GSK-2041706A, Potent GPR119 Receptor Agonists

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Jul 312016

GSK-2041706A

[2-([(1S)-1-(1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl)ethyl]oxy)-5-[4-(methylsulfonyl)phenyl]pyrazine]

2-[((1S)-1-{1-[3-(1-Methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}ethyl)oxy]-5-[4-(methylsulfonyl)phenyl]pyrazine

CAS 1032824-43-3

Potent GPR119 Receptor Agonists

Molecular Formula:	C₂₃H₂₉N₅O₄S
Molecular Weight:	471.57246 g/mol

G protein-coupled receptor 119 (GPR119) is a G protein-coupled receptor expressed predominantly in pancreatic β-cells and gastrointestinal enteroendocrine cells. Metformin is a first-line treatment of type 2 diabetes, with minimal weight loss in humans. In this study, we investigated the effects of GSK2041706 [2-([(1S)-1-(1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl)ethyl]oxy)-5-[4-(methylsulfonyl)phenyl]pyrazine], a GPR119 agonist, and metformin as monotherapy or in combination on body weight in a diet-induced obese (DIO) mouse model. Relative to vehicle controls, 14-day treatment with GSK2041706 (30 mg/kg b.i.d.) or metformin at 30 and 100 mg/kg b.i.d. alone caused a 7.4%, 3.5%, and 4.4% (all P < 0.05) weight loss, respectively. The combination of GSK2041706 with metformin at 30 or 100 mg/kg resulted in a 9.5% and 16.7% weight loss, respectively. The combination of GSK2041706 and metformin at 100 mg/kg caused a significantly greater weight loss than the projected additive weight loss of 11.8%. This body weight effect was predominantly due to a loss of fat. Cumulative food intake was reduced by 17.1% with GSK2041706 alone and 6.6% and 8.7% with metformin at 30 and 100 mg/kg, respectively. The combination of GSK2041706 with metformin caused greater reductions in cumulative food intake (22.2% at 30 mg/kg and 37.5% at 100 mg/kg) and higher fed plasma glucagon-like peptide 1 and peptide tyrosine tyrosine levels and decreased plasma insulin and glucose-dependent insulinotropic polypeptide levels compared with their monotherapy groups. In addition, we characterized the effect of GSK2041706 and metformin as monotherapy or in combination on neuronal activation in the appetite regulating centers in fasted DIO mice. In conclusion, our data demonstrate the beneficial effects of combining a GPR119 agonist with metformin in the regulation of body weight in DIO mice.

Diabetes mellitus is an ever-increasing threat to human health. For example, in the United States current estimates maintain that about 16 million people suffer from diabetes mellitus.

Type I diabetes, also known as insulin-dependent diabetes mellitus (IDDM), is caused by the autoimmune destruction of the insulin producing pancreatic β-cells, and necessitates regular administration of exogenous insulin. Without insulin, cells cannot absorb sugar (glucose), which they need to produce energy. Symptoms of Type I diabetes usually start in childhood or young adulthood. People often seek medical help because they are seriously ill from sudden symptoms of high blood sugar (hyperglycemia).

Type II diabetes, also known as non-insulin-dependent diabetes mellitus (NIDDM), manifests with an inability to adequately regulate blood-glucose levels. Type II diabetes may be characterized by a defect in insulin secretion or by insulin resistance, namely those that suffer from Type II diabetes have too little insulin or cannot use insulin effectively. Insulin resistance refers to the inability of body tissues to respond properly to endogenous insulin. Insulin resistance develops because of multiple factors, including genetics, obesity, increasing age, and having high blood sugar over long periods of time. Type II diabetes, sometimes called mature or adult onset diabetes, can develop at any age, but most commonly becomes apparent during adulthood. The incidence of Type II diabetes in children, however, is rising

In diabetics, glucose levels build up in the blood and urine causing excessive urination, thirst, hunger, and problems with fat and protein metabolism. If left untreated, diabetes mellitus may cause life-threatening complications, including blindness, kidney failure, and heart disease.

Type II diabetes accounts for approximately 90-95% of diabetes cases, killing about 193,000 U.S. residents each year. Type II diabetes is the seventh leading cause of all deaths. In Western societies, Type II diabetes currently affects 6% of the adult population with world-wide frequency expected to grow by 6% per annum.

Although there are certain inheritable traits that may predispose particular individuals to developing Type II diabetes, the driving force behind the current increase in incidence of the disease is the increased sedentary lifestyle, diet, and obesity now prevalent in developed countries. About 80% of diabetics with Type II diabetes are significantly overweight. As noted above, an increasing number of young people are developing the disease. Type II diabetes is now internationally recognized as one of the major threats to human health in the 21^stcentury.

Type II diabetes currently is treated at several levels. A first level of therapy is through the use of diet and/or exercise, either alone or in combination with therapeutic agents. Such agents may include insulin or pharmaceuticals that lower blood glucose levels. About 49% of individuals with Type II diabetes require oral medication(s), about 40% of individuals require insulin injections or a combination of insulin injections and oral medication(s), and about 10% of individuals may use diet and exercise alone.

Current therapies for diabetes mellitus include: insulin; insulin secretagogues, such as sulphonylureas, which increase insulin production from pancreatic-cells; glucose-lowering effectors, such as metformin which reduce glucose production from the liver; activators of the peroxisome proliferator-activated receptor—(PPAR-), such as the thiazolidinediones, which enhances insulin action; and α-glucosidase inhibitors which interfere with gut glucose production. There are, however, deficiencies associated with currently available treatments, including hypoglycemic episodes, weight gain, loss in responsiveness to therapy over time, gastrointestinal problems, and edema.

There are several areas at which research is being targeted in order to bring new, more effective, therapies to the marketplace. For example, on-going research includes exploring a reduction in excessive hepatic glucose production, enhancing the pathway by which insulin transmits its signal to the cells such that they take up glucose, enhancing glucose-stimulated insulin secretion from the pancreatic-cells, and targeting obesity and associated problems with fat metabolism and accumulation.

One particular target is GPR119. GPR119 is a member of the rhodopsin family of G-protein-coupled receptors. In addition to the “GPR119” identifier, several other identifiers exist, including but not limited to RUP 3, Snorf 25, 19 AJ, GPR 116 (believed to be erroneous), AXOR 20, and PS1. GPR119 is expressed in human gastrointestinal regions and in human islets. Activation of GPR119 has been demonstrated to stimulate intracellular cAMP and lead to glucose-dependent GLP-1 and insulin secretion. See, T. Soga et al., Biochemical and Biophysical Research Communications 326 (2005) 744-751, herein incorporated by reference with regard to a background understanding of GPR119.

In type 2 diabetes the action of GLP-1 on the β-cell is maintained, although GLP-1 secretion, itself, is reduced. More recently, therefore, much research has been focused on GLP-1. Studies show glucose-lowering effects in addition to GLP-1’s ability to stimulate glucose-dependent insulin secretion including, but not limited to, an inhibition of the release of the hormone glucagon following meals, a reduction in the rate at which nutrients are absorbed into the bloodstream, and a reduction of food intake. Studies demonstrate that treatments to increase GLP-1, therefore, may be used for a variety of conditions and disorders including but not limited to metabolic disorders, gastrointestinal disorders, inflammatory diseases, psychosomatic, depressive, and neuropsychiatric disease including but not limited to diabetes mellitus (Type 1 and Type 2), metabolic syndrome, obesity, appetite control and satiety, weight loss, stress, inflammation, myocardial ischemia/reperfusion injury, Alzheimer’s Disease, and other diseases of the central nervous system.

The use of exogenous GLP-1 in clinical treatment is severely limited, however, due to its rapid degradation by the protease DPP-IV. There are multiple GLP-1 mimetics in development for type 2 diabetes that are reported in the literature, all are modified peptides, which display longer half-lives than endogenous GLP-1. For example, the product sold under the tradename BYETTA® is the first FDA-approved agent of this new class of medications. These mimetics, however, require injection. An oral medication that is able to elevate GLP-1 secretion is desirable. Orally available inhibitors of DPP-IV, which result in elevation in intact GLP-1, are now available, such as sitagliptin, marketed under the brand name JANUVIA®. Nevertheless, a molecule which may stimulate GLP-1 secretion would provide a therapeutic benefit. A molecule which could stimulate both GLP-1 secretion and insulin secretion through effects on the L-cell and direct effects on the β-cell would hold much promise for type 2 diabetes therapy.

The present invention identifies agonists of GPR119 which increase glucose-disposal in part through elevation of GIP, GLP-1, and insulin. Moreover, studies demonstrate that GPR119 agonists such as the compounds of the present invention can stimulate incretins independently of glucose. GIP and GLP-1 are peptides, known as incretins, secreted from enteroendocrine K and L cells, respectively, in response to ingestion of nutrients, and have a wide variety of physiological effects that have been described in numerous publications over the past two decades. See, for example, Bojanowska, E. et al.,Med. Sci. Monit., 2005, August 11(8): RA271-8; Perry, T. et al., Curr. Alzheimer Res., 2005, July 2(3): 377-85; and Meier, J. J. et al.,Diabetes Metab. Res. Rev., 2005, March-April; 21(2); 91-117 (each herein incorporated by reference with regard to a background understanding of incretins). Moreover, although the mechanisms regulating GLP-1 secretion remain unclear, the initial rapid rise in GLP-1 following a meal may be a result of hormonal stimulation of neuronal afferents involving GIP. See, for example, J. N. Roberge and P. L. Brubaker, Endocrinology 133 (1993), pp. 233-240 (herein incorporated by reference with regard to such teaching). Furthermore, later increases in GLP-1 may involve direct activation of L-cells by nutrients in the distal small-intestine and the colon. GIP and GLP-1 are potent stimulators of the body’s ability to produce insulin in response to elevated levels of blood sugar. In Type 2 diabetes, patients display a decreased responsiveness to GIP but not GLP-1, with respect to its ability to stimulate insulin secretion. The mechanism behind the decreased responsiveness to GIP remains unclear since type 2 diabetics retain sensitivity to a bolus administration of GIP but not to a continuous infusion (Meier et al. 2004 Diabetes 53 S220-S224). Moreover recent studies with a long-acting fatty-acid derivative of GIP showed beneficial effects on glucose homeostasis in ob/ob mice following 14 days of treatment (Irwin N. et al. (2006) J. Med. Chem. 49, 1047-1054.)

Agonists to GPR119 may be of therapeutic value for diabetes and associated conditions, particularly type II diabetes, obesity, glucose intolerance, insulin resistance, metabolic syndrome X, hyperlipidemia, hypercholesterolemia, and atherosclerosis.

