetamido)-2,4-di-tert-butylphenyl methyl carbonate (2): Yield: 800 mg; 64%; 1H NMR (200 MHz, DMSO-d₆) δ = 11.51 (brs, 1 H), 9.41 (s, 1 H), 8.12 (d, J = 7.6 Hz, 1 H), 7.96 – 7.78 (m, 3 H), 7.71 – 7.42 (m, 3 H), 4.34 (s, 3 H), 4.30 (s, 2 H), 1.79 (s, 9 H), 1.64 (s, 9 H); MS: 459 (M+Na)⁺.

[042] Example 4:

(S)-2-(lH-indol-3-yl)-N-(l-phenylethyl)acetamide (3):

Yield: 620 mg; 78%; 1H NMR (400MHz ,DMSO-d₆)5 = 10.88 (brs, 1 H), 8.48 (d, J = 8.1 Hz, 1 H), 7.59 (d, J = 7.8 Hz, 1 H), 7.39 – 7.26 (m, 5 H), 7.25 – 7.16 (m, 2 H), 7.08 (t, J = 7.3 Hz, 1 H), 7.02 – 6.95 (m, 1 H), 4.96 (t, J = 7.3 Hz, 1 H), 3.59 (s, 2H), 1.38 (d, J = 7.1 Hz, 3 H).

[043] Example 5:

N-(4-Fluorophenyl)-2-(lH-indol-3-yl)acetamide (4):

1H NMR (400 MHz, DMSO-d₆) : δ 10.93 (brs, 1H), 10.17 (s, 1H), 7.68 – 7.61 (m, 3H), 7.36 (d, J= 8.1 Hz, 1H), 7.27 (d, J= 2.0 Hz, 1H), 7.15 – 7.13 (m, 3H), 7.11 – 6.99 (m, 1H), 3.73 (s, 2H); ¹³C NMR (100 MHz, DMSO-d₆) : δ 170.1, 159.5, 157.1, 136.6, 136.3, 127.7, 124.4, 121.5, 121.3, 121.2, 119.1, 118.9, 115.8, 115.6, 111.8, 108.9, 34.2; MS: 269 (M+H)⁺

[044] Example 6:

N-(4-Chlorophenyl)-2-(lH-indol-3-yl)acetamide (5):

1H NMR (200 MHz, DMSO-d₆): 510.93 (brs, 1H),10.24 (s, 1H), 7.67 – 7.59 (m, 3H), 7.36 – 7.27 (m, 4H), 7.12 – 6.98 (m, 2H), 3.74 (s, 2H); ¹³CNMR (100 MHz, DMSO-d₆): 5170.4, 138.9, 136.7, 129.1, 127.8, 127.1, 124.5, 121.6, 121.2, 119.2, 119.0, 115.7, 111.9, 108.9, 34.3; MS: 285 (M+H)⁺.

[045] Example 7:

2-(lH-Indol-3-yl)-N-(p-tolyl)acetamide (6) :

1H NMR (400 MHz, DMSO-d₆): 510.91 (brs, 1H), 10.01 (s, 1H), 7.62 (d, J= 7.8 Hz, 1H), 7.50 (d, J= 8.6 Hz, 2H), 7.37 (d, J= 8.1 Hz, 1H), 7.29 – 7.26 (m, 1H), 7.10 – 7.07 (m, 3H), 7.01 – 6.99 (m, 1H), 3.71 (s, 2H), 2.23 (s, 3H); ¹³C NMR (100 MHz, DMSO-de): 5170.0, 137.4, 136.6, 132.4, 129.5, 127.7, 124.3, 121.4, 119.6, 119.2, 118.8, 111.8, 109.1, 34.2, 20.9; MS: 265 (M+H)⁺.

[046] Example 8:

N-(4-Ethylphenyl)-2-(lH-indol-3-yl)acetamide (7):

^XH NMR (400 MHz, DMSO-d₆): 510.91 (brs, 1H), 10.01 (s, 1H), 7.61 (s, 1H), 7.52 (d, J= 8.3 Hz, 2H), 7.36 (d, J= 8.1 Hz, 1H), 7.26 (s, 1H), 7.15 – 7.04 (m, 3H), 6.99 (s, 1H), 2.55 (t, J= 7.5 Hz, 2H), 1.15 (t, J= 7.5 Hz, 3H); ¹³C NMR (100 MHz, DMSO-d₆): 5169.9, 138.9, 137.6, 136.6, 128.3, 127.7, 124.3, 121.4, 119.6, 119.2, 118.8, 111.8, 109.1, 40.6, 40.4, 40.2, 40.0, 39.8, 39.6, 39.4, 34.2, 28.0, 16.2; MS: 279 (M+H)⁺.

[047] Example 9:

2-(lH-Indol-3-yl)-N-(4-propylphenyl)acetamide (8):

1H NMR (400 MHz, DMSO-d₆): 58.48 (brs, 1H), 7.64 (d, J = 8.1 Hz, 1H), 7.50 – 7.42 (m, 2H), 7.33 – 7.15 (m, 6H), 7.07 (d, J= 8.3 Hz, 2H), 3.92 (s, 2H), 2.52 (t, J= 7.6 Hz, 2H), 1.65 – 1.53 (m, 2H), 0.91 (t, J= 7.3 Hz, 3H); ¹³C NMR (100 MHz, DMSO-d₆): 5169.7, 138.9, 136.5, 135.2, 128.8, 126.9, 124.0, 122.8, 120.4, 120.1, 118.7, 111.6, 108.7, 37.4, 34.5, 24.6, 13.7; MS: 315 (M+Na)⁺.

[048] Example 10:

2-(lH-Indol-3-yl)-N-(4-isopropylphenyl)acetamide (9) :

yield 79% ; 1H NMR (400 MHz, DMSO-d₆): δ 10.91 (brs, 1H), 10.01 (s, 1H), 7.62 (d, = 7.8 Hz, 1H), 7.55 – 7.49 (m, = 8.6 Hz, 2H), 7.37 (d, = 8.1 Hz, 1H), 7.26 (d, = 2.0 Hz, 1H), 7.18 – 7.11 (m, = 8.6 Hz, 2H), 7.11 – 7.05 (m, 1H), 7.02 – 6.95 (m, 1H), 2.95 – 2.71 (m, 1H), 1.17 (d, = 6.8 Hz, 6H); ¹³C NMR (100 MHz, DMSO-d₆): δ 169.9, 143.5, 137.6, 136.6, 127.7, 126.8, 124.3, 121.4, 119.7, 119.2, 118.8, 111.8, 109.2, 24.4; MS: 315 (M+Na)⁺.

[049] Example 11:

2-(lH-indol-3-yl)-N-(4-(trifluoromethoxy)phenyl)acetamide (10):

Yield 85% ; 1H NMR (400 MHz, CDC1₃): δ 8.35 (brs., 1 H), 7.44 – 7.38 (m, 2 H), 7.27 – 7.21 (m, 3 H), 7.12 – 7.05 (m, 1H), 7.03 – 6.95 (m, 2H), 6.93 (d, = 8.6 Hz, 2H), 3.75 (s, 2H); ¹³C NMR (100 MHz, CDC1₃): δ 170.0, 145.3, 136.5, 136.2, 126.8, 124.1, 123.0, 121.6, 121.2, 120.5, 118.5, 111.7, 108.2, 34.4; MS: 335 (M+Na)⁺.

[050] Example 12:

N-(2-chloro-5-methoxyphenyl)-2-(lH-indol-3-yl)acetamide (11):

Yield 75% ; ^XH NMR (200 MHz, DMSO-d₆): δ 10.98 (brs, 1H), 9.27 (s, 1H), 7.59 (d, = 7.8 Hz, 1H), 7.53 (d, = 2.9 Hz, 1H), 7.39 – 7.32 (m, 3H), 7.09 – 6.99 (m, 2H), 6.74 (dd, = 3.0, 8.8 Hz, 1H), 3.85 (s, 2H), 3.71 (s, 3H); ¹³C NMR (400 MHz, DMSO-d₆): δ 170.4, 160.1, 141.1, 136.7, 130.0, 127.8, 124.4, 121.6, 119.2, 119.0, 111.9, 109.1, 105.4, 55.4, 34.4; MS: 315 (M+Na)⁺.

[051]Example 13:

N-(2-ethylphenyl)-2-(lH-indol-3-yl)acetamide (12):

Yield 78% ; 1H NMR (400 MHz, CDC1₃): δ 8.68 (brs, 1H), 7.95 (d, = 8.1 Hz, 1H), 7.67 (d, = 7.8 Hz, 1H), 7.48 – 7.44 (m, 2H), 7.29 – 7.23 (m, 1H), 7.22 – 7.20 (m, 3H), 7.05 (d, = 4.4 Hz, 2H), 2.00 (q, = 7.4 Hz, 2H), 0.67 (t, = 7.6 Hz, 3H); ¹³C NMR (100 MHz, CDC1₃): δ 169.9, 136.6, 135.0, 134.3, 128.7, 126.7, 125.1, 124.1, 123.0, 122.5, 120.4, 118.7, 111.6, 108.6, 34.4, 24.2, 13.6.

[052] Example 14:

N-(2-bromophenyl)-2-(lH-indol-3-yl)acetamide(13):

Yield 76%; 1H NMR (200 MHz, DMSO-d₆): δ 11.00 (brs, 1H), 9.30 (s, 1H), 7.81 -7.77 (m, 1H), 7.63 – 7.56 (m, 2H), 7.41 – 7.35 (m, 3H), 7.11 – 7.05 (m, 3H), 3.85 (s, 2H);¹³C NMR (100 MHz, DMSO-d₆): δ 169.9, 136.2, 132.5, 128.0, 127.2, 126.4, 125.5, 124.4, 121.2, 118.7, 118.5, 116.4, 111.4, 108.0, 33.2.

[053] Example 15:

N-benzyl-2-(lH-indol-3-yl)acetamide (14):

Yield 85%; 1H NMR (400 MHz, DMSO-d₆): δ 10.89 (brs., 1H), 8.40 (t, = 5.7 Hz, 1H), 7.57 (d, = 7.8 Hz, 1H), 7.36 (d, = 8.1 Hz, 1H), 7.32 – 7.18 (m, 6H), 7.08 (t, = 7.5Hz, 1H), 7.03 – 6.90 (m, 1H), 4.28 (d, = 5.9Hz, 2H), 3.60 (s, 2H); ¹³C NMR (100 MHz, DMSO-de): δ 171.2, 140.1, 136.6, 128.7, 127.7, 127.2, 124.3, 121.4, 119.2, 118.7, 111.8, 109.3, 42.7, 33.2.

[054] Example 16:

2-(lH-indol-3-yl)-N-(4-methoxybenzyl)acetamide(15):

Yield 85% ; 1H NMR (400 MHz, DMSO-d₆): δ 10.87 (brs, 1 H), 8.32 (t, = 5.6 Hz, 1 H), 7.55 (d, = 7.8 Hz, 1H), 7.35 (d, = 8.1 Hz, 1H), 7.22 – 7.13 (m, 3H), 7.11 – 7.05 (m, 1 H), 7.00 – 6.94 (m, 1H), 6.84 (d, = 8.6 Hz, 2H), 4.20 (d, = 6.1 Hz, 2H), 3.72 (s, 3H), 3.56 (s, 2H); ¹³C NMR (100 MHz, DMSO-d₆): δ 171.1, 158.6, 136.6, 132.0, 129.0, 127.7, 124.2, 121.4, 119.2, 118.7, 114.1, 111.8, 109.4, 55.5, 42.1, 33.2.

[055] Example 17:

N,N-dibenzyl-2-(lH-indol-3-yl)acetamide (16):

Yield 70% ; 1H NMR (400 MHz, DMSO-d₆): δ 10.91 (brs, 1H), 7.50 (d, = 7.8 Hz, 1H), 7.37 – 7.34 (m, 3H), 7.30 (d, = 6.6 Hz, 1H), 7.25 – 7.19 (m, 3H), 7.17 (t, = 6.6 Hz, 5H), 7.16 (d, = 7.8 Hz, 1H), 7.00 – 6.97 (m, 1H), 4.59 (s, 2H), 4.50 (s, 2H), 3.86 (s, 2H); ¹³C NMR (100 MHz, DMSO-d₆): δ 171.7, 138.2, 136.6, 129.2, 128.8, 128.1, 127.8, 127.7, 127.5, 127.1, 124.2, 121.5, 119.2, 118.8, 111.8, 108.5, 50.7, 48.4, 31.2.

[056] Example 18:

2-(lH-indol-3-yl)-N-propylacetamide (17):

Yield 75% ; ^XH NMR (200 MHz, DMSO-d₆): δ 10.86 (brs, 1H), 7.88 – 7.80 (m, 1H), 7.56 (d, = 7.6 Hz, 1H), 7.31 (d, = 7.8 Hz, 1H), 7.17 (d, = 2.3 Hz, 1H), 7.06 – 6.92 (m, 2H), 3.48 (s, 2H), 3.00 (q, J = 6.8 Hz, 2H), 1.39 (sxt, / = 7.2 Hz, 2H), 0.88 – 0.75 (t, = 7.2 Hz, 3H); ¹³C NMR (100 MHz, DMSO-d₆): δ 171.0, 136.6, 127.8, 124.2,

121.4, 119.2, 118.7, 111.8, 109.6, 39.4, 33.3, 22.9, 11.9.

[057] Example 19:

N-hexyl-2-(lH-indol-3-yl)acetamide (18) :

Yield 87% ; 1H NMR (400 MHz, DMSO-d₆): δ 10.84 (brs, 1H), 7.83 (brs, 1H), 7.54 (d, = 7.8 Hz, 1H), 7.33 (d, = 8.1 Hz, 1H), 7.21 – 7.13 (m, 1H), 7.06 (t, = 7.6 Hz, 1H), 6.96 (t, J = 7.5 Hz, 1H), 3.47 (s, 2H), 3.03 (q, / = 6.8 Hz, 2H), 1.37 (t, = 6.5 Hz, 2H), 1.30 – 1.15 (m, 6H), 0.84 (t, = 6.7 Hz, 3H); ¹³C NMR (100 MHz, DMSO-d₆): δ 170.9, 136.6, 127.7, 124.2, 121.3, 119.1, 118.7, 111.7, 109.5, 39.06, 33.2, 31.5, 29.6, 26.5, 22.5, 14.4.