NMR

¹H NMR (400 MHz, DMSO-d₆) δ 8.91 (bs, 1H), 8.40 (bs, 1 H), 8.28 (d, J = 8.5 Hz, 2H), 8.02 (d, J = 8.5 Hz, 2H), 5.17–5.09 (m, 1H), 4.09–3.95 (m, 2H), 3.27 (s, 3H), 3.16–2.99 (m, 2H), 2.80 (q, J = 6.9 Hz, 1H), 1.98–1.85 (m, 2H), 1.83–1.70 (m, 1H), 1.47–1.33 (m, 2H), 1.31 (d, J = 6.3 Hz, 3H), 1.17 (d, J = 6.8 Hz, 6H).

¹³C NMR (100.6 MHz, DMSO-d₆) 175.3, 170.9, 159.8, 142.6, 141.2, 141.0, 139.1, 135.7, 128.1, 126.9, 75.7, 46.0, 45.9, 44.0, 40.2, 27.1, 27.0, 26.7, 20.7, 16.9.

HRMS calcd for C₂₃H₃₀N₅O₄S (M + H)⁺ 472.2013, found, 472.2009.

PATENT

Jing Fang, Jun Tang, Andrew J. Carpenter,Gregory Peckham, Christopher R. Conlee,Kien S. Du, Subba Reddy Katamreddy,

http://www.google.co.ug/patents/US20120077812

Example 156(±)-2-[(1-{1-[3-(1-Methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}ethyl)oxy]-5-[4-(methylsulfonyl)phenyl]pyrazine

Step 1: A solution of 3-(1-methylethyl)-5-(trichloromethyl)-1,2,4-oxadiazole (prepared as in Example 158, Alternative synthesis, Step 3, 179 g, 0.78 mol) in MeOH (300 mL) was treated with 4-piperidinemethanol (108 g, 0.94 mol) and stirred and heated at 50° C. overnight. The solvent was removed and the residue was purified by flash chromatography on a silica gel column to give {1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}methanol (60 g, 34%) as a pale yellow oil.

Step 2: A solution of {1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}methanol (1.50 g, 6.66 mmol) in CH₂Cl₂(50 mL) at 0° C. was treated with Dess-Martin periodinane (2.91 g, 6.66 mmol). The reaction mixture was warmed to ambient temperature and stirred overnight. The reaction was quenched with aqueous 20% Na₂S₂O₃(100 mL) and aqueous saturated NaHCO₃(100 mL) and then stirred for 10 minutes. The CH₂Cl₂layer was separated and washed with brine, dried over Na₂SO₄, filtered, and the filtrate was concentrated to give the crude product as a cloudy colorless oil. The crude product was dissolved in 100 mL of 1:1 EtOAc/hexanes, filtered through a pad of silica gel, washed with 200 mL of 1:1 EtOAc/hexanes. The filtrate was concentrated to give 1.07 g (72%) of 1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinecarbaldehyde as a clear colorless oil, which was used without further purification. ¹H NMR (400 MHz, CDCl₃): δ 9.68 (s, 1H), 4.15-4.00 (m, 2H), 3.30-3.20 (m, 2H), 2.86 (septet, 1H, J=7.0 Hz), 2.55-2.45 (m, 1H), 2.10-1.95 (m, 2H), 1.80-1.65 (m, 2H), 1.26 (d, 6H, J=6.8 Hz).

Step 3: (±)-1-{1-[3-(1-Methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}ethyl methanesulfonate (0.74 g, 49%) was prepared as a light brown oil from 1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinecarbaldehyde (1.07 g, 4.79 mmol) and methylmagnesium bromide (3M in Et₂O, 3.51 mL, 10.54 mmol) then methanesulfonyl chloride (0.22 mL, 2.81 mmol) and Et₃N (0.66 mL, 4.68 mmol) in a manner similar to Example 139, Steps 1-2. The crude product was used without further purification. ¹H NMR (400 MHz, CDCl₃): δ 4.70-4.60 (m, 1H), 4.30-4.15 (m, 2H), 3.10-2.95 (m, 5H), 2.87 (septet, 1H, J=7.0 Hz), 1.95-1.70 (m, 3H), 1.55-1.35 (m, 5H), 1.26 (d, 6H, J=6.8 Hz).

Step 4: The title compound (0.212 g, 26%) was prepared as a white foam from 5-[4-(methylsulfonyl)phenyl]-2-pyrazinol (and tautomers thereof) (prepared as in Example 145, Steps 1-2, 0.43 g, 1.72 mmol), (±)-1-{1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}ethyl methanesulfonate (0.74 g, 2.32 mmol) and K₂CO₃(0.48 g, 3.44 mmol) in DMF (15 mL) in a manner similar to Example 152, Steps 3. The crude product was purified by chromatography on an ISCO silica gel column using 0 to 25% EtOAc/CH₂Cl₂, followed by chromatography on a silica gel column eluted with 50% EtOAc/hexanes to give (±)-2-[(1-{1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}ethypoxy]-5-[4-(methylsulfonyl)phenyl]pyrazine as a white solid. ¹H NMR (400 MHz, CDCl₃): δ 8.53 (s, 1H), 8.25 (s, 1H), 8.10 (d, 2H, J=8.5 Hz), 8.02 (d, 2H, J=8.5 Hz), 5.20-5.10 (m, 1H), 4.35-4.20 (m, 2H), 3.15-3.00 (m, 5H), 2.91 (septet, 1H, J=7.0 Hz), 2.00-1.80 (m, 3H), 1.60-1.40 (m, 2H), 1.34 (d, 3H, J=6.1 Hz), 1.28 (d, 6H, J=7.1 Hz); LRMS (ESI), m/z 472 (M+H).

Example 1572-[((1R)-1-{1-[3-(1-Methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}ethyl)oxy]-5-[4-(methylsulfonyl)phenyl]pyrazin

The racemic 2-[(1-{1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}ethyl)oxy]-5-[4-(methylsulfonyl)phenyl]pyrazine (prepared as in Example 156) was subjected to Chiral HPLC [column: AS-H, column mobile phase: 70% CO₂: 30% MeOH (2 mL/min), pressure 140 bar, temperature 40° C., 215 nm] analysis and then separated to give two (R and S) enantiomers. The title compound was isolated as an off-white solid with Tr of 23.42 min (first eluting peak). The (R) absolute stereochemistry was assigned by Ab initio VCD analysis.

Example 158

2-[((1S)-1-{1-[3-(1-Methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}ethyl)oxy]-5-[4-(methylsulfonyl)phenyl]pyrazine

The racemic 2-[(1-{1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}ethyl)oxy]-5-[4-(methylsulfonyl)phenyl]pyrazine (prepared as in Example 156) was subjected to Chiral HPLC [column: AS-H, column mobile phase: 70% CO₂: 30% MeOH (2 mL/min), pressure 140 bar, temperature 40° C., 215 nm] analysis and then separated to give two (R and S) enantiomers. The title compound was isolated as an off-white solid with Tr of 25.83 min (second eluting peak). The (S) absolute stereochemistry was assigned by Ab initio VCD analysis. Alternative preparation from enantiomerically enriched material:

Step 1: Triethylamine (315 mL, 2.26 mol) was added dropwise to formic acid (150 mL, 3.91 mol) with overhead stirring while maintaining the internal temperature below 60° C. with ice-bath cooling. Neat 4-acetylpyridine (100 mL, 0.904 mol) was then added rapidly while maintaining the temperature below 50° C. Following this addition, the reaction was allowed to cool to 28° C. and the chiral ruthenium catalyst [N-[(1R,2R)-2-(amino-N)-1,2-diphenylethyl]-2,4,6-trimethylbenzenesulfonamidato-N]chloro[(1,2,3,4,5,6-n)-1-methyl-4-(1-methylethyl)benzene]ruthenium (CAS#177552-91-9; for catalyst preparation, see: Uematsu, N.; Fujii, A.; Hashiguchi, S.; Ikariya, T.; Noyori, R.; J. Am. Chem. Soc. 1996, 118, 4916-4917) (3 g, 4.46 mmol) was added. The mixture was stirred under house vacuum for 4 h and then overnight under an atmosphere of nitrogen. The reaction mixture was added dropwise to a stirred solution of 10% Na₂CO₃(4 L) and then extracted with EtOAc (3×1 L). The combined EtOAc layers were washed once with brine (1 L), treated with MgSO₄and Darco G-60 decolorizing charcoal and filtered through a 100 g plug of silica gel washing with 10% MeOH/EtOAc (1 L). The filtrate was concentrated to provide a dark oil that crystallized upon standing. The solid was dissolved in warm t-butyl methyl ether (250 mL) and the warm solution was filtered to remove a small amount of insoluble material. The filtrate was allowed to stir with cooling to room temperature and then to −15° C. The solids were collected by filtration, washing with cold t-butyl methyl ether and heptane, and then dried under high vacuum to yield (1R)-1-(4-pyridinyl)ethanol as a dark beige solid (62 g, 52.9% yield). This solid material was 96% ee based on chiral HPLC(HPLC conditions: AS-H column, 5% MeOH/CO₂, 40° C., 140 bar, 2 mL/min). The filtrate was combined with the insoluble solid from the crystallization and concentrated in vacuo to yield additional (1R)-1-(4-pyridinyl)ethanol as a dark oil (37.5 g, 32% yield). This oily material was 78% ee based on chiral HPLC (see HPLC conditions above). ¹H NMR (400 MHz, DMSO-d₆): δ 8.47-8.43 (m, 2H), 7.32-7.28 (m, 2H), 5.37 (d, 1H, J=4.4 Hz), 4.72-4.64 (m, 1H), 1.44 (d, 3H, J=6.6 Hz).

Step 2: A solution of (1R)-1-(4-pyridinyl)ethanol (37 g, 0.3 mol, 78% ee) in MeOH (2 L) was charged with PtO₂(5 g) under nitrogen atmosphere followed by acetic acid (19 mL). The mixture was evacuated and purged with hydrogen several times and then stirred under an atmosphere of hydrogen for 2 d at room temperature. The mixture was filtered to remove catalyst and the filtrate was concentrated in vacuo and triturated with EtOAc to yield a cream-colored solid which was collected by filtration. The filter cake was dissolved in MeOH (500 mL) and 50% NaOH (15.8 g) was added. The resulting solution was stirred at 25° C. for 30 min and concentrated. The resulting solid was triturated with Et₂O (700 mL) and stirred at 25° C. for 30 min, the solids were removed by filtration and the filtrate was dried over MgSO₄and filtered again. The final filtrate was concentrated to yield (1R)-1-(4-piperidinyl)ethanol (22 g, 57% yield) as a light beige solid. ¹H NMR (400 MHz, CDCl₃): δ 3.50 (quint, 1H, J=6.3 Hz), 3.13-3.01 (m, 2H), 2.61-2.47 (m, 2H), 1.88 (br, 2H), 1.84-1.73 (m, 1H), 1.63-1.52 (m, 1H), 1.41-1.27 (m, 1H), 1.23-1.05 (m, 2H), 1.13 (d, 3H, J=6.2 Hz).

Step 3: A stirred solution of N-hydroxy-2-methylpropanimidamide (16.33 g, 160 mmol) in pyridine (16.81 mL, 208 mmol) and dichloromethane (165 mL) at −15° C. was treated with trichloroacetyl chloride (19.63 mL, 176 mmol) over 40 min. The reaction was allowed to warm to ambient temperature and stirred for 42 h. Water (100 mL) was added and the reaction was stirred for 30 min. The dichloromethane was removed and the residue was diluted with water (50 mL) and extracted with ether (300 mL). The ether layer was washed with water, dried over MgSO₄and concentrated to afford 3-(1-methylethyl)-5-(trichloromethyl)-1,2,4-oxadiazole (28.0 g, 76% yield) as an orange liquid.¹H NMR (400 MHz, CDCl₃): δ 3.13 (septet, 1H, J=7.0 Hz), 1.36 (d, 6H, J=7.0 Hz).

Step 4: A solution of 3-(1-methylethyl)-5-(trichloromethyl)-1,2,4-oxadiazole (25.8 g, 112 mmol) and (1R)-1-(4-piperidinyl)ethanol (13.4 g, 104 mmol) in MeOH (15 mL) was stirred at ambient temperature under a stream of nitrogen for 7 days. The reaction was diluted with MeOH (40 mL), cooled in an ice bath and 1N NaOH (25 mL) was added. The mixture was allowed to warm to ambient temperature and stir for 1 h. The reaction was partitioned in EtOAc (300 mL)/1N NaOH (75 mL) and the layers were separated. The aqueous layer was saturated with NaCl and extracted with EtOAc (200 mL). The combined EtOAc layers were dried over MgSO₄, concentrated and placed under high vacuum for 18 h to afford (1R)-1-{1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}ethanol (16.75 g, 68%) as an orange oil. ¹H NMR (400 MHz, CDCl₃): δ 4.14 (m, 2H), 3.57 (quint, 1H, J=6.3 Hz), 2.98 (m, 2H), 2.83 (septet, 1H, J=7.0 Hz), 1.90 (m, 1H), 1.86 (br, 1H), 1.67 (m, 1H), 1.45 (m, 1H), 1.33 (m, 2H), 1.23 (d, 6H, J=7.0 Hz), 1.16 (d, 3H, J=6.3 Hz); LRMS (ESI), m/z 240 (M+H).

Step 5: A solution of (1R)-1-{1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}ethanol (1.68 g, 7.0 mmol) in dichloromethane (100 mL) at 0° C. was treated with Et₃N (1.98 mL, 14.0 mmol) followed by methanesulfonyl chloride (0.66 mL, 8.4 mmol). The mixture was stirred at 0° C. for 1 h, then at room temperature for 2 h. The mixture was diluted with dichloromethane (50 mL), washed with 1M NaH₂PO₄(75 mL×2) and brine, and dried over Na₂SO₄and concentrated to give (1R)-1-{1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}ethyl methanesulfonate (2.23 g, 7.0 mmol, 100% yield) as a brown oil, which was used without further purification.

Step 6: A mixture of 5-[4-(methylsulfonyl)phenyl]-2-pyrazinol (and tautomers thereof) (prepared as in Example 145, Step 2, 1.3 g, 5.19 mmol), (1R)-1-{1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}ethyl methanesulfonate (2.23 g, 7.0 mmol, 70% ee) and K₂CO₃(1.45 g, 10.4 mmol) in DMF (35 mL) was stirred at 100° C. in a preheated oil bath overnight. The mixture was cooled to ambient temperature, treated with water, and the mixture was extracted with EtOAc (75 mL×2). The combined organic extracts were washed with water, brine and dried over Na₂SO₄, filtered, and the filtrate was concentrated to a brown oil, which was by chromatography on a silica gel column eluted with 50% EtOAc/hexanes followed by chromatography on an ISCO silica gel column using 0 to 60% EtOAc/hexanes to give 2-[((1S)-1-{1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}ethyl)oxy]-5-[4-(methylsulfonyl)phenyl]pyrazine (0.73 g, 70% ee, 30%) as a white solid. The solid was subjected to chiral separation (similar to conditions used above for Example 158) to yield 0.30 g of the title compound as a white solid. ¹H NMR (400 MHz, CDCl₃): δ 8.53 (d, 1H, J=1.3 Hz), 8.25 (d, 1H, J=1.3 Hz), 8.10 (d, 2H, J=8.3 Hz), 8.02 (d, 2H, J=8.5 Hz), 5.20-5.10 (m, 1H), 4.35-4.20 (m, 2H), 3.15-3.00 (m, 5H), 2.90 (septet, 1H, J=7.0 Hz), 2.00-1.80 (m, 3H), 1.60-1.40 (m, 2H), 1.34 (d, 3H, J=6.3 Hz), 1.28 (d, 6H, J=6.9 Hz); LRMS (ESI), m/z 472 (M+H).

Paper

Development of Large-Scale Routes to Potent GPR119 Receptor Agonists

Richard T. Matsuoka^*†, Eric E. Boros#, Andrew D. Brown†, Kae M. Bullock†, Will L. Canoy‡, Andrew J. Carpenter#, Jeremy D. Cobb†, Shannon E. Condon†, Nicole M. Deschamps†, Vassil I. Elitzin†, Greg Erickson†,Jing M. Fang#, David H. Igo§, Biren K. Joshi‡, Istvan W. Kaldor#, Mark B. Mitchell†, Gregory E. Peckham#, Daniel W. Reynolds‡, Matthew C. Salmon†, Matthew J. Sharp†, Elie A. Tabet#, Jennifer F. Toczko†, Lianming Michael Wu‡, and Xiao-ming M. Zhou†

^†API Chemistry Department, ^‡Analytical Science & Development Department, ^#Medicinal Chemistry Department, and^§Particle Sciences and Engineering Department, GlaxoSmithKline, 709 Swedeland Road, King of Prussia, Pennsylvania 19406, United States

Org. Process Res. Dev., Article ASAP

DOI: 10.1021/acs.oprd.6b00157, http://pubs.acs.org/doi/abs/10.1021/acs.oprd.6b00157

Publication Date (Web): July 13, 2016

*E-mail: richard.t.matsuoka@gsk.com.

Abstract

Practical and scalable syntheses were developed that were used to prepare multikilogram batches of GSK1292263A (1) and GSK2041706A (15), two potent G protein-coupled receptor 119 (GPR119) agonists. Both syntheses employed relatively cheap and readily available starting materials, and both took advantage of an S_NAr synthetic strategy.

Patent ID	Date	Patent Title
US2012077812	2012-03-29	BICYCLIC COMPOUNDS AND USE AS ANTIDIABETICS
US8101634	2012-01-24	BICYCLIC COMPOUNDS AND USE AS ANTIDIABETICS

/////////////GSK2041706A, GSK 2041706A, GSK-2041706A, GSK2041706, GSK 2041706, GSK-2041706

Supporting Info

O=S(c4ccc(c3cnc(OC(C2CCN(c1nc(C(C)C)no1)CC2)C)cn3)cc4)(C)=O

GSK-1292263A Glucose-Dependent Insulinotropic Receptor (GDIR, GPR119) Agonists

phase 2, Uncategorized Comments Off

Jul 312016

str1

GSK-1292263

CAS 1032823-75-8

3-isopropyl-5-(4-(((6-(4-(methylsulfonyl)phenyl)pyridin-3-yl)oxy)methyl)piperidin-1-yl)-1,2,4-oxadiazole

5-[1-(3-Isopropyl-1,2,4-oxadiazol-5-yl)piperidin-4-ylmethoxy]-2-[4-(methylsulfonyl)phenyl]pyridine

5-[({1-[3-(1-Methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}methyl)oxy]-2-[4-(methylsulfonyl)phenyl]pyridine

MF C23H28N4O4S

MW: 456.18313

1292263
GSK-1292263
GSK-1292263A
GSK-263A

Smithkine Beecham Corp, INNOVATOR

GSK-1292263 is a novel GPR119 receptor agonist that is currently under development for the treatment of type 2 diabetes. Treatment of male Sprague-Dawley rats with a single dose of GSK-1292263 (3-30 mg/kg) in the absence of nutrients correlated with increased levels of circulating gastrointestinal peptides; glucagon-like peptide 1 (GLP-1), gastric inhibitory polypeptide (GIP), peptide YY (PYY) and glucagon.

GSK-1292263 had been evaluated in phase II clinical studies at GlaxoSmithKline for the oral treatment of type 2 diabetes and as monotherapy or in combination with sitagliptin for the treatment of dyslipidemia; however no recent development has been reported for this research.

Following administration of glucose in the oral glucose tolerance test (OGTT), greater increases in total GLP-1, GIP and PYY were seen in GSK-1292263-treated rats than in control animals. Despite significant decreases in the glucose AUC, no statistically significant differences in insulin responses and insulin AUC were observed between rats administered GSK-1292263 and those receiving vehicle control.

In the intravenous glucose tolerance test, significant increases in the peak insulin response and insulin AUC(0-15 min) of 30-60% were reported in the GSK-1292263 treatment group, compared with values in the vehicle control cohort. This insulin upregulation correlated with a significant increase in the glucose disposal rate (Brown, K.K. et al. Diabetes [70th Annu Meet Sci Sess Am Diabetes Assoc (ADA) (June 25-29, Orlando) 2010] 2010, 59(Suppl. 1): Abst 407).

The safety, tolerability, pharmacokinetics and pharmacodynamics of single and multiple oral doses of GSK-1292263 were evaluated in a recently completed randomized, placebo-controlled clinical trial in healthy volunteers (ClinicalTrials.gov Identifier NCT00783549).

A total of 69 subjects received single escalating doses of GSK-1292263 (10-400 mg) prior to administration of a 250-mg dose given once daily for 2 and 5 days, which was also evaluated in combination with sitagliptin (100 mg). Treatment with GSK-1292263 at all doses was described as well tolerated, with the most common drug-related effects being mild headache, dizziness, hyperhidrosis, flushing and post-OGTT hypoglycemia.