[058] Example 20:

Methyl (2-(lH-indol-3-yl)acetyl)-L-alaninate (19):

Yield 79% ; 1H NMR (400 MHz, CDC1₃): δ 8.53 (brs, 1H), 7.60 (d, = 7.8 Hz, 1H), 7.41 (d, = 8.1 Hz, 1H), 7.25 – 7.23 (m, 1H), 7.19 – 7.14 (m, 2H), 6.27 (d, = 7.3 Hz, 1H), 4.63 (t, = 7.3 Hz, 1H), 3.78 (s, 2H), 3.68 (s, 3H), 1.31 (d, = 7.3 Hz, 3H); ¹³C NMR (100 MHz, CDC1₃): δ 173.4, 171.2, 136.4, 127.0, 123.8, 122.5, 119.9, 118.7,

111.5, 108.5, 52.4, 48.0, 33.3, 18.2.

[059] Example 21:

-(6-chloro-lH-indol-3-yl)-N-phenylacetamide(20):

To a solution of 6-Chloro indole 20a (300 mg, 1.98 mmol )in anhydrous THF, Oxalyl chloride (186 μΤ, 276 mg, 2.18 mmol) was added and the mixture stirred at room temperature. After 2 h, N,N-Diisopropylethylamine (758 μΤ, 562 mg, 4.35 mmol) was

introduced to the mixture, followed by the aniline (221.0 mg, 2.37 mmol). The temperature was raised to 45 °C, and heating continued for 18 h. The solvent was evaporated, and then mixture was diluted with EtOAC (15 mL), washed with brine and dried over anhydrous Na₂S0₄. The crude material obtained after removal of solvent was purified by column chromatography (10 – 20% EtOAc : Petroleum ether) to afford 20b (295 mg, 51% yield) as a yellow coloured solid. IR O_max(film): 3346, 3307,2853, 1724, 1678 cm^“1; 1H NMR (400 MHz, DMSO-d₆): δ 12.40 (br. s., 1H), 10.68 (s, 1H), 8.79 (d, = 3.2 Hz, 1H), 8.25 (d, = 8.6 Hz, 1H), 7.85 (d, = 7.8 Hz, 2H), 7.62 (d, = 1.7 Hz, 1H), 7.41 – 7.30 (m, 3H), 7.19 – 7.13 (m, 1H); ¹³C NMR (100 MHz, DMSO-d₆): δ 182.5, 162.5, 140.0, 138.4, 137.4, 129.2, 128.5, 125.4, 124.8, 123.4, 122.9, 120.8, 113.0, 112.3; HRMS (ESI) Calculated for Ci₆HnN₂OCl[M+H]⁺: 299.0582, found 299.0580;

A solution of 20b (300 mg, 0.99 mmol) dissolved in MeOH (40 mL) was added to NaBH₄ (45 mg, 1.23 mmol). The reaction was stirred for 4h and then added to saturated solution of Na₂S0₄. The reaction mixture was further stirred for lh and then filtered through Celite.The filtrate obtained was concentrated in vacuo, and then mixture was diluted with EtOAc (15 mL), washed with brine and dried over anhydrous Na₂S0₄. The crude material obtained after removal of solvent was forwarded for next step without further purification.In an N₂ atmosphere, TMSC1 (1.272 mL, 9.9 mmol) in CH₃CN (40 mL) was added to sodium iodide (1.488 mg, 9.9 mmol) and stirred for 2h. The reaction mixture was cooled to 0 °C and a solution of above crude alcohol (0.99 mmol) in CH₃CN (10 mL) was then added drop wise over 30 min, followed by stirring for 3h. The reaction mixture was poured into NaOH (7g in 40 mL of water) and then extracted with ethyl acetate (15×2). The organic layer was washed with aq.Na₂S₂0₃, dried over Na₂S0₄ and concentrated in vacuo. The residue was chromatographed on silica gel (EtOAc:Pet ether) to afford 20 as a off white solid (two steps 38 % ); IR Umax(film): 3273, 3084,2953, 2857, 1629, 1562 cm^“1; 1H NMR (400 MHz, DMSO-d₆): δ 11.06 (br. s., 1H), 10.13 (br. s., 1H), 7.62 – 7.57 (m, 3H), 7.40 (s, 1H), 7.30 – 7.25 (m, 3H), 7.04 – 6.99 (m, 2H), 3.71 (s, 2H); ¹³C NMR (100 MHz, DMSO-d₆): δ 170.1,

139.7, 136.9, 129.2, 126.5, 126.3, 125.5, 123.7, 120.6, 119.6, 119.3, 111.5, 109.4, 34.0; HRMS (ESI):Calculated for Ci₆Hi₄N₂OCl[M+H]⁺: 285.0789, found 285.0786.

[060] Example 22:

2-(5-chloro-lH-indol-3-yl)-N-phenylacetamide(21):

21a 21b 21

To a solution of 5-Chloro indole 21a (300 mg, 1.98 mmol )in anhydrous THF(20 mL), Oxalyl chloride (186 ^L, 276 mg, 2.18 mmol) was added and the mixture stirred at room temperature. After 2 h, N,N-diisopropylethylamine (758 μΕ, 562 mg, 4.35 mmol) was introduced to the mixture, followed by the aniline (221.0 mg, 2.37 mmol). The tempera ture was raised to 45 °C, and heating continued for 18 h. The solvent was evaporated, and then mixture was diluted with EtOAC (15 mL), washed with brine and dried over anhydrous Na₂S04. The crude material obtained after removal of solvent was purified by column chromatography (10 – 20% EtOAc : Petroleum ether) to afford (21b) (305 mg, 53% yield) as a yellow coloured solid. IR rj_max(film): 3346, 3307,2853, 1724, 1678 cm^“1; 1H NMR (400 MHz, DMSO-d₆): δ 12.40 (br. s., 1H), 10.68 (s, 1H), 8.79 (d, = 3.2 Hz, 1H), 8.25 (d, = 8.6 Hz, 1H), 7.85 (d, = 7.8 Hz, 2H), 7.62 (d, = 1.7 Hz, 1H), 7.42 – 7.30 (m, 3H), 7.20 – 7.14 (m, 1H); ¹³C NMR (100 MHz, DMSO-d₆): δ 182.4, 162.4, 140.3, 138.4, 135.4, 129.2, 127.9, 124.8, 124.1, 120.8, 114.8, 112.0; HRMS (ESI) Calculated for Ci₆HnN₂OCl[M+H]⁺: 299.0582, found 299.0580; A solution of 21b (200 mg, 0.66 mmol) dissolved in MeOH (30 mL) was added to NaBH₄ (30 mg, 0.82 mmol). The reaction was stirred for 4h and then added to saturated solution of Na₂S0₄. The reaction mixture was further stirred for lh and then filtered through Celite. The filtrate obtained was concentrated in vacuo, and then mixture was diluted with EtOAc (15 mL), washed with brine and dried over anhydrous Na₂S0₄. The crude material obtained after removal of solvent was forwarded for next step without further purification. In an N₂ atmosphere, TMSC1 (848 mL, 6.6 mmol) in CH₃CN (25 mL) was added to sodium iodide (992 mg, 6.6 mmol) and stirred for 2h. The reaction mixture was cooled to 0 °C and a solution of above crude alcohol(0.66 mmol) in CH₃CN (5 mL) was then added dropwise over 30 min, followed by stirring for 3h. The reaction mixture was poured into NaOH (5g in 30 mL of water) and then extracted with ethyl acetate(15×2). The organic layer was washed with aq.Na₂S₂0₃, dried over Na₂S0₄ and concentrated in vacuo. The residue was chromatographed on silica gel (EtOAc:Pet ether) to afford 22 as a off white solid (two steps 42 % ); IR Umax(film): 3273, 3084,2955, 2857, 1629, 1562 cm^“1; 1H NMR (400 MHz, DMSO-d₆): δ 11.13 (br. s., 1H), 10.11 (s, 1H), 7.67 (s, 1H), 7.60 (d, = 7.8 Hz, 2H), 7.39 – 7.27 (m, 4H), 7.13 – 7.02 (m, 2H), 3.16 (s, 2H); ¹³C NMR (100 MHz, DMSO-d₆): δ 169.9, 139.8, 135.0, 129.2, 128.9, 126.2, 123.6, 121.4, 119.6, 118.6, 113.4, 109.0, 34.0; HRMS (ESI) Calculated for Ci₆H₁₄N₂OCl[M+H]⁺: 285.0789, found 285.0786.

[061] Example 23:

2-(l-benzyl-lH-indol-3-yl)-N-phenylacetamide (22):

Yield 79% ; 1H NMR (400 MHz, DMSO-d₆): δ 7.67 (d, = 7.8 Hz, 1H), 7.54 (brs, 1H), 7.43 – 7.31 (m, 6H), 7.31 – 7.25 (m, 3H), 7.23 – 7.15 (m, 4H), 7.12 – 7.06 (m, 1H), 5.36 (s, 2H), 3.91 (s, 2H); ¹³C NMR (100 MHz, DMSO-d₆): δ 169.7, 137.7, 137.2, 137.0, 128.9, 128.9, 127.9, 127.6, 126.9, 124.3, 122.7, 120.2, 119.9, 119.0, 110.2, 107.9, 77.4, 77.1, 76.8, 50.1, 34.5.

[062] Example 24:

Procedure B:

2-(lH-indol-3-yl)-N-phenylacetamidel(100 mg; 0.4 mmol) was dissolved in DCM:MeOH(50 mL; 5: 1), then a stream of 0₃ was passed through the solution until a blue color developed (10 min). The 0₃ stream was continued for 4 min. Then surplus O3 was removed by passing a stream of 0₂ through the solution for 10 min or until the blue colorcompletely vanished. Afterwards pyridine (0.1 mL;1.2mmol) was added to the cold (- 78 °C) mixture. The mixture was allowed to warm to room temperature (1 h) and then Et₃N (0.35 mL; 2.4 mmol) were added. After stirring at room temperature overnight the reaction mass was concentrated under reduced pressure to dryness, diluted with EtOAc (30 mL), washed with H₂0 (5 mL), brine (5 mL), and dried over Na₂S0₄. The crude material obtained after removal of solvent was purified by column chromatography (silica gel 230-400 mesh, MeOH – DCM) to give desired quinolone carboxamide as colorless solid.

[063] Example 25:

4-oxo-N-phenyl-l,4-dihydroquinoline-3-carboxamide (23):

Yield: 65 mg; 62%; ^XH NMR (200MHz ,DMSO-d₆) δ = 12.97 (brs, 1 H), 12.49 (s, 1 H), 8.89 (s, 1 H), 8.33 (d, J = 8.2 Hz, 1 H), 7.91 – 7.69 (m, 4 H), 7.62 – 7.50 (m, 1 H), 7.37 (t, J = 7.8 Hz, 2 H), 7.18 – 7.01 (m, 1 H); MS: 287 (M+Na)⁺.

[064] Example 26:

2,4-di-tert-butyl-5-(4-oxo-l,4-dihydroquinoline-3-carboxamido)phenyl methyl carbonate (24):

Yield: 35 mg; 34%; 1H NMR (400MHz ,DMSO-d₆) δ = 12.96 (brs, 1 H), 12.08 (s, 1 H), 8.94 – 8.82 (m, 1 H), 8.44 – 8.28 (m, 1 H), 7.86 – 7.79 (m, 1 H), 7.78 – 7.73 (m, 1 H), 7.59 (s, 1 H), 7.53 (t, J = 7.5 Hz, 1 H), 7.39 (s, 1 H), 3.86 (s, 3 H), 1.46 (s, 9 H), 1.32 (s, 9 H).

[065] Example 27:

(S)-4-oxo-N-(l-phenylethyl)-l,4-dihydroquinoline-3-carboxamide (25):

Yield: 56 mg; 53%; 1H NMR (500MHz ,DMSO-d₆) δ = 12.75 (brs, 1H), 10.54 (d, J = 7.6 Hz, 1H), 8.73 (brs, 1H), 8.28 (d, J = 7.9 Hz, 1H), 7.78 (d, J = 7.9 Hz, 1H), 7.73 -7.68 (m, 1 H), 7.50 (t, J = 7.5 Hz, 1 H), 7.42 – 7.34 (m, 4 H), 7.29 – 7.23 (m, 1 H), 5.18 (t, J = 7.2 Hz, 1 H), 1.50 (d, J = 6.7 Hz, 3 H).

[066] Example 28:

Synthesis of ivacaftor (26):

To a solution of 2,4-di-tert-butyl-5-(4-oxo-l,4-dihydroquinoline-3-carboxamido)phenyl methyl carbonate 5 (30 mg, 0.06mmol) in MeOH (2 mL) was added NaOH (5.3 mg, 0.13mmol) dissolved in H₂0 (2 mL), and the reaction mixture was stirred at room temperature for 5h. Reaction mass was evaporated to one third of its volume (temperature not exceeding 40°C) and acidified with aq.2N HC1 to pH 2-3. The resulting precipitate was collected by suction filtration give desired compound 7 (19 mg, 76%) as off white solid H NMR (400MHz ,DMSO-d₆) δ = 12.88 (d, J = 6.6 Hz, 1 H), 11.81 (s, 1 H), 9.20 (s, 1 H), 8.86 (d, J = 6.6 Hz, 1 H), 8.32 (d, J = 7.8 Hz, 1 H), 7.88 – 7.65 (m, 2 H), 7.51 (t, J = 7.5 Hz, 1 H), 7.16 (s, 1 H), 7.10 (s, 1 H), 1.38 (s,9H), 1.36 (s, 9H).

[067] Example 29:

N-(4-fluorophenyl)-4-oxo-l,4-dihydroquinoline-3-carboxamide (27):

Yield 56% ; 1H NMR (400 MHz, DMSO-d₆): δ 12.96 (br. s., 1H), 12.50 (s, 1H), 8.88 (s, 1H), 8.33 (d, = 7.3 Hz, 1H), 7.86 – 7.72 (m, 4H), 7.54 (t, = 7.3 Hz, 1H), 7.20 (t, = 8.8 Hz, 2H); ¹³C NMR (400 MHz, DMSO-d₆): δ 176.8, 163.2, 159.7, 157.3, 144.6, 139.6, 135.7, 133.5, 126.4, 125.9, 125.8, 121.8, 119.7, 116.1, 115.9, 110.9.

[068] Example 30:

N-(4-chlorophenyl)-4-oxo-l,4-dihydroquinoline-3-carboxamide (28):

Yield 51% ; 1H NMR (400 MHz, DMSO-d₆): δ 13.00 (brs., 1H), 12.59 (br. s., 1H), 8.89 (s, 1H), 8.34 (d, = 7.6 Hz, 1H), 7.83 – 7.76 (m, 4H), 7.56 (s, 1H), 7.42 (d, = 7.9 Hz, 2H); ¹³C NMR (400 MHz, DMSO-d₆): δ 176.8, 163.4, 144.7, 139.6, 138.2, 133.5, 129.4, 127.4, 126.4, 125.9, 125.8, 121.6, 119.7, 110.8.

[069] Example 31:

4-oxo-N-(p-tolyl)-l,4-dihydroquinoline-3-carboxamide (29):

Yield 57% ; 1H NMR (400 MHz, DMSO-d₆): δ 12.94 (brs., 1H), 12.40 (s, 1H), 8.88 (s, 1H), 8.33 (d, = 7.8Hz, 1H), 7.82 – 7.80 (m, 1H), 7.76 – 7.7 (m, 1H), 7.63 (d, = 8.3 Hz, 2H), 7.53 (t, = 7.3 Hz, 1H), 7.17 (d, = 8.1 Hz, 2H), 2.29 (s, 3H); ¹³C NMR (100 MHz, DMSO-de): δ 176.8, 163.1, 144.5, 139.6, 136.8, 133.4, 132.8, 129.9, 126.4, 125.9, 125.7, 120.0, 119.6, 111.1, 20.9; HRMS (ESI):Calculated for Ci₇H₁₅0₂N₂[M+H]⁺: 279.1128, found 279.1127.

[070] Example 32:

N-(4-ethylphenyl)-4-oxo-l,4-dihydroquinoline-3-carboxamide (30):

Yield 51% ; 1H NMR (400 MHz, DMSO-d₆): δ 12.95 (br. s., 1H), 12.40 (d, = 7.8 Hz, 1H), 8.87 (d, = 6.1 Hz, 1H), 8.33 (d, = 8.1 Hz, 1H), 7.81 – 7.76 (m, 2H), 7.66 – 7.62 (m, = 8.3 Hz, 2H), 7.53 (t, 7 = 7.5 Hz, 1H), 7.22 – 7.17 (m, = 8.3 Hz, 2H), 2.58 (q, = 7.6 Hz, 2H), 1.18 (t, = 7.6 Hz, 3H); ¹³C NMR (400 MHz, DMSO-d₆): δ 181.5, 167.8, 149.3, 144.3, 144.0, 141.7, 138.2, 133.4, 131.1, 130.7, 130.5, 124.8, 124.4, 115.9, 32.8, 20.9.

[071] Example 33:

4-Oxo-N-(4-propylphenyl)-l,4-dihydroquinoline-3-carboxamide (31):

Yield 51%; 1H NMR (500 MHz, DMSO-d6): δ12.93 (brs, 1H), 12.40 (s, 1H), 8.87 (s, 1H), 8.36 – 8.29 (m, 1H), 7.86 – 7.78 (m, 1H), 7.75 (d, J= 7.9 Hz, 1H), 7.68 – 7.61 (m, J= 8.2 Hz, 2H), 7.54 (t, J= 7.6 Hz, 1H), 7.22 – 7.14 (m, J= 8.2 Hz, 2H), 2.55 – 2.51 (m, 2H), 1.64 – 1.53 (m, 2H), 0.90 (t, J= 7.3 Hz, 3H); ¹³C NMR (500 MHz, DMSO-d6): 176.8, 163.1, 144.5, 139.6, 137.6, 137.0, 133.5, 129.3, 126.4, 125.9, 125.7, 120.0, 119.7, 111.1, 37.2, 24.6, 14.1.

[072] Example 34:

N-(4-isopropylphenyl)-4-oxo-l,4-dihydroquinoline-3-carboxamide (32):

Yield 46% ; 1H NMR (500 MHz, DMSO-d₆): δ 12.93 (br. s., 1H), 12.40 (br. s., 1H), 8.89 – 8.86 (m, 1H), 8.33(d, = 7.6 Hz, 1H), 7.81 – 7.50 (m, 5H), 7.25 – 7.21 (m, 2H), 2.90-2.83 (m, 1H), 1.22-1. l l(m, 6H); ¹³C NMR (100 MHz, DMSO-d₆): δ 176.8, 163.1, 144.5, 143.9, 139.6, 137.1, 133.4, 127.2, 126.4, 125.9, 125.7, 120.1, 119.6, 111.1, 33.4, 24.4.

[073] Example 35:

4-oxo-N-(4-(trifluoromethoxy)phenyl)-l,4-dihydroquinoline-3-carboxamide(33):

Yield 57% ; 1H NMR (400 MHz, DMSO-d₆): δ 12.98 (br. s., 1H), 12.63 (s, 1H), 8.88 (d, = 4.9 Hz, 1H), 8.32 (d, = 7.8 Hz, 1H), 7.89 – 7.83 (m, = 8.8 Hz, 2H), 7.79 (d, = 7.6 Hz, 1H), 7.77 – 7.73 (m, 1H), 7.53 (t, J = 7.5 Hz, 1H), 7.40 – 7.34 (m, = 8.6 Hz, 2H); ¹³C NMR (100 MHz, DMSO-d₆): δ 176.8, 163.5, 144.7, 144.0, 139.5, 138.5, 133.5, 126.3, 125.9, 125.8, 122.3, 121.4, 119.7, 110.7.

[074] Example 36:

N-(2-chloro-5-methoxyphenyl)-4-oxo-l,4-dihydroquinoline-3-carboxamide(34):

Yield 54% ; ^XH NMR (400 MHz, DMSO-d₆): δ 12.98 (br. s., 1H), 12.49 (s, 1H), 8.88 (s, 1H), 8.33 (d, = 7.8 Hz, 1H), 7.83 – 7.75 (m, 1H), 7.56-7.48 (m, 3H), 7.27 – 7.21 (m, 1H), 6.67 (d, = 7.8 Hz, 1H), 3.77 (s, 3H); ¹³C NMR (400 MHz, DMSO-d₆): δ 176.8, 163.4, 160.2, 144.7, 140.4, 139.6, 133.5, 130.3, 126.4, 125.9, 125.8, 119.7, 112.3, 111.0, 109.5, 105.7, 55.5.

[075] Example 37:

N-(2-ethylphenyl)-4-oxo-l,4-dihydroquinoline-3-carboxamide(35):

Yield 58% ; 1H NMR (400 MHz, DMSO-d₆): δ 12.94 (br. s., 1H), 12.37 (s, 1H), 8.90 (s, 1H), 8.36 (dd, = 8.1, 1.4 Hz, 2H), 8.32 (dd, = 8.1, 1.4 Hz, 2H), 7.82 – 7.74 (m, 1H), 7.53- 7.19 (m, 3H), 7.15 – 7.06(m, 1H), 2.79 (q, = 7.3 Hz, 2H), 1.26 (t, = 7.5 Hz, 3H); 293 (M+H)⁺.

[076] Example 38:

N-(2-bromophenyl)-4-oxo-l,4-dihydroquinoline-3-carboxamide(36):

Yield 47% ; 1H NMR (200 MHz, DMSO-d₆): δ 12.98 (br. s., 1H), 12.69 (s, 1H), 8.90 (d, = 5.9 Hz, 1H), 8.54 (dd, 7 = 1.4, 8.3 Hz, 1H), 8.34 (d, = 7.6 Hz, 1H), 7.86 – 7.67 (m, 3H), 7.57 – 7.49 (m, 1H), 7.40 (t, = 7.2 Hz, 1H), 7.10 – 7.05 (m, 1H); ¹³C NMR (100 MHz, DMSO-de): δ 176.7, 163.7, 145.0, 139.5, 137.7, 133.5, 133.1, 128.6, 126.4, 126.0, 125.8, 125.3, 122.9, 119.7, 113.4, 110.8.

[077] Example 39:

N-benzyl-4-oxo-l,4-dihydroquinoline-3-carboxamide(37):

Yield 58% ; 1H NMR (400 MHz, CD₃OD-d₆): δ 8.82 (s, 1 H), 8.35 (d, = 8.1 Hz, 1 H), 7.79 – 7.77 (m, 1 H), 7.65 (d, = 8.3 Hz, 1 H), 7.52 (t, = 7.6 Hz, 1 H), 7.42 – 7.34 (m, 4 H), 7.31 – 7.26 (m, 1 H), 4.67 (s, 2 H); ¹³C NMR (400 MHz, DMSO-d₆): δ 176.6, 165.0, 144.2, 140.0, 139.5, 133.2, 128.9, 128.7, 127.8, 127.3, 126.6, 125.9, 125.4, 119.5, 111.2, 42.6.

[078] ] Example 40:

N-(4-methoxybenzyl)-4-oxo-l,4-dihydroquinoline-3-carboxamide(38):

Yield 56% ; 1H NMR (400 MHz, DMSO-d₆): δ 12.73 (br. s., 1H), 10.35 (t, = 5.3 Hz, 1H), 8.78 (d, = 6.1 Hz, 1H), 8.24 (d, = 8.1 Hz, 1H), 7.76 (d, = 7.1 Hz, 1H), 7.73 -7.68 (m, 1H), 7.48 (t, = 7.5 Hz, 1H), 7.28 (d, = 8.3 Hz, 2H), 6.91 (d, = 8.1 Hz, 2H), 4.49 (d, = 5.6 Hz, 2H), 3.74 (s, 3H); ¹³C NMR (100 MHz, DMSO-d₆): δ 176.6, 164.8, 158.8, 144.1, 139.5, 133.1, 131.9, 129.2, 126.6, 125.8, 125.4, 119.5, 114.3, 111.3, 55.5, 42.0.

[079] Example 41:

N,N-dibenzyl-4-oxo-l,4-dihydroquinoline-3-carboxamide(39):

Yield 43% ; 1H NMR (400 MHz, DMSO-d₆): δ 12.21 (br. s., 1H), 8.27 (d, = 4.9 Hz, 1H), 8.21 (d, = 7.6 Hz, 1H), 7.49 – 7.41 (m, 2H), 7.41 – 7.35 (m, 3H), 7.33 – 7.20 (m, 5H), 7.20 – 7.11 (m, 7 = 7.1 Hz, 2H), 4.59 (br. s., 2H), 4.42 (s, 2H).

[080] Example 42:

4-oxo-N-propyl-l,4-dihydroquinoline-3-carboxamide(40):

Yield 47% ;1H NMR (400 MHz, DMSO-d₆): δ 12.7 (br.s., 1H)10.05 (t, = 5.5 Hz, 1H), 8.74 (s, 1H), 8.26 (d, = 8.1 Hz, 1H), 7.83 – 7.66 (m, 2H), 7.52 – 7.44 (m, 1H), 3.33 – 3.22 (m, 2H), 1.61 – 1.49 (m, 2H), 0.93 (t, = 7.5 Hz, 3H); ¹³C NMR (100 MHz, DMSO-de): δ 176.6, 164.8, 143.9, 139.5, 133.1, 126.6, 125.9, 125.3, 119.4, 111.4, 39.3, 23.1, 12.0

[081] Example 43:

N-hexyl-4-oxo-l,4-dihydroquinoline-3-carboxamide(41):

Yield 51% ;1H NMR (400 MHz, DMSO-d₆): δ 12.68 (m, 1H), 10.02 (t, = 5.5 Hz, 1H), 8.73 (d, = 6.1 Hz, 1H), 8.27 – 8.25 (m, 1H), 7.77 – 7.67 (m, 2H), 7.47 (t, = 7.5 Hz, 1H), 3.33 – 3.29 (m, 2H), 1.56 – 1.45 (m, 2H), 1.34 – 1.25 (m, 6H), 0.88 – 0.82 (m, 3H); ¹³C NMR (100 MHz, DMSO-d₆): δ 176.6, 164.8, 143.9, 139.5, 133.1, 126.6, 125.9, 125.3, 119.4, 111.4, 38.7, 31.5, 29.8, 26.7, 22.5, 14.4.

[082] Example 44:

Methyl (4-oxo-l,4-dihydroquinoline-3-carbonyl)-L-alaninate(42):

Yield 38% ; 1H NMR (400 MHz, CD₃OD): δ 8.74 (s, 1H), 8.47 – 8.29 (m, 1H), 7.86 -7.76 (m, 1H), 7.64 (d, = 8.3 Hz, 1H), 7.58 – 7.44 (m, 1H), 4.69 (d, = 7.3 Hz, 1H), 3.79 (s, 3H), 1.55 (d, = 7.3 Hz, 3H); ¹³C NMR (100 MHz, CD₃OD): δ 177.3, 173.3, 165.5, 143.6, 139.2, 132.9, 126.3, 125.4, 125.2, 118.5, 110.3, 51.5, 47.0, 17.0.

[083] Example 45:

7-chloro-4-oxo-N-phenyl-l,4-dihydroquinoline-3-carboxamide(43):

Yield 48% ; IR O_max(film): 2920, 2868, 1661, 1601 cm^{” 1;} 1H NMR (400 MHz, DMSO-de): δ 12.91 (br. s., 1H), 12.30 (s, 1H), 8.90 (s, 1H), 8.29 (d, = 8.8 Hz, 1H), 7.80 -7.67 (m, 3H), 7.58 – 7.51 (m, 1H), 7.36 (t, = 7.7 Hz, 2H), 7.09 (t, = 7.3 Hz, 1H); ¹³C NMR (100 MHz, DMSO-d₆): δ 176.3, 162.9, 145.4, 140.3, 139.2, 138.0, 129.5, 128.2, 126.1, 125.1, 123.9, 120.1, 118.8, 111.6.

[084] Example 46:

6-chloro-4-oxo-N-phenyl-l,4-dihydroquinoline-3-carboxamide(44):

Yield 52% ; 1H NMR (400 MHz, DMSO-d₆): δ 13.05 (brs, 1H), 12.27 (s, 1H), 8.88 (s, 1H), 8.21 (d, = 2.2 Hz, 1H), 7.86 – 7.67 (m, 4H), 7.36 (t, = 7.8 Hz, 2H), 7.16 – 7.04 (m, 1H); ¹³C NMR (100 MHz, DMSO-d₆): δ 175.6, 162.9, 144.9, 139.1, 138.2, 133.5, 130.4, 129.5, 127.5, 124.9, 123.9, 122.0, 120.1, 111.4.

[085] Example 47:

l-benzyl-4-oxo-N-phenyl-l,4-dihydroquinoline-3-carboxamide(45)

Yield 55% ; 1H NMR (400 MHz, DMSO-d₆): δ 12.30 (s, 1H), 9.05 (s, 1H), 8.60 (dd, = 1.7, 8.1 Hz, 1H), 7.82 (d, = 7.8 Hz, 2H), 7.69 – 7.62 (m, 1H), 7.55 – 7.45 (m, 2H), 7.43 – 7.34 (m, 5H), 7.24 – 7.18 (m, 2H), 7.17 – 7.10 (m, 1H), 5.53 (s, 2H); ¹³C NMR (100 MHz, DMSO-d₆): δ 176.9, 162.9, 148.7, 139.3, 138.7, 134.1, 133.1, 129.4, 128.9, 128.7, 128.0, 127.4, 126.2, 125.5, 123.9, 120.5, 116.9, 112.3, 57.9; HRMS (ESI): Calculated for C₂₃H₁₈0₂N₂Na [M+Na]⁺: 377.1260, found 377.1259; MS: 355 (M+H)⁺.