NMR

¹H NMR (400 MHz, DMSO-d₆) δ 8.44 (d, J = 3.0 Hz, 1H), 8.28 (d, J = 8.8 Hz, 2H), 8.06 (d, J = 8.8 Hz, 1H), 7.99 (bd, J = 8.5 Hz, 2H), 7.54 (dd, J = 8.8, 3.0 Hz, 1H), 4.03 (d, J = 6.3 Hz, 2H), 4.03–3.97 (m, 2H), 3.25 (s, 3H), 3.20–3.09 (m, 2H), 2.81 (q, J = 6.7 Hz, 1H), 2.13–2.00 (m, 1H), 1.88 (bd, J = 12.8 H, 2H), 1.42–1.29 (m, 2H), 1.18 (d, J = 7.0 Hz, 6H).

¹³C NMR (100.6 MHz, DMSO-d₆) 175.3, 170.9, 155.5, 147.0, 143.5, 140.5, 138.6, 127.9, 127.0, 122.4, 122.3, 72.5, 45.7, 44.1, 35.0, 28.0, 26.7, 20.8.

HRMS calcd for C₂₃H₂₉N₄O₄S (M + H)⁺ 457.1904, found, 457.1900.

Anal. Calcd for C₂₃H₂₈N₄O₄S: C, 60.51; H, 6.18; N, 12.27. Found: C, 60.64; H, 6.16; N, 12.24.

str1

Hypoglycemia was not reported with the 5-day dosing schedule. Pharmacokinetic profiling revealed dose-proportional AUC and Cmax at single lower doses, but not at single higher ones. Following repeated once-daily dosing (5 days), drug accumulation was observed consistent with a mean half-life of 12-18 hours. A dose-dependent increase in glucose AUC(0-3 h) during OGTT was seen in GSK-1292263-treated subjects. The treatment was also associated with an increase in PYY during the prandial periods.

Coadministration with sitagliptin led to increases in the plasma concentrations of active GLP-1 but reduced the levels of total GLP-1, GIP and PYY. Sitagliptin affected the exposure to GSK-1292263 (50% increase) but GSK-1292263 did not affect sitagliptin exposure. The data support further evaluation of GSK-1292263 for the treatment of type 2 diabetes (Source: Nunez, D.J. et al. Diabetes [70th Annu Meet Sci Sess Am Diabetes Assoc (ADA) (June 25-29, Orlando) 2010] 2010, 59(Suppl. 1): Abst 80-OR).

WO 2008070692

http://www.google.com.au/patents/WO2008070692A2?cl=en

Example 169: 5-[({1 -[3-(1 -Methylethyl)-1,2,4-oxadiazol-5-yl]-4- piperidinyl}methyl)oxy]-2-[4-(methylsulfonyl)phenyl]pyridine hydrochloride

Step 1 : A mixture of 6-bromo-3-pyridinol (7 g, 40 mmol), [4-(methylsulfonyl)phenyl]boronic acid (8 g, 40 mmol), 2M Na₂CO₃ (30 ml_), PdCI₂(PPh₃)₂ (1 g) and DME (60 ml.) under N₂ was heated at 80 ⁰C overnight. The reaction was allowed to cool to room temperature and was diluted with EtOAc and water. The resulting precipitate was filtered off and the aqueous layer was extracted with EtOAc. The combined organic extracts were dried over MgSO4, filtered and concentrated. The aqueous phase was also concentrated. Each of the residues was recrystallized from MeOH. The solid material from the organic phase recrystallization and the mother liquors from both aqueous and organic recrystallizations were combined, concentrated and purified by chromatography on a silica gel column using 0 to 10% MeOH/CH₂CI₂ to give 6-[4-(methylsulfonyl)phenyl]-3-pyridinol (2.9 g, 29%) as a tan solid. Step 2: Diisopropyl azodicarboxylate (0.175 ml_, 0.89 mmol) was added dropwise to a solution of 6-[4-(methylsulfonyl)phenyl]-3-pyridinol (150 mg, 0.59 mmol), {1-[3-(1- methylethyl)-1 ,2,4-oxadiazol-5-yl]-4-piperidinyl}methanol (prepared as in Example 20, Steps 1-3, 200 mg, 0.89 mmol), PPh₃ (233 mg, 0.89 mmol), and THF (10 ml.) at ambient temperature. The mixture was stirred at ambient temperature for 4 h. The mixture was concentrated, and the resulting crude was purified by reverse-phase preparative HPLC using a CH₃CN:H₂O gradient (10:90 to 100:0) with 0.05% TFA as a modifier, then taken up in CH₂CI₂ and free-based with saturated NaHCO₃ (aq) to give 5-[({1-[3-(1-methylethyl)-1 ,2,4-oxadiazol-5-yl]-4-piperidinyl}methyl)oxy]-2-[4- (methylsulfonyl)phenyl]pyridine (220 mg) as a white solid. Step 3: A mixture of the resulting white solid (50 mg, 0.1 1 mmol) in THF (3 ml.) was stirred at ambient temperature as 4Λ/ HCI in dioxane (28 μl_) was added dropwise. The resulting white precipitate was filtered, air-dried, then triturated with diethyl ether to give 35 mg (65%) of the title compound as a white solid. ¹H NMR (400 MHz, CDCI₃): δ 8.46 (d, 1 H, J = 0.7 Hz), 8.18 (bs, 2H), 8.05 (bs, 2H), 7.83 (bs, 1 H), 7.61- 7.45 (m, 1 H), 4.24 (d, 2H, J = 10.4 Hz), 4.00 (d, 2H, J = 0.6 Hz), 3.21-3.03 (m, 5H), 2.89 (m, 1 H), 2.15 (d, 1 H, J = 1.1 Hz), 1.96 (bs, 2H), 1.50 (bs, 2H), 1.28 (d, 6H, J = 6.9 Hz); LRMS (ESI), m/z 457 (M+H).

PATENT

http://www.google.co.ug/patents/US20120077812

Example 100

5-[({1-[3-(1-Methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}methyl)oxy]-2-[4-(methylsulfonyl)phenyl]pyridine[0480]

Step 1: A mixture of 2-methylpropanenitrile (100 g, 1.45 mol), hydroxylamine hydrochloride (111 g, 1.59 mol) and NaOH (64 g, 1.59 mol) in EtOH (2 L) and water (500 mL) was stirred at reflux overnight. The mixture was evaporated to dryness and extracted with dichloromethane. The organic extract was dried over Na₂SO₄and concentrated to afford the desired N-hydroxy-2-methylpropanimidamide (50 g, 34%).

Step 2: A solution of 4-piperidinemethanol (140 g, 1.22 mol) in CH₂Cl₂(1 L) was treated with a slurry of NaHCO₃(205 g, 2.44 mol) in water (1.4 L) at 0° C. The mixture was stirred at 0° C. for 15 min, and then charged with a solution of cyanogen bromide in CH₂Cl₂, (1.34 mol) at 0° C. The reaction mixture was stirred and allowed to warm to ambient temperature, and stirred overnight. The aqueous layer was separated and extracted with CH₂Cl₂. The combined organic extracts were dried over Na₂SO₄, filtered, and the filtrate was concentrated. The crude product was combined with other batches made similarly and purified by chromatography on a silica gel column to give 300 g of 4-(hydroxymethyl)-1-piperidinecarbonitrile. Step 3: A solution of 1N ZnCl₂in Et₂O (182 mL, 182 mmol) was added to a solution of 4-(hydroxymethyl)-1-piperidinecarbonitrile (21.3 g, 152 mmol) and N-hydroxy-2-methylpropanimidamide (18.6 g, 182 mmol) in EtOAc (50 mL) at ambient temperature. The reaction mixture was left at ambient temperature for 30 min, decanted, and was treated with concentrated HCl (45 mL) and ethanol 20 mL). The mixture was heated at reflux for 2 h. The mixture was evaporated to dryness, and the resulting residue was charged with water and the pH was adjusted to basic with K₂CO₃. The mixture was extracted with EtOAc and the material obtained was combined with 9 other batches prepared similarly and purified by silica gel chromatography to give 150 g of {1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}methanol.

Step 4: A solution of {1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}methanol (prepared as in Step 3, 174 g, 0.77 mol) and triethylamine (140 mL, 1.0 mol) in dichloromethane (1 L) at 5° C. was treated with a solution of methanesulfonyl chloride (69 mL, 0.89 mol) in dichloromethane (150 mL) over a 1 h period. The mixture was stirred at 5° C. for 30 min, and then was quenched by the addition of water (400 mL). The mixture was stirred for 30 min, and then the organic extract was washed with water (2×400 mL), dried (MgSO₄) and concentrated. The residue was treated with heptane (1 L), stirred for 3 h, and the resulting solid was collected by filtration (heptane wash) and air-dried to afford {1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}methyl methanesulfonate (219.7 g, 94%) as an off-white solid. ¹NMR (400 MHz, CDCl₃): δ 4.21-4.15 (m, 2H), 4.08 (d, 2H, J=6.6 Hz), 3.04 (m, 2H), 3.01 (s, 3H), 2.86 (septet, 1H, J=6.9 Hz), 2.05-1.93 (m, 1H), 1.88-1.81 (m, 2H), 1.43-1.31 (m, 2H), 1.26 (d, 6H, J=6.8 Hz); LRMS (ESI), m/z 304 (M+H).

Step 5: A mixture of 6-bromo-3-pyridinol (36 g, 207 mmol), [4-(methylsulfonyl)phenyl]boronic acid (50 g, 250 mmol), 2M Na₂CO₃(315 mL) and DME (500 mL) was degassed with N₂for 30 min, and then Pd(PPh₃)₄(12 g, 10 mmol) was added and the mixture was heated at 80° C. for 18 h. The reaction was allowed to cool to room temperature and was diluted with dichloromethane (500 mL) and water (500 mL) and stirred for 30 min. The reaction was filtered and the solids were rinsed with dichloromethane and the aqueous layer was extracted with dichloromethane. The combined organic extracts were extracted with 1N NaOH (2×600 mL), and then cooled to 5° C. and the pH was adjusted to ˜8 with 6N HCl. The resulting precipitate was collected by filtration (water wash) and air-dried to afford a yellow solid. This procedure was repeated and the solids were combined to provide (71.2 g, 68%) of 6-[4-(methylsulfonyl)phenyl]-3-pyridinol. ¹H NMR (400 MHz, DMSO-d₆): δ 10.27 (s, 1H), 8.25 (d, 1H, J=2.7 Hz), 8.21 (d, 2H, J=8.5 Hz), 8.00-7.90 (m, 3H), 7.27 (dd, 1H, J_a=8.7 Hz, J_b=2.8 Hz), 3.21 (s, 3H); LRMS (ESI), m/z 250 (M+H).