[086] Advantages of invention:

1. Cost-effective process for synthesis.

2. Carried out at environmentally benign conditions.

3. Short synthetic route.

4. Useful for making several related compounds of medicinal

Image result for REDDY SRINIVASA DUMBALA

DR SRINIVASA REDDY recieving NASI – Reliance Industries Platinum Jubilee Award (2015) for Application Oriented Innovations in Physical Sciences.

Image result for REDDY SRINIVASA DUMBALA

MYSELF WITH HIM

Image result for REDDY SRINIVASA NCL

From left to right: Dr. D. Srinivasa Reddy, Shri Y. S. Chowdary, Dr. Harsh Vardhan, Dr. Girish Sahni

Dr D. Srinivasa Reddy receiving the prestigious “SHANTI SWARUP BHATNAGAR” award at the occasion of the 75th Foundation day of CSIR.

Shanti Swarup Bhatnagar awardees with the honorable Prime Minister of India

Image result for REDDY SRINIVASA NCL

NCL PUNE

DSR Group

//////////WO-2016181414, WO 2016181414, IVACAFTOR, new patent, COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH, Anusandhan Bhawan, Rafi Marg New Delhi, INDIA, CSIR, Dr. D. Srinivasa Reddy

Diacerein, US 8324411

PATENTS Comments Off

Sep 022016

Patent US 8324,411

https://www.google.com/patents/US8324411

Inventors	Annibale Salvi, Antonio Nardi, Stefano Maiorana, Mara Sada
Original Assignee	Laboratorio Chimico Internazionale S.P.A.

Laboratorio Chimico Internazionale s.p.A., Milan, Italy

Diacerein, 20a, is used in the treatment of arthritis, and there are several methods available for its synthesis. The majority of these are said to involve an oxidation step that uses CrO₃, and as a result, extensive purification is required to remove residues of Cr and reaction byproducts. The patent discloses an oxidation procedure in the preparation of 20a that avoids these problems and is claimed to be suitable for industrial production. Scheme 8 shows the route used to prepare 20athat starts with formation of the protected quinone, 19b. Despite the workup of the compound being quite lengthy, 19b is isolated in 74% yield with 98% purity. The next step is oxidation of the protected dihydroxy quinone 19b using TEMPO and an alkaline chlorite plus an alkaline hypochlorite. The chlorite is used in around 2 mol excess of the substrate and the hypochlorite at around 5 mol % of the substrate. After the oxidation the crude product is isolated in 98% yield and then purified by treatment with Et₃N and DMF. The purified 20b is obtained in 76% yield, and then the protection is removed using FeCl₃/Ac₂O. The yield of crude 20a is 92%, and it is said to be purified by known techniques. The Cr content of the purified material is reported as <1 ppm, and genotoxic impurities such as 19a or acetyl derivatives are reported to be <2 ppm.

Scheme 8. ^a

^aReagents and conditions: (a) (i) K₂CO₃, KI, Bu₄NBr, DMF, 60 °C; (ii) 80 °C, 1 h; (iii) BnCl, 50 °C, 1 h; (iv) 80 °C, 1 h; (v) add MeOH at 50 °C; (vi) cool to <25 °C, filter; (vii) evaporate, add THF; (viii) wash at 60 °C with aq NaOH, H₂O, brine; (ix) evaporate, add EtOAc, concentrate; (x) cool <4 °C, 1 h; (xi) filter, wash, dry. (b) (i) TEMPO, aq NaH₂PO₄, aq Na₂HPO₄, MeCN, 35 °C; (ii) add aq NaClO₂, 35 °C, 50 min; (iii) add aq NaOCl, 65 °C, 3 h; (iv) cool rt, add H₂O; (v) add H₃PO₄, pH 3; (vi) filter, H₂O wash, dry; (vii) Et₃N, DMF, EtOAc, 60 °C, 0.5 h; (viii) filter hot; (ix) add H₂O, separate; (x) extract H₂O phase at 60 °C with EtOAc (×6); (xi) cool organic phases to rt, add HCl to pH 2; (xii) cool <5 °C, 1 h; (xiii) filter, H₂O wash, MeCN wash, dry. (c) (i) FeCl₃, Ac₂O, 65 °C, 1.5 h; (ii) cool <4 °C, 1 h; (iii) filter, wash in Ac₂O, EtOAc wash, dry.

Advantages

The process produces the desired product without using heavy-metal oxidising agents; however, the workup procedures are quite lengthy.

Example 1 Preparation of 1,8-dibenzyloxy-3-(hydroxymethyl)anthraquinone (dibenzyl aloe-emodin)483 g (3.5 moles) of potassium carbonate, 16 g (0.1 moles) of potassium iodide and 16 g (0.05 moles) of tetrabutylammonium bromide are added to a solution of 270 g (1 mole) of 1,8-dihydroxy-3-(hydroxymethyl)anthraquinone (aloe-emodin) in 3500 ml of DMF at 60° C.; the reaction mixture is heated at 80° C. for 1 h. It is cooled to 50° C. and 443 g (3.5 moles) of benzyl chloride are added dropwise in approximately one hour. At the end of the dripping, the reaction mixture is brought back to 80° C. and left at that temperature under stirring for 45-60 minutes. It is then cooled to 50° C. and 200 ml of methyl alcohol are added. It is cooled to 20-25° C. and the inorganic salts are removed by filtering. The organic solvent is distilled at 60-70° C. at reduced pressure and the residue is dissolved in 3200 ml of tetrahydrofuran at 60° C. Maintaining the temperature at 50-60° C., the organic phase is washed twice with 1200 ml of 2.5 molar aqueous sodium hydroxide and once with 1000 ml of a saturated solution of sodium chloride in water. The organic phase is concentrated at reduced pressure at 60° C. and the residue is recovered with 2700 ml of ethyl acetate. The suspension thus obtained is concentrated to approximately ⅓ of the initial volume by distillation of the solvent at reduced pressure. It is gradually cooled to 0-4° C. and kept at that temperature for 1 hour. The solid is filtered and washed with ethyl acetate (100 ml×2). The damp product is dried at 45° C. at reduced pressure for 12-14 hours, providing 334 g (yield 74%) of dibenzyl aloe-emodin having a purity of 98% (HPLC).

melting point: 170-171° C.

IR cm⁻¹: 1655, 1612, 1232

Example 2 Synthesis of 1,8-dibenzyloxyanthraquinone-3-carboxylic acid (dibenzylrhein)10 g (0.06 moles) of radical 2,2,6,6-tetramethyl-1-piperidinyl-oxyl (TEMPO) and 1160 ml of an aqueous solution of 120 g (1 mole) of sodium dihydrogen phosphate and 180 g (1 mole) of disodium hydrogen phosphate are added in sequence to a suspension of 333 g (0.74 moles) of 1,8-dibenzyloxy-3-(hydroxymethyl)anthraquinone in 1660 ml of acetonitrile. The reaction mixture is heated to 35° C. and a solution of 167 g (1.5 moles) of sodium chlorite 80% in 513 ml of water is added dropwise in 40-50 minutes, maintaining the temperature around 35-40° C. 20 ml of aqueous sodium hypochlorite 10-12% are then dripped in and the reaction is heated to 60-65° C. for three hours. It is cooled to room temperature and 1400 ml of water are added. Phosphoric acid 85% is dripped in until reaching a pH of 2.8-3.2. The solid obtained is filtered and washed with water (350 ml×2). The damp product is dried at 50° C. at reduced pressure for 14-16 hours, providing 337 g (yield 98%) of crude dibenzylrhein.

Example 3 Purification of 1,8-dibenzyloxyanthraquinone-3-carboxylic acid (dibenzylrhein)337 g (0.72 moles) of crude 1,8-dibenzyloxyanthraquinone-3-carboxylic acid are dissolved in a solution of 134 ml of triethylamine in 900 ml of dimethylformamide DMF and 1800 ml of ethyl acetate, heating to 60° C. for 20-30 min. Any undissolved elements are removed by hot filtering and 2700 ml of water are added. The organic phase is separated and the aqueous phase is washed 6 times with 800 ml of ethyl acetate each time, maintaining the temperature at 60° C. The organic phase is cooled to room temperature and acidified with hydrochloric acid 33% until pH 2 is reached; the suspension thus obtained is cooled to 0-5° C. for approximately 1 hour. The product is filtered, washing it thoroughly with water (1200 ml) and then with 200 ml of acetonitrile. After drying at 50° C. at reduced pressure for 14-16 hours, 256 g of dibenzylrhein are obtained with a yield of 76%.

melting point: 250-251° C.

IR cm⁻¹: 1666, 1621, 1587, 1524

Example 4 Synthesis of 1,8-diacetoxy-3-carboxyanthraquinone (diacerein)45 g (0.28 moles) of anhydrous iron trichloride are added in portions to a suspension of 255 g (0.55 moles) of 1,8-dibenzyloxyanthraquinone-3-carboxylic acid in 1300 ml of acetic anhydride. The reaction mixture is heated to 65° C. for one hour and thirty minutes. It is gradually cooled to 2-4° C. and maintained at that temperature for 1 hour. The solid obtained is filtered and washed with 150 ml of acetic anhydride and then with 400 ml of ethyl acetate. The damp product is dried at 50° C. at reduced pressure for 14-16 hours, providing 186 g of crude diacerein (yield 92%). The crude diacerein is purified according to the known techniques.

¹H NMR (d6-DMSO) δ: 2.4 (6H, s); 7.6 (1H, dd); 7.9 (1H, t); 8.0 (1H, d); 8.1 (1H, dd); 8.5 (1H, d).

IR cm⁻¹: 1763, 1729, 1655, 1619, 1591, 1183.

Chromium: not detectable (<1 ppm)

Genotoxic impurities (aloe emodin and acetyl derivatives)≦2 ppm.

/////////Diacerein, US 8324411, PATENT

US 8362006, Intervet International B.V., Boxmeer, The Netherlands, Zilpaterol, PATENT

PATENTS Comments Off

Sep 022016

Image result for Zilpaterol,

US 8362006

http://www.google.co.in/patents/US8362006

Inventors	Oliver Krebs, Stephane Dubuis
Original Assignee	Intervet International B.V.

Intervet International B.V., Boxmeer, The Netherlands

Image result for Intervet International B.V.,

Process for Making Zilpaterol and Salts Thereof

Zilpaterol is a known adrenergic β-2 agonist having the following structure:

The IUPAC name for zilpaterol is 4,5,6,7-tetrahydro-7-hydroxy-6-(isopropylamino)imidazo[4,5,1-jk]-[1]benzazepin-2(1H)-one. The Chemical Abstracts name for zilpaterol is 4,5,6,7-tetrahydro-7-hydroxy-6-[(1-methyl-ethyl) amino]-imidazo [4,5,1-jk][1]benzazepin-2(1H)-one.It is well known that zilpaterol, various zilpaterol derivatives, and various pharmaceutically acceptable acid addition salts of zilpaterol and its derivatives may, for example, be used to increase the rate of weight gain, improve feed efficiency (i.e., decrease the amount of feed per amount of weight gain), and/or increase carcass leanness (i.e., increase protein content in carcass soft tissue) in livestock, poultry, and/or fish. In U.S. Pat. No. 4,900,735, for example, Grandadam describes zootechnical compositions of racemic trans zilpaterol and salts thereof that may be used to increase the weight and meat quality of warm-blooded animals, including cattle, pigs, and poultry. And U.S. Patent Appl. Publ. US2005/0284380 describes use of an ionophore/macrolide/zilpaterol dosing regimen to increase beef production, reduce feed intake while maintaining beef production, and reduce incidences of liver abscess in cattle.

Methods for making zilpaterol are known in the art. For example, in U.S. Pat. No. 4,585,770, Fréchet et al. describe compounds encompassed by a genus characterized as 6-amino-7-hydroxy-4,5,6,7-tetrahydro-imidazo[4,5,1-jk][1]-benzazepin-2[1H]-one derivatives and pharmaceutically acceptable acid addition salts thereof. The derivatives correspond in structure to the following formula:

Here, R can be various substituents, and the wavy lines indicate that the bonds to the 6-amino and 7-OH groups have the trans configuration. This genus encompasses racemic trans zilpaterol when R is isopropyl.The methods reported in U.S. Pat. No. 4,585,770 use 4,5-dihydro-imidazo[4,5,1-jk][1]benzazepin-2,6,7[1H]-trione-6-oxime as an intermediate. This compound corresponds in structure to the following formula:

As indicated in U.S. Pat. No. 4,585,770, 4,5-dihydro-imidazo[4,5,1-jk][1]benzazepin-2,6,7[1H]-trione-6-oxime may be formed from starting materials that have been long known in the art. U.S. Pat. No. 4,585,770 illustrates the use of two such starting materials. In both examples, the starting materials are used to form 5,6-dihydro-imidazo[4,5,1-jk][1]benzazepin-2,7-[1H,4H]-dione, which, in turn, may be used to make 4,5-dihydro-imidazo[4,5,1-jk][1]benzazepin-2,6,7[1H]-trione-6-oxime.In one of the examples in U.S. Pat. No. 4,585,770, the starting material is 1,3-dihydro-1-(1-methylethenyl)-2H-benzimidazol-2-one, which is described in J. Chem. Soc. Perkins, p. 261 (1982):

U.S. Pat. No. 4,585,770 indicates that 1,3-dihydro-1-(1-methylethenyl)-2H-benzimidazol-2-one may be reacted with an alkyl 4-halobutyrate (i.e., R^A—(CH₂)₃—COOR^B(wherein R^Ais Cl, Br, or I; and R^Bis C₁-C₄-alkyl), such as methyl or ethyl 4-bromobutyrate) and a base (e.g., an alkali metal) to form a butanoate, which, in turn may be hydrolyzed with an acid (e.g., H₂SO₄) in an alkanol (e.g., methanol or ethanol) to remove the methylethenyl substituent. The hydrolysis product then may be subjected to saponification by reacting it with a base (e.g., NaOH or KOH) in an alkanol to form a carboxylic acid. Subsequently, the carboxylic-acid-terminated side chain may be cyclized to form 5,6-dihydro-imidazo[4,5,1-jk][1]benzazepin-2,7-[1H,4H]-dione by reacting the carboxylic acid with thionyl chloride to obtain a chloride, and then treating the chloride with a Lewis acid (e.g., aluminum chloride) in an organic solvent (e.g., methylene chloride or dichloroethane):

See U.S. Pat. No. 4,585,770, col. 4, line 3 to col. 5, line 14; and Example 14, col. 12, lines 1-68.In another example in U.S. Pat. No. 4,585,770, the starting material is 1,3-dihydro-1-benzyl-2H-benzimidazol-2-one, which is described in Helv., Vol 44, p. 1278 (1961):

U.S. Pat. No. 4,585,770 indicates that the 1,3-dihydro-1-benzyl-2H-benzimidazol-2-one may be reacted with ethyl 4-bromobutyrate and sodium hydride to form 1,3-dihydro-2-oxo-3-benzyl-1H-benzimidazol-1-butanoate, which, in turn may be subjected to saponification by reacting it with methanolic NaOH to form 1,3-dihydro-2-oxo-3-benzyl-1H-benzimidazol-1-butanoic acid. The butanoic acid side chain may then be cyclized by reacting the 1,3-dihydro-2-oxo-3-benzyl-1H-benzimidazol-1-butanoic acid with thionyl chloride to obtain a chloride, and then treating the chloride with aluminum chloride in dichloroethane. The cyclized product, in turn, may be hydrolyzed using o-phosphoric acid in phenol to form 5,6-dihydro-imidazo[4,5,1-jk][1]benzazepin-2,7-[1H,4H]-dione. See U.S. Pat. No. 4,585,770, Example 1, Steps A-D, col. 6, line 10 to col. 7, line 35.Using the methods reported in U.S. Pat. No. 4,585,770, 5,6-dihydro-imidazo[4,5,1-jk][1]benzazepin-2,7-[1H,4H]-dione may be reacted with an alkyl nitrite (e.g., tert-butyl nitrite or isoamyl nitrite), in the presence of a base or acid (e.g., HCl), to form 4,5-dihydro-imidazo[4,5,1-jk][1]benzazepin-2,6,7[1H]-trione-6-oxime. The 4,5-dihydro-imidazo[4,5,1-jk][1]benzazepin-2,6,7[1H]-trione-6-oxime, in turn, is reduced via catalytic hydrogenation (with, for example, hydrogen in the presence of palladium on carbon) or sodium borohydride to form racemic trans 6-amino-7-hydroxy-4,5,6,7-tetrahydro-imidazo[4,5,1-jk][1]-benzazepin-2[1H]-one:

In the illustrative example in U.S. Pat. No. 4,585,770, the 4,5-dihydro-imidazo[4,5,1-jk][1]benzazepin-2,6,7[1H]-trione-6-oxime is converted into racemic trans 6-amino-7-hydroxy-4,5,6,7-tetrahydro-imidazo[4,5,1-jk][1]-benzazepin-2[1H]-one in two steps: the 4,5-dihydro-imidazo[4,5,1-jk][1]benzazepin-2,6,7[1H]-trione-6-oxime is first reacted with H₂in the presence of Pd-on-carbon, and, then, after filtration, the hydrogenation product is reacted with sodium borohydride. See U.S. Pat. No. 4,585,770, col. 2, line 15 to col. 4, line 2; and Example 1, Steps E & F, col. 7, line 38 to col. 8, line 3.U.S. Pat. No. 4,585,770 reports that the trans stereoisomers of 6-amino-7-hydroxy-4,5,6,7-tetrahydro-imidazo[4,5,1-jk][1]-benzazepin-2[1H]-one may be alkylated with acetone in the presence of a reducing agent (e.g., an alkali metal borohydride or cyanoborohydride, such as sodium cyanoborohydride) to form racemic trans zilpaterol:

See U.S. Pat. No. 4,585,770, col. 2, line 46 to col. 4, line 2; and Example 13, col. 11, lines 41-68.In view of the importance of zilpaterol and its salts in animal production, there continues to be a need for cost-effective, high-yield processes for making zilpaterol and its salts. The following disclosure addresses this need.

OVERVIEW

Zilpaterol 121 is used to increase the rate of weight gain in livestock, poultry, and fish. The drug is available as Zilmax and is marketed as beef improvement technology. There are a number of methods for preparing 121, and the patent specifically focuses on the method reported in a 1986 patent, U.S. 4,585,770, that is compared with the process described in the current patent.

The new process is outlined in Schemes 37 and 38, and the examples in the patent describe the manufacture of 121 on a commercial scale starting from 525 kg of 116a.

Unfortunately, the yield of the reaction products is not reported in any of the steps. The process starts with the chlorination of the acid 116a to give 116b that is carried out using (COCl)₂, although COCl₂ or triphosgene are also claimed to be suitable. The product is isolated as a solution in DCM after a workup involving transferring between three vessels, adding H₂O, and distilling off the solvent.

In the next stage an intramolecular Friedel–Crafts alkylation of 116b in the presence of AlCl₃ followed by acid hydrolysis forms 117. This is isolated as a wet solid and then is converted to the oxime 118a in DMF by treatment with NaNO₂ followed by addition of HCl.

Scheme 37. ^a

^aReagents and conditions: (a) (i) DMF, DCM, 10 °C; (ii) (COCl)₂, 10 °C, 3 h; (iii) 20 °C, 3 h. (b) (i) AlCl₃, DCM, 60 °C, 3 to 7 h; (ii) cool to <20 °C, add H₂O/33% aq HCl; (iii) cool, evacuate, distill DCM; (iv) centrifuge, wash in PrⁱOH. (c) (i) NaNO₂, DMF, 45 °C; (ii) 33% HCl, 48 °C, 1 h; (iii) 60 °C, 0.5 h; (iv) cool to 45 °C, 2 h; (v) add DMF and H₂O; (vi) cool, to 0 °C, 11 h; (vii) centrifuge at 0 °C; (viii) H₂O wash, wash in Me₂CO, dry.

Compound 118a is isolated as a dry solid that is converted to the potassium salt by treatment with 45% aq KOH as shown in Scheme 38. The salt is isolated as a solution that is treated with active C and then hydrogenated in the presence of Pd/C catalyst to form the amino alcohol salt 119.

This reaction appears to be stereoselective, although no reference to this is made in the patent. The salt, 119, is recovered as an aqueous solution that is used in the next step where it is reacted with Me₂CO in the presence of HOAc at a pH of 7–8. This produces the isopropylidene amino compound, 120, that is not isolated but undergoes hydrogenation in the presence of Pt/C catalyst to give the HOAc salt, 121·HOAc.

The free base form, 121, is obtained by treating the salt with NaOH in EtOH, and from the free base, a HCl salt can be prepared.

Scheme 38. ^a

^aReagents and conditions: (a) (i) H₂O, 45 °C; (ii) 45% aq KOH, 40 °C; (iii) active C, 0.5 h; (iv) filter. (b) (i) Pd/C, H₂O, 15 °C; (ii) H₂, 10 bar, 40 °C, 6 h; (iii) filter, H₂O wash. (c) HOAc to pH 8, 30 °C. (d) (i) cool 15 °C, Pt/C, H₂O; (ii) H₂ 9 bar, 70 °C, 2 h; (iii) add HOAc, 30 °C, pH 6.8; (iv) filter at 30 °C; (v) wash in aq HOAc.

The patent discusses aspects of the process is some detail such as the quantities of washing solvents used.

Advantages

The process provides an effective route to the desired compound and is clearly suitable for large-scale manufacture.

The following Scheme I generically illustrates a scenario wherein all the above reactions are used:

The following Scheme II generically illustrates the above scenario wherein the chlorinating agent comprises oxalyl chloride; the Lewis acid comprises AlCl₃; the hydrolysis acid following the Friedel-Crafts reaction comprises HCl; the inorganic nitrite comprises NaNO₂; the acid used in the oximation comprises HCl; water is added to the oximation product mixture to foster isolation of the oxime product; the base used to form the oxime salt comprises KOH; the catalyst for the first hydrogenation comprises palladium on carbon; the acid used in the formation of the isopropylideneamino compound comprises acetic acid; the catalyst for the second hydrogenation comprises platinum on carbon; and the base and alcohol used to form the zilpaterol free base comprise NaOH and ethanol, respectively:

Example 1 Preparation of 8,9-dihydro-2H,7H-2,9a-diazabenzo[cd]azulene-1,6-dione Part A. Preparation of chloro 2,3-dihydro-2-oxo-1H-benzimidazol-1-butanoate

4-(2-Oxo-2,3-dihydrobenzimidazol-1-yl)butyric acid (50 g; 0.227 mol), N,N-dimethylformamide (1.84 g; 0.025 mol; 0.11 eq), and dichloromethane (480 g; 5,652 mol; 24.89 eq) were charged to a stirred-tank reactor. Oxalyl chloride (31.12 g; 0.245 mol; 1.08 eq) was then dosed at 10-20° C. over a 1-hour period while stirring. The resulting mixture was then stirred at 10-20° C. for an additional hour. All the above steps were conducted under a N₂atmosphere.Part B. Preparation of 8,9-dihydro-2H,7H-2,9a-diazabenzo[cd]azulene-1,6-dione.

The reaction product mixture from Part A was added to a slurry of aluminum chloride (100 g; 0.75 mol, 3.3 eq) in dichloromethane (320 g; 3.768 mol; 16.59 eq) over 2-5 hours at 60° C. and a pressure of 2.7 bar (absolute) in a stirred-tank reactor that allowed HCl gas to escape through an overpressure vent. The resulting slurry was stirred for an additional hour at that temperature, and then cooled to 12° C. In a separate stirred-tank reactor, water (800 g; 44.407 mol; 195.59 eq.) and aqueous 32.5% HCl (118 g; 1.052 mol HCl; 4.63 eq. HCl) were mixed. This mixture was cooled to 0° C., and the gas in the headspace was evacuated to 300 mbar (absolute). The slurry from the first reactor was then added portion-wise to the second reactor, whereby the temperature increased to 10-15° C. under distillation of dichloromethane. The first reactor was rinsed with additional dichloromethane (25 g; 0.294 mol; 1.3 eq), which was then added to the second reactor. Distillation of the dichloromethane was then completed at 300 mbar to atmospheric pressure (absolute) and 12-40° C. The resulting suspension was cooled to 0° C. The solid was filtered off, and washed 4 times with water (291.25 g each time; 64.668 mol total; 284.83 eq. total) and once with isopropanol (80 g; 1.331 mol; 1.331 eq) at 0° C. All the above steps were conducted under a N₂atmosphere.Example 2 Preparation of 4,5-dihydro-imidazo[4,5,1-jk][1]benzazepin-2,6,7[1H]-trione-6-oxime.

8,9-Dihydro-2H,7H-2,9a-diazabenzo[cd]azulene-1,6-dione (50 g; 92.4% purity; 0.228 mol) prepared in accordance with the procedure in Example 1 was dried and mixed with isopropanol (7.23 g; 0.12 mol; 0.53 eq) and water (3.01 g; 0.167 mol; 0.73 eq) (in alternative experiments and in production, 8,9-dihydro-2H,7H-2,9a-diazabenzo[cd]azulene-1,6-dione prepared in accordance with the procedure in Example 1 was instead used as centrifuge-wet material without the addition of water and isopropanol). The resulting wet 8,9-dihydro-2H-7H-2,9a-diazabenzo[cd]azulene-1,6-dione was combined with sodium nitrite (19.05 g at 99.3% purity; 0.274 mol; 1.2 eq) and N,N-dimethylformamide (800 g; 10.945 mol; 47.9 eq) in a stirred-tank reactor. The mixture was heated to 50° C., and then 32% HCl (41.65 g; 0.366 mol HCl; 1.6 eq HCl) was added over a 30 minute period. Toward the end of the HCl addition (i.e., after greater than 1 eq HCl had been added), the temperature quickly increased to 60-70° C. After all the HCl was added, the mixture was stirred at 60° C. for an additional 30 minutes. The mixture then was cooled to 35° C. over a 2- hour period. Next, water (224.71 g; 12.473 mol; 54.6 eq) was added over a 2-hour period. The resulting mixture was then cooled to 0° C. over a 2-hour period, and maintained at that temperature for 2 hours. Afterward, the solid 4,5-dihydro-imidazo[4,5,1-jk][1]benzazepin-2,6,7[1H]-trione-6-oxime product was removed by filtration and washed 4 times with water (70.1 ml each time; 15.566 mol total; 68.13 eq total) and once with acetone (115.9 g; 99.9% purity; 1.994 mol; 8.73 eq). All the above steps were conducted under a N₂atmosphere.Example 3 Scale-up Preparation of 8,9-dihydro-2H,7H-2,9a-diazabenzo[cd]azulene-1,6-dione Part A. Preparation of chloro 2,3-dihydro-2-oxo-1H-benzimidazol-1-butanoate

Dichloromethane (3772 L) and then 4-(2-oxo-2,3-dihydrobenzimidazol-1-yl)butyric acid (525 kg; 2.4 kmol) were charged to a stirred-tank reactor, followed by N,N-dimethylformamide (21 L). The resulting mixture was cooled to 10° C. Afterward, oxalyl chloride (326.8 kg)) was dosed at 10-15° C. over 2-3 hours while stirring. The resulting mixture was then stirred at 15-20° C. for an additional 1-3 hours. All the above steps were conducted under a N₂atmosphere. Conversion was checked by in-process control (“IPC”).Part B. Preparation of 8,9-dihydro-2H,7H-2,9a-diazabenzo[cd]azulene-1,6-dione.

Aluminum chloride (1050 kg) and dichloromethane (2403 L) at 10-20° C. were charged to a stirred-tank reactor, followed by additional dichloromethane (112 L) at 10-20° C. to rinse the reactor. The reactor was then pressurized with N₂to 2.7 bar (absolute), and heated to 58-60° C. Next, the product mixture from Part A was added over 2−5 hours. The resulting slurry was stirred for an additional 1-2 hours, and then cooled to 10-20° C. Afterward, the pressure was released. In a second stirred-tank reactor at 5° C., water (3675 L) was charged, followed by aqueous 33% HCl (452 L). This mixture was cooled to 0° C., and the gas in the headspace was evacuated to 270-470 mbar (absolute). About half the content from the first reactor was added to the second reactor at from 5-20° C. The mixture was maintained at 10-30° C. for an additional 30-90 minutes. In parallel to and following the transfer, distillation of dichloromethane occurred. The line between the two reactors was rinsed with dichloromethane (150 ml). The resulting rinse and the contents in the second reactor were transferred to a thud stirred-tank reactor. The transfer line between the second and third reactors was rinsed with water (200 L). This rinse also was charged to the third reactor. Water (3675 L) at 5° C. and 33% HCl (452 L) were then added to the second reactor. The resulting mixture was cooled to 0° C., and the pressure in the headspace was set to between 270-470 mbar (absolute). The second half of the content from the first reactor was then added to the second reactor at 5-20° C. This mixture was maintained at 10-30° C. for an additional 30-90 minutes. In parallel to and following the transfer, distillation of dichloromethane occurred. The line between the first and second reactors was rinsed with dichloromethane (150 ml). The resulting rinse and the contents in the second reactor were transferred to the third reactor. The transfer line between the second and third reactors was then rinsed with water (200 L). This rinse was charged to the third reactor. In the third reactor, the dichloromethane was further distilled at 30-40° C. under atmospheric pressure. When the distillation was complete, the suspension was cooled to 0−5° C., and then centrifuged in two parts. Each of the resulting cakes was washed with four times water (390 L for each wash) and once with isopropanol (508 L) at 0−5° C. All the above steps were conducted under a N₂atmosphere.Example 4 Scale-up of Preparation of 4,5-dihydro-imidazo[4,5,1-jk][1]benzazepin-2,6,7[1H]-trione-6-oxime.