Step 6: A mixture of {1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}methyl methanesulfonate (82.3 g, 271 mmol), 6-[4-(methylsulfonyl)phenyl]-3-pyridinol (71.0 g, 285 mmol), powdered potassium carbonate (118 g, 855 mmol) and N,N-dimethylformamide (750 mL) was mechanically stirred and heated at 80° C. under nitrogen for 20 h. The reaction was cooled to ambient temperature, poured onto ice water (3 L) and allowed to stand for 1 h. The resulting solid was filtered, rinsed with water (2×500 mL) and air-dried. The solid was taken up in dichloromethane (300 mL) and methanol (500 mL). The dichloromethane was slowly removed via rotovap at 55° C. The methanol solution was allowed to stand at ambient temperature for 16 h. The resulting crystalline solid was filtered, rinsed with cold methanol and dried under vacuum at 60° C. for 18 h to afford the desired product (105.7 g, 84%) as a light tan solid. ¹H NMR (400 MHz, CDCl₃): δ 8.41 (d, 1H, J=2.8 Hz), 8.13 (d, 2H, J=8.6 Hz), 8.01 (d, 2H, J=8.6 Hz), 7.74 (d, 1H, J=8.7 Hz), 7.29 (dd, 1H, J_a=8.7 Hz, J_b=3.0 Hz), 4.24 (d, 2H, J=13.1 Hz), 3.95 (d, 2H, J=6.2 Hz), 3.17-3.04 (m, 5H), 2.94-2.84 (m, 1H), 2.11 (bs, 1H), 1.97 (d, 2H, J=12.6 Hz), 1.54-1.42 (m, 2H), 1.29 (d, 6H, J=7.0 Hz); LRMS (ESI), m/z 457 (M+H).

Alternative preparation: Step 1: 2-Bromo-5-[({1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}methyl)oxy]pyridine (220 mg, 29%) was prepared as a white solid from {1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}methanol (prepared as in Example 20, Steps 1-3, 348 mg, 2.0 mmol), 6-bromo-3-pyridinol (348 mg, 2.0 mmol) and Ph₃P (629 mg, 2.4 mmol) in THF (5 mL) followed by diisopropyl azodicarboxylate (0.51 mL, 2.6 mmol) in a manner similar to Example 1, Step 2. ¹H NMR (400 MHz, CDCl₃): δ 8.04 (s, 1H), 7.37 (d, 1H, J=8.8 Hz), 7.08 (d, 1H, J=8.8 Hz), 4.26-4.16 (m, 2H), 3.85 (d, 2H, J=6.2 Hz), 3.14-3.04 (m, 2H), 2.95-2.76 (m, 1H), 2.11-1.96 (m, 1H), 1.98-1.88 (m, 2H), 1.52-1.36 (m, 2H), 1.28 (d, 6H, J=6.9 Hz); LRMS (ESI), m/z 381/383 (M+H).

Step 2: 5-[({1-[3-(1-Methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}methyl)oxy]-2-[4-(methylsulfonyl)phenyl]pyridine (51 mg, 21%) was prepared from 2-bromo-5-[({1-[3-(1-methylethyl)-1,2,4-oxadiazol-5-yl]-4-piperidinyl}methyl)oxy]pyridine (220 mg, 0.52 mmol), [4-(methylsulfonyl)phenyl]boronic acid (105 mg, 0.52 mmol), 2M Na₂CO₃(5 mL), Pd(PPh₃)₄(50 mg, 0.04 mmol) and DME (5 mL) in a manner similar to Example 21, Step 3.

Paper

Development of Large-Scale Routes to Potent GPR119 Receptor Agonists

Org. Process Res. Dev., Article ASAP

DOI: 10.1021/acs.oprd.6b00157, http://pubs.acs.org/doi/abs/10.1021/acs.oprd.6b00157

Publication Date (Web): July 13, 2016

*E-mail: richard.t.matsuoka@gsk.com.

Abstract

///////////1292263, GSK-1292263, GSK-1292263A, GSK-263A, GSK1292263, GSK1292263A, GSK 1292263, GSK 1292263A, GSK 263A, GSK263A, 1032823-75-8

O=S(C1=CC=C(C2=CC=C(OCC3CCN(C4=NC(C(C)C)=NO4)CC3)C=N2)C=C1)(C)=O

Supporting Info

VELPATASVIR (GS-5816), GILEAD SCIENCES, велпатасвир, فالباتاسفير , 维帕他韦 ,

FDA 2016, Uncategorized Comments Off

Jul 302016

VELPATASVIR (GS-5816), GILEAD SCIENCES

CAS 1377049-84-7

Molecular Formula:	C₄₉H₅₄N₈O₈
Molecular Weight:	883.00186 g/mol

Hepatitis C virus NS 5 protein inhibitors

KEEP WATCHING AS I ADD MORE DATA, SYNTHESIS……………

Gilead Sciences, Inc. INNOVATOR

Elizabeth M. Bacon, Jeromy J. Cottell, Ashley Anne Katana, Darryl Kato, Evan S. Krygowski, John O. Link, James Taylor, Chinh Viet Tran, Martin Teresa Alejandra Trejo, Zheng-Yu Yang, Sheila Zipfel,

Elizabeth Bacon

Senior Research Associate II at Gilead Sciences

Methyl {(2S)-1-[(2S,5S)-2-(5-{2-[(2S,4S)-1-{(2R)-2- [(methoxycarbonyl)amino]-2-phenylacetyl}-4- (methoxymethyl)pyrrolidin-2-yl]-1 ,1 1 dihydroisochromeno[4′,3′:6,7]naphtho[1 ,2-d]imidazol-9-yl}-1 H-imidazol-2-yl)-5- methylpyrrolidin-1 -yl]-3-methyl-1 -oxobutan-2-yl}carbamate

methyl {(2S)-1-[(2S,5S)-2-(9-{2-[(2S,4S)-1-{(2R)-2-[(methoxycarbonyl)amino]-2-phenylacetyl}-4-(methoxymethyl)pyrrolidin-2-yl]-1H-imidazol-5-yl}-1,11-dihydroisochromeno[4′,3′:6,7]naphtho[1,2-d]imidazol-2-yl)-5-methylpyrrolidin-1-yl]-3-methyl-1-oxobutan-2-yl}carbamate

methyl {(2S)-1 – [(2S,5S)-2-(5-{2-[(2S,4S)-l- {(2R)-2-[(methoxycarbonyl)amino]-2-phenylacetyl} -4-(methoxymethyl) pyrrolidin-2-yl]-l,l 1 dihydroisochromeno [4′,3′:6,7]naphtho[l,2-d]imidazol-9-yl}-lH-imidazol-2-yl)- 5-methylpyrrolidin-l-yl]-3-methyl-l -oxobutan-2-yl}carbamate

Sheila Zipfel

Research Scientist I at Gilead Sciences

{(2S)-1-[(2S,5S)-2-(9-{2-[(2S,4S)-1-{(2R)-2-[(Méthoxycarbonyl)amino]-2-phénylacétyl}-4-(méthoxyméthyl)-2-pyrrolidinyl]-1H-imidazol-4-yl}-1,11-dihydroisochroméno[4′,3′:6,7]naphto[1,2-d]imidazol-2-yl)-5 -méthyl-1-pyrrolidinyl]-3-méthyl-1-oxo-2-butanyl}carbamate de méthyle

Carbamic acid, N-[(1R)-2-[(2S,4S)-2-[4-[1,11-dihydro-2-[(2S,5S)-1-[(2S)-2-[(methoxycarbonyl)amino]-3-methyl-1-oxobutyl]-5-methyl-2-pyrrolidinyl][2]benzopyrano[4′,3′:6,7]naphth[1,2-d]imidazol-9-yl]-1H- imidazol-2-yl]-4-(methoxymethyl)-1-pyrrolidinyl]-2-oxo-1-phenylethyl]-, methyl ester

Methyl {(2S)-1-[(2S,5S)-2-(9-{2-[(2S,4S)-1-{(2R)-2-[(methoxycarbonyl)amino]-2-phenylacetyl}-4-(methoxymethyl)pyrrolidin-2-yl]-1H-imidazol-4-yl}-1,11-dihydro[2]benzopyrano[4′,3′:6,7]naphtho[1,2-d]imidazol-2-yl)-5-methylpyrrolidin-1-yl]-3-methyl-1-oxobutan-2-yl}carbamate

Description	Pan-genotypic HCV NS5A inhibitor
Molecular Target	HCV NS5A protein
Mechanism of Action	HCV non-structural protein 5A inhibitor
Therapeutic Modality	Small molecule

Latest Stage of Development	Phase II
Standard Indication	Hepatitis C virus (HCV)
Indication Details	Treat HCV genotype 1 infection; Treat HCV infection

Gilead Sciences
Class Antivirals; Carbamates; Chromans; Imidazoles; Naphthols; Phenylacetates; Phosphoric acid esters; Pyrimidine nucleotides; Pyrrolidines; Small molecules
Mechanism of Action Hepatitis C virus NS 5 protein inhibitors

Registered Hepatitis C

Most Recent Events

14 Jul 2016 Registered for Hepatitis C in Canada (PO)
08 Jul 2016 Registered for Hepatitis C in Liechtenstein, Iceland, Norway, European Union (PO)
30 Jun 2016 Gilead Sciences plans a phase III trial for Hepatitis C (Combination therapy, Treatment-experienced) in Japan (PO (NCT02822794)

Darryl Kato works on a hepatitis treatment at Gilead Sciences Inc.’s lab

Velpatasvir, also known as GS-5816, is a potent and selective Hepatitis C virus NS5A inhibitor. GS-5816 has demonstrated pan-genotypic activity and a high barrier to resistance in HCV replicon assays. GS-5816 demonstrated pangenotypic antiviral activity in patients with genotype 1-4 HCV infection. It will be further evaluated in combination with other pangenotypic direct-acting antivirals to achieve the goal of developing a well-tolerated, highly effective treatment for all HCV genotypes.

WO 2013/075029. Compound I has the formula:

PAPER

Patent Highlights: Recently Approved HCV NS5a Drugs

David L. Hughes^*

Cidara Therapeutics, 6310 Nancy Ridge Dr., Suite 101, San Diego, California 92121, United States

Org. Process Res. Dev., Article ASAP

DOI: 10.1021/acs.oprd.6b00241, http://pubs.acs.org/doi/abs/10.1021/acs.oprd.6b00241

*E-mail: dhughes@cidara.com.