At 20° C., N,N-dimethylformamide (7068 L) was charged to a stirred-tank reactor, followed by 8,9-dihydro-2H,7H-2,9a-diazabenzo[cd]azulene-1,6-dione (450 kg total wet material, approximately 405 kg pure) prepared in accordance with the procedure in Example 3. The addition funnel was rinsed with N,N-dimethylformamide (105 L), and the rinse was charged to the reactor. The resulting mixture was heated at 45° C. until all the 8,9-dihydro-2H,7H-2,9a-diazabenzo[cd]azulene-1,6-dione was in solution. IPC was used to check the amount of pure 8,9-dihydro-2H,7H-2,9a-diazabenzo[cd]azulene-1,6-dione in the mixture, and, from that measurement (together with the mass of wet 8,9-dihydro-2H,7H-2,9a-diazabenzo[cd]azulene-1,6-dione and N,N-dimethylformamide), the exact amount of 8,9-dihydro-2H,7H-2,9a-diazabenzo[cd]azulene-1,6-dione was calculated, which, in turn, was used to calculate the amounts of N,N-dimethylformamide (17.3 kg/kg), sodium nitrite (0.412 kg/kg) and HCl 33% (0.873 kg/kg). For the duration of the IPC, the mixture was cooled to 20° C. Next, sodium nitrite (167 kg, based on 405 kg 8,9-dihydro-2H,7H-2,9a-diazabenzo[cd]azulene-1,6-dione) was added. The addition funnel was rinsed with N,N-dimethylformamide (105 L), and the rinse was charged to the reactor. The temperature was then increased to 45° C. Subsequently, additional N,N-dimethylformamide was charged in the amount calculated earlier (97 L, based on having a total of 7375 L DMF for 405 kg of 8,9-dihydro-2H,7H-2,9a-diazabenzo[cd]azulene-1,6-dione). Next, the resulting mixture was warmed to 48° C., and then 33% HCl (353 kg, based on the batch size) was added over 1 hour, causing the temperature to increase to 60-65° C. by the end of the addition. The mixture was then stirred at 60° C. for another 30 minutes. Next, the mixture was cooled to 45° C. over 1-2 hours. The resulting mixture was transferred into a second reactor. The first reactor was subsequently rinsed with N,N-dimethylformamide (105 L), and the rinse was charged to the second reactor. Water (2000 L) was then added over a 2-hour period at 38° C. The resulting mixture was cooled to 0° C. over 2-3 hours, and then stirred at that temperature for another 2-8 hours. Afterward, the mixture was centrifuged at 0° C., and the resulting cake was washed with three times with water (810 L each time), washed with acetone (1010 L), and dried at 65° C. under vacuum. All the above steps, except for the IPC, were conducted under a N₂atmosphere.Example 5 Preparation of Zilpaterol Part A. Formation of Aminoalcohol Potassium Salt from Ketooxime

A stirred-tank reactor was purged 3 times with N₂between high pressure (3 bar, absolute) and low pressure (1 bar, absolute) for 10 minutes each. Then a pressure of 0.9 bar (absolute) was established. Water (790 kg) was then charged to the reactor, followed by 4,5-dihydro-imidazo[4,5,1-jk][1]benzazepin-2,6,7[1H]-trione-6-oxime (255 kg) prepared in accordance with Example 4. The reactor contents were then heated to 40° C. Next, 45% KOH (214 kg) was continuously charged to the reactor, causing 4,5-dihydro-imidazo[4,5,1-jk][1]benzazepin-2,6,7[1H]-trione-6-oxime to form the corresponding potassium salt, which, in turn, dissolved (this could be visually verified). The reactor was then charged with active charcoal (13 kg). The resulting mixture was then stirred for 30 minutes at 40° C. The resulting mixture was filtered through a filter loop for one hour to remove the active charcoal. The mixture was then cooled to 15° C. A 5% palladium-on-carbon catalyst (25.5 kg, Johnson-Matthey) was then charged to the reactor. The reactor was then rinsed with water (50 kg). The resulting mixture in the reactor was stirred for 2-6 hours at 40° C. and a H₂pressure of 5-10 bar (absolute). Afterward, the reactor was vented over 30 minutes, and the reaction was analyzed using HPLC. The contents were then filtered in a filter loop for 90 minutes. The filter cake was washed with water (50 L), and removed to recover palladium. The filtered solution was analyzed via HPLC to confirm complete conversion, and then used in the next step.Part B. Formation of zilpaterol-HOAc.

The solution from Part A was cooled to 30° C. Acetone (625 L) was then charged to the reactor. Acetic acid was added to adjust the pH to 7.5 (a pH of from about 7 to about 8 is preferred). The resulting mixture was then cooled to 15° C. Next, a 5% platinum-on-carbon catalyst (21.3 kg, Degussa) was charged to the reactor, followed by water (50 kg) to rinse the reactor. The head space was purged 3 times with H₂between a high pressure of 5 bar (absolute) and a low pressure of 1 bar (absolute) for 15 minutes each. Then a hydrogen pressure of 9.0 bar (absolute, for hydrogenation) was established. The mixture was heated to 70° C. over 1 hour while being stirred, and then maintained at that temperature for an additional hour while being stirred. The reactor was then vented, and the headspace was purged with N₂. The reaction was analyzed using HPLC. Acetic acid (8 kg) was then charged to the reactor, and the resulting mixture was cooled to 30° C. More acetic acid was added to adjust the pH to 6.8. The mixture was then transferred through a filter loop for 1 hour while being maintained at 30° C. The resulting cake was washed with 7% aqueous acetic acid (75 L). The filtered solution was transferred to another stirred-tank reactor to be used in the next step.Part C. Formation of Zilpaterol Free Base

The stirred-tank reactor containing the product from Part B was purged 3 times with N₂between high pressure (2 bar, absolute) and low pressure (1 bar, absolute) for 10 minutes each. Then a pressure of 0.9 bar (absolute) was established. Next, the mixture was concentrated by distillation to 30-70%. The concentrated mixture was cooled to 65° C. Ethanol (331 L) was charged to the reactor, and the resulting mixture was cooled to 50° C. The pH was adjusted to 10 using 25% NaOH. This caused zilpaterol free base to precipitate. The temperature was decreased to 0° C. to facilitate the precipitation, and maintained at that temperature for an additional hour. The solids were filtered off, and washed with water (700 L).Example 6 Synthesis of an HCl Salt of the ZilpaterolThe free base of zilpaterol is dissolved in ethanol. Subsequently, ethyl acetate saturated with HCl is added. The resulting mixture is vacuum-filtered to obtain a crude product containing the HCl salt of the zilpaterol. The crude product is dissolved in hot methanol. Ethyl acetate is then added, and the mixture is filtered to obtain the final HCl salt product.

Example 7 First Illustration of a Contemplated Suitable Dosage FormA tablet is prepared containing 2.5 or 5 mg of the HCl salt of Example 6, and sufficient excipient of lactose, wheat starch, treated starch, rice starch, talc, and magnesium stearate for a final weight of 100 mg.

Example 8 Second Illustration of a Contemplated Suitable Dosage FormGranules are prepared containing 12.5 or 25 of the HCl salt of Example 6 in each daily dose of granules.

Example 9 Third Illustration of a Contemplated Suitable Dosage FormThe HCl salt of Example 6 is crystallized using the methodology discussed U.S. Pat. No. 5,731,028 for making crystalline racemic trans zilpaterol. Less than 5% of the crystals have a size of less than 15 μm, and at least 95% of the crystals have a size of less than 250 μm. A premix of the crystalline HCl salt secured to a 300-800 μm corn cob support is then obtained using the methodology discussed in European Patent 0197188 (incorporated by reference into this patent). The concentration of the HCl salt in the premix is 3% (by weight).

Cited Patent	Filing date	Publication date	Applicant	Title
US4585770	12 Oct 1983	29 Apr 1986	Roussel Uclaf	Novel 6-amino-7-hydroxy-4,5,6,7-tetrahydro-imidazo[4,5,1-j-k][1]-benzazepin-2-(1H)-one
US5731028	6 Jun 1996	24 Mar 1998	Roussel Uclaf	Crystallized zilpaterol hydrochloride
US20060040950	17 Dec 2003	23 Feb 2006	Janssens Frans E	Substituted 1-piperidin-4-yl-4-pyrrolidin-3-yl-piperazine derivatives and their use as neurokinin antagonists
US20080267942 *	11 Apr 2008	30 Oct 2008	Pfizer Limited	Benzazepin-2(1h)-one derivatives
US20100173892 *	31 Jan 2008	8 Jul 2010	Juan Jose Almena-Perea	Enantioselective synthesis of 6-amino-7-hydroxy-4,5,6,7-tetrahydro-imidazo[4,5,1-JK][1]-benzazepin-2[1H]-one and zilpaterol
WO2004056799A2	17 Dec 2003	8 Jul 2004	Janssen Pharmaceutica N.V.	Substituted 1-piperidin-4-yl-4-pyrrolidin-3-yl-piperazine derivatives and their use as neurokinin antagonists
WO2008119754A1	28 Mar 2008	9 Oct 2008	Intervet International B.V.	Processes for making zilpaterol and salts thereof

////////US 8362006, Intervet International B.V., Boxmeer, The Netherlands, Zilpaterol, PATENT

Gefitinib, US 8350029, CIPLA

PATENTS Comments Off

Sep 022016

US 8350029

http://www.google.co.in/patents/US8350029

Inventors	Dharmaraj Ramachandra Rao, Rajendra Narayanrao Kankan, Srinivas Laxminarayan Pathi,
Original Assignee	Cipla Limited

CIPLA Limited, Mumbai, India

Gefitinib is an anilinoquinazoline which is useful in the treatment of a certain type of lung cancer (non-small cell lung cancer or NSCLC) that has not responded to chemotherapy. The chemical name for gefitinib is 4-(3′-chloro-4′-fluoroanilino)-7-methoxy-6-(3-morpholinopropoxy)quinazoline. Its structural formula is:

The earliest known synthesis of gefitinib was first disclosed in the patent application WO 96/33980. The synthetic method employed is depicted in the following reaction scheme 1.

The process involves selective demethylation of 6,7-dimethoxy quinazoline-4-one using methanesutfonic acid and L-methionine to get its 6-hydroxyl derivative, which is protected by acetylation. The acetoxy compound is chlorinated and condensed with chloro-fluoroaniline. Hydrolysis of the acetoxy compound followed by etherification with 3-morpholinopropyl chloride gives crude gefitinib which is purified by column chromatography. The process suffers from many disadvantages as it involves several protection and deprotection steps. The selective demethylation using methionine results in isomeric impurities and has to be purified or else the impurity carries over to subsequent steps in the preparation of gefitinib making it more difficult to isolate a pure product. The process also leads to formation of an N-alkylated impurity at the final stage which must be separated by column chromatography to obtain gefitinib.

Several other approaches are also described in the literature to make gefitinib.

WO 2004/024703 discloses a process for the preparation of gefitinib starting from 3-hydroxy-4-methoxy benzonitrile which involves condensation of 3-hydroxy-4-methoxy benzonitrile with morpholino propyl chloride, nitration, reduction with sodium dithionite to amino compound, hydrolysis of nitrile to amide, cyclisation in the presence of formamide to obtain quinazoline, chlorination with phosphorous oxychloride and finally condensation with chloro-fluoro aniline to obtain gefitinib. The process involves multiple steps and hence is time consuming.

WO 2005/023783 discloses a process for the manufacture of gefitinib starting from 2-amino-4-methoxy-5-(3-morpholinopropoxy)benzonitrile. The process involves a rearrangement reaction of 3-(3-chloro-4-fluorophenyl)-7-methoxy-6-(3-morpholinopropoxy)3,4-dihydroqunazoline-4-imine. The process is not feasible industrially, as the basic raw material is not readily available on a commercial scale and involves the use of excess 3-chloro-4-fluoroaniline which is expensive. A further draw back of the process is in the isomerization of the 4-imine compound which requires anhydrous conditions at high temperature for a longer duration of 96 hours. All the problems associated with this prior art process are overcome by the novel process of the present invention.

WO2005/070909 discloses a process for the preparation of gefitinib starting from isovanillin as depicted in scheme 2

The WO’ 909 process has disadvantages as it forms cis-trans geometrical isomers of the oxime, which have different reactivities. Furthermore, the process uses a large excess of acetic anhydride to convert the oxime to the nitrile at higher temperature.

The patent applications 901/CHE/2006 and 903/CHE/2006 disclose another route for preparing gefitinib starting from isovanillin. The process involves formation of a formamido compound [N′-[2-cyano-4-{3-(4-morpholinyl)propoxy}phenyl]-N,N-dimethyl formamide], which is unstable and may result in undesired impurities in the final condensation with 3-chloro-4-fluoro aniline, thereby making the process less feasible on an industrial scale.

The processes disclosed in the prior art are cumbersome. Therefore, there exists a need for a more economical and efficient method of making gefitinib which is suitable for industrial scale-up.

The process of the present invention avoids use of reagents such as sodium dithionite, acetic anhydride and allows substantial reduction in the number of problems associated with these reagents.

Process for Preparation of Gefitinib

Gefitinib, 66, is used in the treatment of certain types of lung cancer, and a number of methods are reported for its synthesis. These are described as cumbersome and can require excessive amounts of reagents or involve difficult purification methods. Some processes use reagents such as sodium dithionite or Ac₂O, and these are said to create problems. This patent discloses two routes for the synthesis of 66 that are claimed to avoid such problems. The first route, shown in Scheme 22, is the subject of the claims of the patent and starts with the nitration of isovanillin 57ain HOAc to give 57b that is recovered in 65% yield. Treatment of 57b with 58 produces 59a that is isolated in 92% yield, and this is then oxidised with H₂O₂ to form the acid 59b that is isolated in 86% yield. Reduction of the nitro group is then carried out to give 60, and there are three methods described for this reaction. The first is catalytic hydrogenation with Pd/C that gives a 90% yield of60. The reaction pressure is reported as being 5–6 kg, a common term in India used as short-hand for the pressure unit of kg/m². Reduction using H₂NNH₂ in the presence of FeCl₃, Al₂O₃, and charcoal gives a 83.6% yield of 60. In a hydrogen-transfer reaction with HCO₂NH₄ and Pd/C compound, 60 is recovered in 84.5% yield. The cyclisation of 60 to form 61 is carried out in a Niementowski reaction using HCO₂NH₄ and HCO₂NH₂, and the product is recovered in 90% yield. Reaction of 61 with SOCl₂ produces 62, and this is isolated in 95% yield. Only the main reagents are shown in the scheme, and workup details are omitted.