Abstract

Five inhibitors of the NS5a enzyme have been approved as part of oral regimens for the treatment of hepatitis C virus, including daclatasvir (Bristol-Myers Squibb), ledipasvir (Gilead Sciences), ombitasvir (AbbVie), elbasvir (Merck), and velpatasvir (Gilead Sciences). This article reviews worldwide patents and patent applications that have been published on synthetic routes and final forms for these five drugs.

PATENT

https://google.com/patents/WO2013075029A1?cl=en

Example NP

Methyl {(2S)-l-[(2S,5S)-2-(5-{2-[(2S,4S)-l-{(2R)-2-[(methoxycarbonyl)amino]-2-phenylacetyl}-4- (methoxymethyl)pyrrolidin-2-yl]-l,ll dihydroisochromeno [4′,3′:6,7]naphtho[l,2-d]imidazol-9- yl}-lH-imidazol-2-yl)-5-methylpyrrolidin-l-yl]-3-methyl-l-oxobutan-2-yl}carbamate

The synthesis of this compound was prepared according to the procedure of example LR-1 with the following modification. During the Suzuki coupling, (2S)-l-[(2S,5S)-2-(5-iodo-lH-imidazol- 2-yl)-5-methylpyrrolidin-l-yl]-2-[(l-meth^ was used in lieu of

(2S)-l -[(2S)-2-(5-bromo-lH-imidazol-2-yl)pyrrolidin-l-yl]-2-[(l-methoxyethenyl)amino]-3- methylbutan-l-one. The crade material was purified by preparative HPLC to provide methyl {(2S)-1 – [(2S,5S)-2-(5-{2-[(2S,4S)-l- {(2R)-2-[(methoxycarbonyl)amino]-2-phenylacetyl} -4-(methoxymethyl) pyrrolidin-2-yl]-l,l 1 dihydroisochromeno [4′,3′:6,7]naphtho[l,2-d]imidazol-9-yl}-lH-imidazol-2-yl)- 5-methylpyrrolidin-l-yl]-3-methyl-l -oxobutan-2-yl}carbamate as a white solid (17 mg, 0.019 mmol, 17%). ^lU NMR (400 MHz, cd₃od) δ 8.63 (s, 1H), 8.19 (d, 1H), 8.04 (m, 1H), 7.87 (m, 2H), 7.66 (m, 2H), 7.52 – 7.39 (m, 6H), 5.50 (m, 2H), 5.32 (s, 2H), 5.16 (m, 1H), 4.12 (m, 1H), 3.80 (m, 4H), 3.66 (s, 6H), 3.43 (m, 4H), 3.23 (s, 3H), 2.72-1.99 (m, 9H), 1.56 (d, 3H), 1.29 (m, 1H), 0.99 (d, 3H), 0.88 (d, 3H).

PATENT

US 20150361073 A1

Scheme 1

Compound (J)

Compound (I) H CO- Com pound (G)

^st alkylation: Conversion of Compound (I-a) to Compound (G-a)

Compound (I-a) (45 g, 1.0 equiv.), Compound (J-a) (26.7g, 1.03 equiv.) and potassium carbonate (20.7g, 1.5 equiv.) in dichloromethane (450 mL) were stirred at about 20 °C for approximately 3-4 hours. After the completion of the reaction, water (450 mL) was charged into the reactor and the mixture was stirred. Layers were separated, and the aqueous layer was extracted with dichloromethane (200 mL). The combined organic layers were washed with 2 wt% NaH₂PO4/10wt% NaCl solution (450 mL). The organic layer was then concentrated and the solvent was swapped from dichloromethane into tetrahydrofuran. A purified sample of Compound (G-a) has the following spectrum: ¾ NMR (400 MHz,

CDC1₃) δ 7.90-7.94 (m, 1H), 7.81-7.85 (m, 1H), 7.72 (s, 1H), 7.69 (s, 1H), 7.66 (s, 1H), 5.19-5.56 (2dd, 2H), 5.17 (s, 2H), 4.73 (t, 1H), 4.39-4.48 (m, 1H), 3.70-3.77 (m, 1H), 3.37-3.45 (m, 2H), 3.33-3.35 (d, 3H), 3.28-3.32 (m, 1H), 3.20-3.25 (dd, 1H), 2.92-2.96 (dt, 1H), 2.44-2.59 (m, 4H), 1.97-2.09 (m, 1H), 1.44 (d, 9H).

Alternative reagents and reaction conditions to those disclosed above may also be employed. For example, alternative starting material may be Compound (I) where X may be -CI, -Br, -OTs, -OS0₂Ph, -OS0₂Me, -OS0₂CF₃, -OS0₂R, , and -OP(0)(OR)₂ and Y may be -CI, -Br, -OTs, -OS0₂Ph, -OS0₂Me, -OS0₂CF₃, -OS0₂R, and -OP(0)(OR)₂. R may be alkyl, haloalkyl, or an optionally substituted aryl.

Various bases may also be employed, such as phosphate salts (including but not limited to KH₂P0₄, K₃P0₄, Na₂HP0₄, and Na₃P0₄) and carbonate salts (including but not limited to Na₂C0₃,Cs₂C0₃, and NaHC0₃). Where the starting material is Compound (J), KHC0₃ or preformed potassium, sodium, and cesium salts of Compound (J) may also be used.

Alternative solvents can include 2-methyltetrahydrofuran, tetrahydrofuran, isopropyl acetate, ethyl acetate, tert-butyl methyl ether, cyclopentyl methyl ether, dimethylformamide, acetone, MEK, and MIBK.

The reaction temperature may range from about 10 °C to about 60 °C.

” alkylation: Conversion of Compound (G-a) to Compound (B-a):

A solution of Compound (G-a) (prepared as described earlier starting from 45 g of Compound (I-a)) was mixed with Compound (H) (42.9g, 1.5 equiv.), and cesium carbonate (26. lg, 0.8 equiv.). The reaction mixture was stirred at about 40-45 °C until reaction was complete and then cooled to about 20 °C. Water (450 mL) and ethyl acetate (225 mL) were added and the mixture was agitated. Layers were separated, and the aqueous layer was extracted with ethyl acetate (150 mL). Combined organic phase was concentrated and solvent was swapped to toluene. A purified sample of Compound (B-a) has the following spectrum: ¾ NMR (400 MHz, CDC1₃) 57.90-7.93 (m, 1H), 7.81-7.83 (m, 1H), 7.73 (s, 1H), 7.63-7.64 (d, 1H), 7.59-7.60 (d, 1H), 5.52-5.63 (m, 1H), 5.30-5.43 (q, 1H), 5.13-5.23 (s+m, 3H), 4.56-4.64 (m, 2H), 4.39-4.48 (m, 1H), 4.20-4.27 (m, 1H), 3.62-3.79 (m, 2H), 3.66 (s, 2H), 3.36-3.45 (m, 2H), 3.34-3.35 (d, 3H), 3.07-3.25 (m, 3H), 2.59-2.37 (m, 5H), 1.97-2.16 (m, 3H), 1.60 (s, 3H), 1.38-1.45 (m, 12H), 0.91-1.03 (m, 6H).

Alternative reagents and reaction conditions to those disclosed above may also be employed. For example, alternative starting material may include Compound (G) where Y may be -CI, -Br, -OTs, -OS0₂Ph, -OS0₂Me, -OS0₂CF₃, -OS0₂R, , or -OP(0)(OR)₂. where R is alkyl, aryl, or substituted aryl. In some embodiments, the substituted aryl may be an aryl having one or more substituents, such as alkyl, alkoxy, hydroxyl, nitro, halogen, and others as discussed above.

Various bases may be employed. Non-limiting examples can include phosphate salts (including but not limited to KH₂P0₄, K₃P0₄, Na₂HP0₄, and Na₃P0₄) and carbonate salts (including but not limited to K₂C0₃ or Na₂C0₃). If Compound (H) is used as the starting material, Li₂C0₃ or preformed potassium, sodium, and cesium salt of Compound (H) may be employed.

Alternative solvents may include 2-methyltetrahydrofuran, dichloromethane, toluene, mixtures of THF/Toluene, isopropyl acetate, ethyl acetate, l-methyl-2-pyrrolidinone, Ν,Ν-dimethylacetamide, acetone, MEK,and MIBK. An alternative additive may be

potassium iodide, and the reaction temperature may range from about 40 °C to about 60 °C or about 40 °C to about 50 °C.

A toluene solution of Compound (B-a) (604 g solution from 45 g of Compound (I-a)) was charged to a reaction vessel containing ammonium acetate (185.2 g) and isopropanol (91.0 g). The contents of the reactor were agitated at about 90 °C until the reaction was complete (about 16 to 24 hours). The reaction mixture was cooled to about 45 °C, and then allowed to settle for layer separation. Water (226 g) was added to the organic phase, and the resulting mixture was separated at about 30 °C. Methanol (274 g), Celite (26.9 g) and an aqueous solution of sodium hydroxide (67.5 g, 50%) and sodium chloride (54.0 g) in water (608 g) were added to the organic phase, and the resulting mixture was agitated for a minimum of 30 minutes. The mixture was then filtered through Celite and rinsed forward with a mixture of toluene (250 g) and isopropanol (1 1 g). The biphasic filtrate was separated and water (223 g) was added to the organic phase, and the resulting mixture was agitated at about 30 °C for at least 15 minutes. The mixture was filtered through Celite and rinsed forward with toluene (91 g). The organic layer was concentrated by vacuum distillation to 355 g and was added over 30 minutes to another reactor containing w-heptane (578 g). The resulting slurry is filtered, with the wetcake was washed with w-heptane (450 mL) and dried in a vacuum oven to afford Compound (C-a). A purified sample of Compound (C-a) has the following spectrum: *H NMR (400 MHz, CDC1₃) δ 12.27-11.60 (m, 1 H), 1 1.18-10.69 (m, 1 H), 7.83 – 7.44 (m, 4 H), 7.36 (d, J = 7.9 Hz, 1 H), 7.28 – 7.05 (m, 1 H), 5.65 – 5.25 (m, 1H), 5.25 – 4.83 (m, 4 H), 4.34 – 4.03 (m, 2 H), 3.93 – 3.63 (m, 4 H), 3.52 (s, 1 H), 3.35 (d, J = 2.4 Hz, 4 H), 3.19 – 2.94 (m, 4 H), 2.88 (dd, J = 12.0, 7.9 Hz, 3 H), 2.66 – 1.85 (m, 5 H), 1.79 (s, 5 H), 1.37 – 1.12 (m, 6H), 1.04-0.98 (m, 6 H), 0.82 (t, J = 7.7 Hz, 2 H).

Alternative reagents and reaction conditions to those disclosed above may also be employed. For example, alternative reagents, in lieu of ammonium acetate, can include hexamethyldisilazane, ammonia, ammonium formate, ammonium propionate, ammonium hexanoate, and ammonium octanoate. Various solvents, such as toluene, xylene, an alcohol

(including but not limited to isopropanol, 1-propanol, 1-butanol, 2-butanol, 2-methoxyethanol, and glycols, such as ethylene glycol and propylene glycol) may be employed. Alternative catalyst/additives may include magnesium stearate, acetic acid, propionic acid, and acetic anhydride. The reaction temperature may range from about 60 °C to about 110 °C or about 85 °C to about 95 °C.

Preparation of Compound (D-a) using DDQ as oxidant:

A solution of Compound (C-a) (255.84 g) in 2-methyltetrahydrofuran (1535 mL) was cooled to about 0 °C and acetic acid (0.92 mL) was added. To this mixture was added a solution of DDQ (76.98 g) in 2-methyltetrahydrofuran (385 mL) over about 30 minutes. Upon reaction completion, a 10 wt% aqueous potassium hydroxide solution (1275 mL) was added over about 30 minutes and the mixture was warmed to about 20 °C. Celite (101.5 g) was added and the slurry was filtered through Celite (50.0 g) and the filter cake was rinsed with 2-methyltetrahydrofuran (765 mL). The phases of the filtrate were separated. The organic phase was washed successively aqueous potassium hydroxide solution (1020 mL, 10 wt%), aqueous sodium bisulfite solution (1020 mL, 10 wt%), aqueous sodium bicarbonate solution (1020 mL, 5 wt%) and aqueous sodium chloride solution (1020 mL, 5 wt%). The organic phase was then concentrated to a volume of about 650 mL. Cyclopentyl methyl ether (1530 mL) was added and the resulting solution was concentrated to a volume of about 710 mL. The temperature was adjusted to about 40 °C and Compound (D-a) seed (1.0 g) was added. The mixture was agitated until a slurry forms, then methyl tert-butyl ether (2300 mL) was added over about 3 hours. The slurry was cooled to about 20 °C over about 2 hours and filtered. The filter cake was rinsed with methyl tert-butyl ether (1275 mL) and dried in a vacuum oven at about 40 °C to provide Compound (D-a). A purified sample of Compound (D-a) has the following spectrum: ¾ NMR (400 MHz, CDC1₃) δ 13.05-10.50 (comp m, 2H), 8.65-6.95 (comp m, 8H), 5.50-5.35 (m, 2H), 5.25^1.60 (comp m, 3H), 4.35-4.20 (m, 1H), 4.00-3.65 (comp m, 4H), 3.60-3.45 (m, 1H), 3.45-3.25 (comp m, 4H), 3.25-3.00 (comp m, 2H), 2.95-1.65 (comp m, 6H), 1.47 (br s, 9H), 1.40-1.25 (comp m, 2H), 1.20-0.70 (comp m, 9H).

Alternative Preparation of Compound (D-a) using Mn02 as oxidant:

A mixture of Compound (C-a) (50.0 g), manganese (IV) oxide (152.8 g) and dichloromethane (500 mL) is stirred at about 20 °C. Upon completion of the reaction, Celite (15 g) was added. The resulting slurry was filtered through Celite (20 g) and the filter cake was rinsed with dichloromethane (500 mL). The filtrate was concentrated and solvent exchanged into cyclopentyl methyl ether (250 mL). The resulting solution was warmed to about 60 °C and treated with an aqueous potassium hydroxide solution (250 mL, 10wt%). The biphasic mixture is stirred at about 45 °C for about 12 hours. The phases are then separated and the organic phase is concentrated to a volume of about 150 mL. The concentrate is filtered, seeded with Compound (D-a) seed and agitated at about 40 °C to obtain a slurry. Methyl tert-butyl ether (450 mL) was added to the slurry over 30 minutes and the resulting mixture was cooled to about 20 °C. The precipitated solid was filtered, rinsed with methyl tert-butyl ether (250 mL) and dried in a vacuum oven at about 40 °C to obtain Compound (D-a).

Alternative Preparation of Compound (D-a) through catalytic dehydrogenation

A mixture of Compound (C-a) (2.5 g, 2.7 mmol, 1 equiv), 5% Pd/Al₂0₃ (2.5 g) and 1-propanol (25 mL, degassed) was stirred at reflux under inert environment for about 5.5 hours. The reaction mixture was then cooled to ambient temperature and filtered through Celite, and the residue rinsed with 1-propanol (2 x 5 mL) to obtain a solution of Compound (D-a).

Alternative reagents and reaction conditions to those disclosed above may also be employed. For example, in a reaction scheme employing stoichiometric oxidants, alternative oxidants may include manganese(IV) oxide, copper(II) acetate, copper(II) trifluoroacetate, copper(II) chloride, copper(II) bromide, bromine (Br₂), iodine (I₂), N-chlorosuccinimide, N-bromosuccinimide, N-iodosuccinimide, 1 ,4-benzoquinone, tetrachloro-l,4-benzoquinone (chloranil), eerie ammonium nitrate, hydrogen peroxide, tert-butyl hydroperoxide, άϊ-tert-butyl peroxide, benzoyl peroxide, oxygen ((¾), sodium hypochlorite, sodium hypobromite, tert-butyl hypochlorite, Oxone, diacetoxyiodobenzene, and bis(trifluoroacetoxy)iodobenzene. Various additives may be employed, and non-limiting examples may be carbonate bases (e.g., potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate, and the like), amines (e.g., triethylamine, diisopropylethylamine and the like), and acids (e.g., trifluoroacetic acid, trichloroacetic acid, benzoic acid, hydrochloric acid, sulfuric acid, phosphoric acid, ara-toluenesulfonic acid, methanesulfonic acid), sodium acetate, potassium acetate, and the like). The reaction temperature may range from about -10°C to 80 °C. The reaction may take place in solvents, such as halogenated solvents (e.g., dichloromethane, 1,2-dichloroethane, etc.), aromatic solvents (e.g., toluene, xylenes, etc.), ethereal solvents (tetrahydrofuran, 1,4-dioxane, cyclopentyl methyl ether, 1 ,2-dimethoxyethane, diglyme, triglyme, etc.), alcoholic solvents (e.g., methanol, ethanol, w-propanol, isopropanol, n-butanol, tert-butanol, tert-amyl alcohol, ethylene glycol, propylene glycol, etc.), ester solvents (e.g., ethyl acetate, isopropyl acetate, tert-butyl acetate, etc.), ketone solvents (e.g., acetone, 2-butanone, 4-methyl-2-pentanone, etc.), polar aprotic solvents (e.g., acetonitrile, Ν,Ν-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidinone, pyridine, dimethyl sulfoxide, etc.), amine solvents (e.g., triethylamine, morpholine, etc.), acetic acid, and water.

In reaction schemes employing catalytic oxidants, alternative catalysts may include palladium catalysts (e.g., palladium(II) acetate, palladium(II) trifluoroacetate, palladium(II) chloride, palladium(II) bromide, palladium(II) iodide, palladium(II) benzoate, palladium(II) sulfate, tetrakis(triphenylphosphine)palladium(0), tris(dibenzylideneacetone)dipalladium(0), bis(tri-iert-butylphosphine)palladium(0), bis(triphenylphosphine)palladium(II) chloride, bis(acetonitrile)palladium(II) chloride, bis(benzonitrile)palladium(II) chloride, palladium on carbon, palladium on alumina, palladium on hydroxyapatite, palladium on calcium carbonate, palladium on barium sulfate, palladium(II) hydroxide on carbon), platinum catalysts (e.g., platinum on carbon, platinum(IV) oxide, chloroplatinic acid, potassium chloroplatinate), rhodium catalysts (e.g., rhodium on carbon, rhodium on alumina,

bis(styrene)bis(triphenylphosphine)rhodium(0)), ruthenium catalysts (e.g., ruthenium(II) salen, dichloro(para-cymene)ruthenium(II) dimer), iridium catalysts (e.g., iridium(III) chloride, (l,5-cyclooctadiene)diiridium(I) dichloride, bis(l,5-cyclooctadiene)iridium(I) tetrafluoroborate, bis(triphenylphosphine)(l,5-cyclooctadiene)iridium(I) carbonyl chloride, bis(triphenylphosphine)(l,5-cyclooctadiene)iridium(I) tetrafluoroborate), copper catalysts (e.g., copper(I) chloride, copper(II) chloride, copper(I) bromide, copper(II) bromide, copper(I) iodide, copper(II) iodide, copper(II) acetate, copper(II) trifluoroacetate, copper(I) trifluoromethanesulfonate, copper(II) trifluoromethanesulfonate, copper(II) sulfate), iron catalysts (e.g., iron(II) sulfate, iron(II) chloride, iron(III) chloride), vanadium catalysts (e.g., dichloro(ethoxy)oxovanadium, dichloro(isopropoxy)oxovanadium), manganese catalysts (e.g., manganese(rV) oxide, manganese(III) (salen) chloride), cobalt catalysts (e.g., cobalt(II) acetate, cobalt(II) chloride, cobalt(II) salen), indium(III) chloride, silver(I) oxide, sodium tungstate, quinone catalysts (e.g., 2,3-dichloro-5,6-dicyano-l,4-benzoquinone, 1,4-benzoquinone, and tetrachloro-l,4-benzoquinone (chloranil)).

Alternative co-oxidants can include, but are not limited to, sodium nitrite, copper(II) acetate, sodium persulfate, potassium persulfate, ammonium persulfate, sodium perborate, nitrobenzenesulfonate, 2,2,6,6-tetramethylpiperidine-l-oxyl (TEMPO), pyridine-N-oxide, hydrogen peroxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, benzoyl peroxide, oxygen (0₂), sodium hypochlorite, sodium hypobromite, tert-butyl hypochlorite, oxone, diacetoxyiodobenzene, and bis(trifluoroacetoxy)iodobenzene.

Varoius hydrogen acceptors may be employed. Non-limiting examples can include unsaturated hydrocarbons (e.g., tert-butylethylene, tert-butyl acetylene, 2-hexyne, cyclohexene, and the like), acrylate esters (e.g., methyl acrylate, ethyl acrylate, isopropyl acrylate, tert-butyl acrylate, and the like), maleate esters (e.g., dimethyl maleate, diethyl maleate, diisopropyl maleate, dibutyl maleate, and the like), fumarate esters (e.g., dimethyl fumarate, diethyl fumarate, diisopropyl fumarate, dibutyl fumarate, and the like), and quinones (e.g. chloranil, 1 ,4-benzoquinone, etc.).