Scheme 22. ^a

^aReagents and conditions: (a) (i) HNO₃, HOAc, −5 °C; (ii) 30 °C, 12 h. (b) K₂CO₃, MeCN, reflux, 4 h. (c) (i) 30% NaOH/MeOH, 45 °C; (ii) add 35% H₂O₂ over 4 h, 45 °C, pH 11. (d) Pd/C, H₂, EtOAc, 40 °C, 4 h. (e) HCO₂NH₄, HCO₂NH₂, 180 °C, 4 h. (f) SOCl₂, DMF, reflux, 8 h.

In the next stage of the synthesis, shown in Scheme 23, compound 62 is reacted with morpholine63 to give 64 in 85% isolated yield. In the final step 64 is reacted with 65 to produce 66 that is recovered in 70% yield (purity not reported).

Scheme 23. ^a

^aReagents and conditions: (a) (i) 75 °C, 8 h; (ii) cool to rt, add H₂O; (iii) separate extract in DCM, H₂O wash, dry, evaporate. (b) MeOH, 30 °C, 0.25 h; (ii) add 65, reflux 6 h; (iii) add HCl at 20 °C; (iii) <10 °C, 0.5 h; (iv) filter, MeOH wash; (v) dissolve in PhMe/MeOH, concentrate; (vi) cool <10 °C, filter, PhMe wash, dry.

The patent also describes an alternative route to 66 that is outlined in Schemes 24 and 25although it is not covered by the patent claims. The route starts with the oxidation of 57a using H₂O₂ to give the acid 67a that is esterified to form 67b that is isolated in 83% yield. Nitration of67b with HNO₃ in HOAc produces 68a that is isolated in 74% yield and then reduced to 68b over Pd/C. The amine 68b is recovered in 93% yield and then reacted with 69 to give the quinazoline70a that is recovered in 92% yield and then acetylated to form 70b. There is no example describing this acetylation nor are there any for the remaining steps of this route shown in Scheme25, and the reactions are just generally referred to in the text.

Scheme 24. ^a

^aReagents and conditions: (a) (i) 30% NaOH/MeOH, 45 °C; (ii) add 35% H₂O₂ over 3 h, 45 °C, pH 11. (b) 10% HCl/MeOH, reflux, 6 h. (c) 70% HNO₃, HOAc, −5 °C, 18 h. (d) Pd/C, H₂, EtOAc, 40 °C, 4 h. (e) MeOH, reflux, 10 h. (f) No details.

Scheme 25. ^a

^aReactions: (a) Chlorination. (b) Condensation. (c) Hydrolysis. (d) Coupling.

The examples report experiments carried out on a reasonable scale with some producing up to 200 g of products. Unfortunately, there are no details of the purity of any of the intermediates, and although the patent states that the desired final product 66 is purified by acid/base treatment or crystallisation, there are no details provided.

Advantages

The process does avoid the use of some difficult reagents used elsewhere, but whether the process gives a higher-purity product than alternatives is not clear.

scheme 3.

scheme 4.

EXAMPLE 1 Preparation of 4-(3′-chloro-4′-fluoroanilino)-7-methoxy-6-(3-morpholinopropoxy)-quinazoline (gefitinib) (Formula I)Methanol (1200 ml) and 6-(3-morpholino propoxy)-7-methoxy-4-chloro quinazoline (200 gm) were stirred for 15 minutes at 25-30° C., then a solution of 4-fluoro-3-chloroaniline in methanol (213 gm in 400 ml) was charged and refluxed for 6 hours. The reaction mass was cooled to 15-20° C., hydrochloric acid (40 ml) was added drop wise, and stirred at 5-10° C. for 30 minutes. The solid obtained was filtered and washed with chilled methanol (150 ml). The solid was dissolved in a mixture of toluene (30 volume) and methanol (5 volume), the reaction mass was concentrated to half the volume and cooled to 5-10° C. The solid obtained was filtered, washed with toluene (200 ml) and dried at 45-50° C. to yield the title compound (183 gm, 70% yield).

EXAMPLE 2 Preparation of 6-(3-morpholino propoxy)-7-methoxy-4-chloroquinazoline (Formula VII)DMF (3 lt), 6-(3-chloropropoxy)-7-methoxy-4-chloro quinazoline (200 gm) and morpholine (210 gm), were heated to 70-75° C. for 6-8 hours. The reaction mass was cooled to room temperature, and methylene chloride (2.5 lt) and water (2.5 lt) were charged. The layers separated and the aqueous layer extracted with methylene chloride twice (500 ml). The combined methylene chloride layer was washed with water, dried over sodium sulphate (10 gm) and concentrated completely at 35-40° C. to yield the title compound (200 gm, 85% yield).

EXAMPLE 3 Preparation of 6-(3-chloropropoxy)-7-methoxy-4-chloroquinazoline (Formula VI)6-(3-chloropropoxy)-7-methoxyquinazoline-4-one (400 gm), thionyl chloride (3.2 lt) and DMF (100 ml) were refluxed for 7-8 hours. Thionyl chloride was distilled off completely under reduced pressure below 45° C. Methylene chloride (2.5 lt) and water (1.5 lt) were charged, stirred for 30 minutes at room temperature and the layers separated. The aqueous layer was extracted twice with methylene chloride (500 ml), the combined methylene chloride layer was washed with 1% sodium bicarbonate solution (1 lt), dried over sodium sulphate (20 gm) and concentrated under reduced pressure at 35-40° C. The residue was stirred with isopropyl alcohol (400 ml) at 40-45° C. for 1 hour, cooled to 0-5° C., the solids filtered, washed with chilled isopropyl alcohol (200 ml) and dried under vacuum at 45° C. to yield the title compound (406 gm, 95% yield).

EXAMPLE 4 Preparation of 6-(3-chloropropoxy)-7-methoxyquinazoline-4-one (Formula V)2-amino-4-methoxy-5-(3-chloropropoxy)benzoic acid (450 gm), formamide (2250 ml) and ammonium formate (200 gm) were heated to 170-180° C. for 3-4 hours. The reaction mass was concentrated under reduced pressure at 140-150° C. The residue was stirred in methanol (1000 ml) at 45-50° C. and cooled to 5-10° C. The solid obtained was filtered to yield the title compound (420 gm, 90% yield).

EXAMPLE 5 Preparation of 2-amino-4-methoxy-5-(3-chloropropoxy)benzoic acid (Formula IV) a) Preparation of 3-(3-chloropropoxy)-4-methoxy-6-nitrobenzoic acidMethanol (4 lt), 3-(3-chloropropoxy)-4-methoxy-6-nitro benzaldehyde (560 gm) and 30% methanolic NaOH solution (5 ml) were heated to 45° C. To this reaction mass 35% of H₂O₂solution (1200 ml) was added drop wise in 3-4 hours maintaining a pH of 10.5-11.5 with 30% methanolic NaOH solution. The reaction mass was quenched into ice water (10 kg) and the pH adjusted to 2.0-3.0 using hydrochloric acid. The solid obtained was filtered, washed with 50% aqueous methanol (500 ml) and dried at 45-50° C. to yield the title compound (510 gm, 86% yield).

bi) Preparation of 2-amino-4-methoxy-5-(3-chloropropoxy)benzoic acid—Using Hydrogen GasEthyl acetate (3 lt), Pd/C (50 gm) and 3-(3-chloropropoxy)-4-methoxy-6-nitrobenzoic acid (500 gm) were hydrogenated under a hydrogen pressure of 5-6 kg at 35-40° C. for 3-4 hours. The reaction mass was filtered and the clear filtrate was distilled under reduced pressure at 45-50° C. To the residue, hexane (1 lt) was charged, stirred at room temperature, the solids filtered and dried at 45-50° C. to yield the title compound (403 gm, 90% yield).

(bii) Preparation of 2-amino-4methoxy-5-(3-chloropropoxy)benzoic acid—Using Hydrazine Hydrate3-(3-chloropropoxy)-4-methoxy-6-nitrobenzoic acid (100 gm), hydrazine hydrate (50 gms), neutral alumina (20 gms), charcoal (10 gms), water (50 ml) and methanol (500 ml) were mixed together. The reaction mass was heated to 50° C. A solution of ferric chloride (2 gms, 0.012M) in 50 ml methanol was introduced slowly at 55-60° C. The reaction mass was filtered over hyflo and the clear filtrate evaporated. The residue obtained was dissolved in 1.0-lit ethyl acetate, washed organic extract with water, evaporated to obtain title compound. (75 gms, 83.6%)

(biii) Preparation of 2-amino-4-methoxy-5-(3-chloropropoxy)benzoic acid—Using Ammonium Formate3-(3-chloropropoxy)-4-methoxy-6-nitro benzoic acid (165 gms), 5% Paladium on carbon (16.5 gms) and DMF (0.66 lit) were mixed together. The reaction mass was heated to 40° C. Ammonium formate (82.5 gms) was charged in lots maintaining temperature below 50° C. The temperature of reaction mass slowly raised to 70° C. and maintained for 2 hours. The reaction mass was cooled to 30° C. and catalyst was removed by filtration and the clear filtrate evaporated. The residue was dissolved in ethyl acetate (0.825 lit), washed with water and evaporated to yield the title compound. (125 gms, 84.5%)

EXAMPLE 6 Preparation of 3-(3-chloropropoxy)-4-methoxy-6-nitro benzaldehyde (Formula III)5-nitro isovanillin (500 gm), acetonitrile (3.5 lts), K₂CO₃(750 gm) and chlorobromopropane (780 gm) were refluxed for 4 hours. The reaction mass was filtered hot, washed with acetonitrile (1 lt) and the filtrate was distilled off to remove solvent. The residue was dissolved in methylene chloride (4 lt) and washed with water. Water (3 lt) was charged to the methylene chloride layer, the pH adjusted to 7.0 to 7.5 with acetic acid, the methylene chloride layer separated, dried over sodium sulphate (50 gm) and distilled out completely under reduced pressure below 40° C. The residue was stirred with 2 volumes of n-Hexane at 40-45° C., cooled slowly to 0-5° C., the solids filtered, washed with n-Hexane (250 ml) and dried at 40-45° C. to yield the title compound (638 gm, 92% yield).

EXAMPLE 7 Preparation of 5-nitro isovanillin (Formula II)Isovanillin (500 gm) and acetic acid (1750 ml) were cooled to −5 to 0° C. To this solution, nitric acid (750 ml) was charged slowly at −5 to 0° C. with stirring. The temperature of the reaction mass was slowly raised to 25-30° C. and maintained for 12 hours. The reaction mass was quenched into ice water (4 kg), the solids filtered and washed with water (2 lt). The solids were stirred with a 1% sodium bicarbonate solution (1 lt), filtered and dried at 45-50° C. The solid was dissolved in 6 volumes of ethyl acetate, ethyl acetate was distilled off up to half the volume and 3 volumes of n-Hexane were charged slowly at 45-50° C. The reaction mass was cooled slowly to 0-5° C., maintained for 1 hour, the solids filtered, washed with 0.5 volumes of 1:1 mixture of ethyl acetate:n-Hexane and dried at 45-50° C. to yield the title compound (423 gm, 65% yield).

EXAMPLE 8 Preparation of Methyl-2-hydroxy-3-methoxy benzoate (Formula VIII) a) Preparation of 3-hydroxy-4-methoxy benzoic acidMethanol (350 ml), isovanillin (50 gm) and 30% methanolic sodium hydroxide solution (1 ml), were heated to 45° C. To this solution, 35% hydrogen peroxide solution (107 ml) was charged slowly maintaining pH at 10.5 to 11.5 using methanolic sodium hydroxide solution over a period of 2-3 hours. The reaction mass was quenched into chilled water (1 lt) and the pH adjusted to 2-3 using hydrochloric acid. The solids were filtered, washed with 50% aqueous methanol (50 ml) and dried at 45-50° C. to yield 3-hydroxy-4-methoxy benzoic acid.

b) Preparation of Methyl-2-hydroxy-3-methoxy benzoateThe solid obtained in step a), was refluxed with 10% methanolic hydrochloric acid solution (250 ml) for 6 hours. The reaction mass was quenched into chilled water (1 lt) and repeatedly extracted with methylene chloride (250 ml). The combined methylene chloride layer was washed with water (100 ml×2) and methylene chloride distilled out completely at 35-40° C. The residue was stirred in hexane (1.50 ml), at 25-30° C. The solid obtained was filtered, washed with: hexane (25 ml) and dried at 40-45° C. to yield the title compound (50 gm, 83% yield).

EXAMPLE 9 Preparation of Methyl-5-hydroxy-4-methoxy-2-nitro benzoate (Formula IX)Methyl-2-hydroxy-3-methoxy benzoate (50 gm) and acetic acid (175 ml) were cooled to 0-5° C. To this solution, 70% nitric acid solution (75 ml) was charged slowly at 0-5° C. under stirring and the reaction mass was further stirred for 18 hours. The reaction mass was quenched into chilled water (800 ml) and extracted repeatedly with methylene chloride (400 ml). The combined methylene chloride layer was washed with water, followed by 1% potassium carbonate solution (100 ml), dried over sodium sulphate and methylene chloride distilled off completely at 35-40° C. The residue was dissolved in 10% aqueous methanol (250 ml). The filtrate was gradually cooled to 0-5° C. and maintained for 1 hour. The solid obtained was filtered, washed with 10% aqueous methanol (100 ml) and dried at 40-45° C. to yield the title compound (46 gm, 74% yield).

EXAMPLE 10 Preparation of Methyl-2-amino-5-hydroxy-4-methoxy benzoate (X)Ethyl acetate (300 ml), methyl-5-hydroxy-4-methoxy-2-nitro benzoate (50 gm) and 10% palladium/carbon (5 gm) were hydrogenated under a hydrogen gas pressure of 5-6 kg for 4 hours. The reaction mass was filtered to remove catalyst. The filtrate was distilled off to remove solvent. The residue obtained was stirred in n-hexane (100 ml) at 0-5° C. The solid obtained was filtered and washed with n-hexane (25 ml) to yield the title compound (40 gm, 93% yield).

EXAMPLE 11 Preparation of 6-hydroxy-7-methoxy-quinazoline-4-one (formula XI)Methyl-2-amino-5-hydroxy-4-methoxy benzoate (50 gm), methanol (400 ml) and formamidine acetate (30 gm) were refluxed for 10 hours. The reaction mass was gradually cooled to 5-10° C. and stirred for 1 hour. The solid obtained was filtered and washed with methanol (150 ml) and dried at 50-55° C. to yield the title compound (45 gm, 92% yield).

Cited Patent	Filing date	Publication date	Applicant	Title
US6297257	17 Dec 1998	2 Oct 2001	Zambon Group S.P.A.	Benzazine derivatives phosphodiesterase 4 inhibitors
EP1477481A1	28 Jan 2003	17 Nov 2004	Ube Industries, Ltd.	Process for producing quinazolin-4-one derivative
IN901CHE2006A				Title not available
IN903CHE2006A				Title not available
WO1996033980A1	23 Apr 1996	31 Oct 1996	Zeneca Limited	Quinazoline derivatives
WO2004024703A1	9 Sep 2003	25 Mar 2004	Astrazeneca Ab	Process for the preparation of 4- (3’-chloro-4’-fluoroanilino) -7-methoxy-6- (3-morpholinopropoxy) quinazoline
WO2005023783A1	1 Sep 2004	17 Mar 2005	Astrazeneca Ab	Process for the manufacture of gefitinib
WO2005070909A1	27 Jul 2004	4 Aug 2005	Natco Pharma Limited	An improved process for the preparation of gefitinib
WO2008125867A2	16 Apr 2008	23 Oct 2008	Cipla Limited	Process for the preparation of gefitinib

/////////Gefitinib, US 8350029, CIPLA

PATENT, US 8344136, PHF S.A., Brinzolamide

PATENTS Comments Off

Sep 022016

Image result for Brinzolamide

US 8344136

http://www.google.co.in/patents/US8344136

PHF S.A., Lugano, Switzerland

Inventors	Alessandro Falchi, Ottorino De Lucchi, Andrea Castellin
Original Assignee	Phf S.A.

Process for the Preparation of Brinzolamide

Brinzolamide is a carbonic anhydrase II inhibitor, used to lower intraocular pressure and glaucoma. It is sold by Alcon under the name of Azopt, as 1% ophthalmic suspension.

EP 527801 claims Brinzolamide and describes a process to prepare it in 14 steps starting from 3-acetylthiophene (scheme 1). It is a synthesis typical of medicinal chemistry not applicable at industrial level, for which no specific preparations are described, because Brinzolamide is not among the preferred compounds of the invention.

This synthesis is not very efficient because requires the change of the oxidation status of the functional group in position 4 for three times; indeed this is first reduced with Sodium borohydride (step (5)) to α-bromoalcohol and then oxidized with Sodium dichromate (step (11)), a very toxic reagent. This sequence is necessary to obtain the cyclization (6), which brings only to degradation products on the ketone, and which requires a complex and not much efficient procedure as far as the quality and yield of the isolated product is concerned. The second reduction (12) occurs in the presence of (+)-β-chlorodiisopinocamphenylborane, an expensive enantioselective reducing agent, with a stoichiometric excess of 5:1, which requires reaction conditions not easily achievable at industrial scale (3 days of reaction at −22° C., difficult work up and chromatography) to isolate the product.

It can be inferred from the patent that there is the possibility to fix the stereogenic centre through selective crystallization of the salt of a chiral acid as di-p-toluoyl-D-tartaric acid, expensive resolution agent, with consequent loss of at least half of the substrate.

EP 617038 describes a process for the preparation of Brinzolamide and its analogues starting from 3-acetyl-2,5-dichlorothiophene (scheme 2).

The reduction (6) with (+)-β-chlorodiisopinocamphenylborane and the cyclization (7) bring to the optically active alcohol 2H-thieno[3,2-e]-1,2-thiazin-4-ol, 6-chloro-3,4-dihydro-, 1,1-dioxide, (4S)-. The formation of a product enriched with one of the enantiomer is too early in the synthesis, with a consequent risk of racemisation during the following steps, while the reduction would be more efficient if performed on a more advanced intermediate. The disadvantages of the use of the enantioselective reducing agent (6) and of the cyclization of the alcohol (7) are the same of the method described in Scheme 1. Another disadvantage is the alkylation (8) with 1-bromo-3-methoxypropane, that, in order to avoid the reaction of the oxydrilic group, is performed portionwise, with low temperatures and long reaction times.

The sulfonamide is introduced in position 6 through metallation with n-butyl lithium, an expensive raw material, and then with a reaction with sulphurous anhydride and hydroxylamino-O-sulphonic acid. The base should be used in substantial excess (2,3 eq.), because the oxydrilic group reacts with the first equivalent. In this case the protection of the oxydrilic group as described in Scheme 1 is not possible without running the risk of racemization of the substrate.

Lastly, the conversion of the secondary alcohol to the amine is difficult and requires the protection (10) of the primary sulfonamide with trimethyl orthoacetate, the activation (11) of the oxydrilic group with tosyl chloride and finally the substitution (12) of the tosyl group with ethylamine and at the same time the aminolysis of the protection of sulfonamide with the excess of ethylamine.

This synthesis is described in Org. Process Res. Dev. 3, 1999, 114, written by the R&D laboratories of Alcon. So it is reasonable to believe that this synthesis is used by Alcon at industrial level. Anyway, due to the low purity of the product obtained (97%), several crystallizations are needed to have a product of acceptable pharmaceutical grade.

U.S. Pat. No. 5,470,973 describes a variant of the synthesis in scheme 1, which involves an alternative preparation of the syntone 2H-thieno[3,2-e]-1,2-thiazin-4-ol, 6-chloro-3,4-dihydro-2-(3-methoxypropyl)-, 1,1-dioxide, (4S)- and the other analogues lacking chlorine in position 6 or the 3-methoxypropylic chain (scheme 3).

To introduce the chiral centre, firstly the oxidation (8) with dichromate is performed, and then the stereoselective reduction (9) with (S)-tetrahydro-1-methyl-3,3-diphenyl-1H,3H-pyrrol[1,2-c][1,3,2]oxazaborole are performed. The need of oxidizing first and then reducing was already commented in the description of the first synthetic path; the low enantiomeric excess (92%) is another disadvantage.

So it is evident the need of an alternative process for the preparation of Brinzolamide which can resolve the above mentioned technical problems.

OVERVIEW

Brinzolamide, 56, is used to treat glaucoma and can be synthesised by a 14-step route from acetylthiophene. This route is described as inefficient because of several changes of the oxidation state of one of the functional groups. Other routes have fewer steps but are still not very efficient. This patent describes a method for making compounds that are intermediates in the synthesis of56. The route is outlined in Schemes 20 and 21 and starts from the thiophene 49a or its chloro-derivative 49b (X = Cl). The first step is protection of the carbonyl group in 49a by reaction with 50to form 51a that is isolated in 87% yield. In the next step 51a is treated with K₂CO₃ to effect intermolecular cyclisation and formation of 52a. This can be obtained in 90% yield, or the reaction mixture can be treated with 53 without isolation of 52a to form 54a that is isolated 90% yield.

Scheme 20. ^a

^aReagents and conditions: (a) (i) TsOH, PhMe, reflux, 12 h; (ii) cool to rt, add Et₃N, separate; (iii) H₂O wash, evaporate. (b) (i) K₂CO₃, DMSO, 60 °C, 1 h; (ii) add H₂O/EtOAc, acidify to pH 7; (iii) separate, H₂O wash, evaporate. (c) (i) 60 °C, 8 h; (i) add H₂O/PhMe, separate; (iii)H₂O wash, evaporate.

The next stage is the introduction of the second sulphonamide group as shown in Scheme 21. This begins with treatment of 54a with BuⁿLi followed by addition of liquid SO₂. The intermediate reaction product is isolated as a solid and then treated with H₂NOSO₃H to form 54c that is recovered in 76% yield. The protective diol group is then removed by acid hydrolysis to give 55a in 97% yield. The conversion of 55a to 56 is not described in the patent, and reference to alternative syntheses of 56 indicate that this proceeds via asymmetric reduction of 56 to a hydroxy group that is then converted to the amine.

Scheme 21. ^a

^aReagents and conditions: (a) BuⁿLi, THF, −40 °C, 1 h; (ii) SO₂, −40 °C; (iii) warm to rt, evaporate; (iv) add H₂O, wash in DCM; (v) H₂NOSO₃H, NaOAc, H₂O, rt, 8 h; (vi) extract in EtOAc, wash in aq NaHCO₃, H₂O wash; (vii) evaporate. (b) (i) Aq HCl, PhMe, 80 °C, 16 h; (ii) separate, evaporate. (c) No details.

Compound 55a can be prepared by the same sequence of reactions shown in Schemes 20 and21 when starting from 49b. The yields of the corresponding intermediates are similar to or better than those reported for the method starting from 49a. The patent does not indicate the scale of the reactions, and the examples merely state the amounts of reactants used in terms of equivalents. The purity of the intermediates is not given, although ¹H NMR data are provided. The patent does not disclose how to obtain either of the starting materials, 49a or 49b, that are unlikely to be commercially available, and their synthesis will presumably add more steps to the synthesis of 56.

Advantages

The process provides an alternative route to the desired compound, but whether it is commercially viable and more efficient is not known.

Example 7 2′-(3-methoxypropyl)-2′,3′-dihydrospiro[1,3-dioxolan-2,4′-thieno[3,2-e][1,2]thiazin]-6′-sulphonamide, 1′,1′-dioxide 9 (X=sulphonamide)

The desired compound is prepared according to general procedure 4 starting from 2′-(3-methoxypropyl)-2′,3′-dihydrospiro[1,3-dioxolan-2,4′-thieno[3,2-e][1,2]thiazin], 1′,1′-dioxide of example 5 with a yield of 76%.

¹H-NMR (300 MHz, DMSO-d₆): 8.05 (s, 2H), 7.59 (s, 1H), 4.16 (m, 2H), 4.07 (m, 2H), 3.87 (s, 2H), 3.4-3.3 (m, 4H), 3.21 (s, 3H), 1.81 (m, 2H).

LC-MS: [M+H]⁺=399.

Example 8 2′-(3-methoxypropyl)-2′,3′-dihydrospiro[1,3-dioxolan-2,4′-thieno[3,2-e][1,2]thiazin]-6′-sulphonamide, 1′,1′-dioxide 9 (X=sulphonamide)

The desired compound is prepared according to general procedure 4 starting from 6′-chloro-2′-(3-methoxypropyl)-2′,3′-dihydrospiro[1,3-dioxolan-2,4′-thieno[3,2-e][1,2]thiazin], 1′,1′-dioxide of example 6 with a yield of 89%.

General Procedure 5 Hydrolisis of the Protective GroupThe compound of formula 5 is dissolved in toluene (10-20 volumes) and an aqueous solution of hydrochloric acid 2-12 N is added. The mixture is stirred at a temperature which can vary between 20° C. and 80° C. for a time between 2 and 16 ore, until complete hydrolysis. The phases are separated and the product 1 is isolated through distillation of the organic solvent under vacuum, obtaining a solid with a HPLC assay of 85-95% and a yield of 65-99%.

Example 9 4H-thieno[3,2-e]-1,2-thiazin-4-one, 2,3-dihydro-, 1,1-dioxide 1 (X and R=hydrogen)

The desired compound is prepared according to the general procedure 5 starting from 2′,3′-dihydrospiro[1,3-dioxolan-2,4′-thieno[3,2-e][1,2]thiazin], 1′,1′-dioxide of example 3 with a yield of 66%.

¹H-NMR (300 MHz, DMSO-d₆): 8.90 (bt, 1H), 7.98 (d, 1H), 7.46 (d, 1H), 4.23 (d, 2H).

LC-MS: [M+H]⁺=204.

Example 10 4H-thieno[3,2-e]-1,2-thiazin-4-one, 6-chloro 2,3-dihydro-, 1,1-dioxide 1 (X=chlorine and R=hydrogen)

The desired compound is prepared according to general procedure 5 starting from 6′-chloro-2′,3′-dihydrospiro[1,3-dioxolan-2,4′-thieno[3,2-e][1,2]thiazin], 1′,1′-dioxide of example 4 with a yield of 95%.

¹H-NMR (300 MHz, DMSO-d₆): 9.08 (bs, 1H), 7.56 (s, 1H), 4.26 (d, 2H).

GC-MS: [M]^+•=237.

Example 11 4H-thieno[3,2-e]-1,2-thiazin-4-one, 2,3-dihydro-2-(3-methoxypropyl)-, 1,1-dioxide 5 (X=hydrogen)

The desired compound is prepared according to the general procedure 5 starting from 2′-(3-methoxypropyl)-2′,3′-dihydrospiro[1,3-dioxolan-2,4′-thieno[3,2-e][1,2]thiazin], 1′,1′-dioxide of example 5 with a yield of 97%.

¹H-NMR (300 MHz, DMSO-d₆): 8.05 (d, 1H), 7.49 (m, 1H), 4.58 (s, 2H), 3.3-3.1 (m, 7H), 1.73 (m, 2H).

LC-MS: [M+H]⁺=276.

Example 12 4H-thieno[3,2-e]-1,2-thiazin-4-one, 6-chloro 2,3-dihydro-2-(3-methoxypropyl)-, 1,1-dioxide 5 (X=chlorine)

The desired compound is prepared according to the general procedure 5 starting from 6′-chloro-2′-(3-methoxypropyl)-2′,3′-dihydrospiro[1,3-dioxolan-2,4′-thieno[3,2-e][1,2]thiazin], 1′,1′-dioxide of example 6 with a yield of 99%.

¹H-NMR (300 MHz, DMSO-d₆): 7.59 (s, 1H), 4.50 (s, 2H), 3.3-3.2 (m, 4H), 3.18 (s, 3H), 1.74 (m, 2H).

LC-MS: [M+H]⁺=310.

Example 13 2H-thieno[3,2-e]-1,2-thiazin-6-sulphonamide, 3,4-dihydro-2-(3-methoxypropyl)-4-oxo-, 1,1-dioxide 5 (X=Sulphonamide)

The desired compound is prepared according to the general procedure 5 starting from 2′-(3-methoxypropyl)-2′,3′-dihydrospiro[1,3-dioxolan-2,4′-thieno[3,2-e][1,2]thiazin]-6′-sulphonamide, 1′,1′-dioxide of examples 7 or 8 with a quantitative yield.

¹H-NMR (300 MHz, DMSO-d₆): 8.20 (s, 2H), 7.77 (s, 1H), 4.54 (s, 2H), 3.4-3.1 (m, 7H), 1.78 (m, 2H).

LC-MS: [M+H]⁺=355.

///////////PATENT, US 8344136, PHF S.A., Brinzolamide