Alternative additives may be employed, such as carbonate bases (e.g., potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate, etc.), amine bases (e.g., triethylamine, diisopropylethylamine, etc.), phosphines (e.g., triphenylphosphine, tri(ort zotolyl)phosphine, tricyclohexylphosphine, tri-w-butylphosphine, tri-tert-butylphosphine, etc.), acids (e.g., trifluoroacetic acid, trichloroacetic acid, benzoic acid, hydrochloric acid, sulfuric acid, phosphoric acid, ara-toluenesulfonic acid, methanesulfonic acid, etc.), sodium acetate, N-hydroxyphthalimide, salen, 2,2 ‘-bipyri dine, 9,10-phenanthroline, and quinine.

The reaction can proceed at temperatures ranging from about 10 °C to about 120 °C. Various solvents can be employed, including but not limited to halogenated solvents (e.g., dichloromethane, 1,2-dichloroethane, and the like), aromatic solvents (e.g., toluene, xylenes, and the like), ethereal solvents (tetrahydrofuran, 1,4-dioxane, cyclopentyl methyl ether, 1,2-dimethoxyethane, diglyme, triglyme, and the like), alcoholic solvents (e.g., methanol, ethanol, w-propanol, isopropanol, w-butanol, tert-butanol, tert-amyl alcohol, ethylene glycol, propylene glyco, and the like), ester solvents (e.g., ethyl acetate, isopropyl acetate, tert-butyl acetate, and the like), ketone solvents (e.g., acetone, 2-butanone, 4-methyl-2-pentanone, and the like), polar aprotic solvents (e.g., acetonitrile, Ν,Ν-dimethylformamide, Ν,Ν-dimethylacetamide, N-methyl-2-pyrrolidinone, pyridine, dimethyl sulfoxide, and the like), amine solvents (e.g., triethylamine, morpholine, and the like), acetic acid, and water.

Acetyl chloride (135 mL, 5 equiv.) was added slowly to methanol (750 mL) under external cooling maintaining reaction temperature below 30 °C. The resulting methanolic hydrogen chloride solution was cooled to about 20 °C, and added slowly over about 1 hour to a solution of Compound (D-a) (300 g, 1 equiv.) in methanol (750 mL) held at about 60 °C, and rinsed forward with methanol (300 mL). The reaction mixture was agitated at about 60 °C until reaction was complete (about 1 hour), and then cooled to about 5 °C. The reaction mixture was adjusted to pH 7-8 by addition of sodium methoxide (25 wt. % solution in methanol, 370 mL) over about 20 minutes while maintaining reaction temperature below about 20 °C. Phosphoric acid (85 wt. %, 26 mL, 1 equiv.) and Celite (120 g) were added to the reaction mixture, which was then adjusted to about 20 °C, filtered, and the filter cake was rinsed with methanol (1050 mL). The combined filtrate was polish filtered and treated with phosphoric acid (85 wt. %, 104 mL, 4 equiv.). The mixture was was adjusted to about 60 °C, seeded with Compound (E-a) seed crystals (1.5 g), aged at about 60 °C for 4 hours and cooled slowly to about 20 °C over about 7.5 hours. The precipitated product was filtered, washed with methanol (2 x 600 mL), and dried in a vacuum oven at about 45 °C to provide

Compound (E-a). ^!H NMR (400 MHz, D₂0) δ 7.53-6.77 (comp m, 8H), 5.24-4.80 (comp m, 3H), 4.59-4.38 (comp m, 2H), 4.15-3.90 (m, 1H), 3.65-3.38 (comp m, 5H), 3.36-3.14 (comp m, 4H), 2.75 (s, 1H), 2.87-2.66 (m, 1H), 2.29-1.60 (comp m, 6H), 1.27 (d, 3H), 0.76 (m, 6H).

Alternative reagents and reaction conditions to those disclosed above may also be employed. Various deprotection agents are well known to those skilled in the art and include those disclosed in T.W. Greene & P.G.M. Wuts, Protective Groups in Organic Synthesis (4th edition) J. Wiley & Sons, 2007, hereby incorporated by reference in its entirety. For example, a wide range of acids may be used, including but not limited to phosphoric acid, trifluoroacetic acid, p-toluenesulfonic acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, 4-bromobenzenesulfonic acid, thionyl chloride,and trimethylsilyl chloride. A wide range of solvents may be employed, including but not limited to water, ethanol, acetonitrile, acetone, tetrahydrofuran, 1 ,4-dioxane, and toluene. Deprotection may proceed at temperatures ranging from about 20 °C to about 110 °C or from about 55 °C to about 65 °C.

A wide range of bases may be employed as a neutralization reagent. Non-limiting examples can include sodium phosphate dibasic, potassium phosphate dibasic, potassium bicarbonate, lithium hydroxide, sodium hydroxide, potassium hydroxide, triethylamine, N, N-diisopropylethylamine, and 4-methylmorpholine. Various solvents may be used for neutralization, such as water, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, acetone, acetonitrile, 2-butanone, 4-methyl-2-pentanone, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, ethyl acetate, isopropyl acetate, dichloromethane, and dichloroethane.

Neutralization may proceed at temperatures ranging from about -20 °C to about 60 °C or about 5 °C to about 15 °C.

Various crystallization reagents can be employed. Non-limiting examples may be hydrochloric acid, hydrobromic acid, sulfuric acid, ethanesulfonic acid, benzenesulfonic acid, 4-bromobenzenesulfonic acid, oxalic acid, and glucuronic acid. Solvents for crystallization can include, but is not limited to, water, ethanol, 1-propanol, 2-propanol, and acetonitrile. Crystallization may proceed at temperatures ranging from about -20 °C to about 100 °C.

Free-Basing of Compound (E-a) to Prepare Compound (E)

ompound (E-a) OCH, H3CO- Compound (E)

Compound (E-a) (10.0 g, 10.1 mmol) was dissolved in water (100 g) and then dichloromethane (132 g) and 28% ammonium hydroxide (7.2 g) were added sequentially. The biphasic mixture was stirred for 45 minutes. Celite (2.2 g) was added, the mixture was filtered through a bed of additional Celite (5.1 g), and the phases were then separated. The lower organic phase was washed with water (50 g), filtered, and then concentrated by rotary evaporation to produce Compound (E). ‘H NMR (400 MHz, CD₃OD) δ 8.35-7.17 (m, 8H), 5.6^1.68 (m, 3H), 4.41-3.96 (m, 2H), 3.96-3.72 (br s, 1H), 3.74-3.48 (m, 2H), 3.42 (d, 2H), 3.33 (s, 3H), 3.28 (s, 1H), 3.19-3.01 (m, 1H), 3.00-2.79 (m, 1H), 2.69-1.82 (m, 6H), 1.80-1.45 (m, 3H), 1.21-0.73 (m, 8H).

Alternative reagents and reaction conditions to those disclosed above may also be employed. For example, tris-hydrochloride salts of Compound (E) may be used. Various bases may be employed, such as sodium carbonate, potassium carbonate, sodium hydroxide, and potassium hydroxide. Various solvents, such as 2-methyltetrahydrofuran and ethyl acetate, may be employed. The temperature may range from about 15 °C to about 25 °C.

Alternative Free-Basing of Compound (E-b) to Prepare Compound (E)

Compound (E-b) (15.2 g) was dissolved in water (100 g) and then dichloromethane

(132 g) and 28% ammonium hydroxide (7.4 g) were added sequentially. The biphasic mixture was stirred for about 45 minutes. Celite (2.1 g) was added, the mixture was filtered through a bed of additional Celite (5.2 g), and the phases were then separated. The lower organic phase was washed with water (50 g), filtered, and then concentrated by rotary evaporation to produce Compound (E). *H NMR (400 MHz, CD₃OD) δ 7.92-6.73 (m, 8H), 5.51-4.90 (m, 2H), 4.63-4.30 (m, 3H), 4.21-3.78 (m, 1H), 3.73-3.46 (m, 5H), 3.40-3.19 (m, 4H), 3.07-2.49 (m, 3H), 2.41-1.61 (m, 6H), 1.44-1.14 (m, 2H), 1.04-0.55 (m, 7H).

Salt Conversion of Compound (E-a) to Compound (E-b)

A solution of Compound (E-a) (10.0 g, 10.1 mmol), a solution of 37% HCI (10 g) in water (20 g), and acetonitrile (30 g)was warmed to about 50 °C and agitated for about lh. The solution was cooled to about 20 °C and acetonitrile (58 g) was charged to the reactor during which time a slurry formed. The slurry was stirred for about 21 h and then additional acetonitrile (39 g) was added. The slurry was cooled to about 0 °C, held for about 60 min and the solids were then isolated by filtration, rinsed with 7% (w/w) water in acetonitrile (22 g) previously cooled to about 5 °C. The wet cake was partially deliquored to afford

Compound (E-b). *H NMR (400 MHz, D₂0) δ 7.92-6.73 (m, 8H), 5.51^1.90 (m, 2H),

4.63-4.30 (m, 3H), 4.21-3.78 (m, 1H), 3.73-3.46 (m, 5H), 3.40-3.19 (m, 4H), 3.07-2.49 (m, 3H), 2.41-1.61 (m, 6H), 1.44-1.14 (m, 2H), 1.04-0.55 (m, 7H).

A flask was charged sequentially with 2-chloro-4,6-bis[3-(perfluorohexyl)propyloxy]-1,3,5-triazine (“CDMT”) (2.2 giv) and methanol (8.9 g) and the slurry was cooled to about 0 °C. To the mixture was added NMM (1.3 g) over about 5 minutes, maintaining an internal temperature of less than 20 °C. The solution was stirred for about 20 minutes to produce a solution of 4-(4,6-dimethoxy-l,3,5-triazin-2-yl)-4-methylmorpholinium chloride in methanol.

To a solution of Compound (E) (7.1 g) in dichloromethane (170 g) was added

Compound (Γ) (2.8 g). The solution of 4-(4,6-dimethoxy-l,3,5-triazin-2-yl)-4-methylmorpholinium chloride in methanol was added over 2 minutes followed by a rinse of methanol (1.1 g). After about 2.5 h, the completed reaction solution was washed sequentially with aqueous 10% potassium bicarbonate solution (40 mL), 3% hydrochloric acid (40 mL), and aqueous 10% potassium bicarbonate solution (40 mL). The lower organic phase was washed with water (40 mL), filtered, and then concentrated by rotary evaporation to produce Compound (A). ¾ NMR (400 MHz, CD₃OD) δ 8.56-6.67 (m, 13H), 5.76^1.94 (m, 4H), 4.86-4.67 (m, 1H), 4.47-3.98 (m, 1H), 3.98-2.72 (m, 15H), 2.74-1.77 (m, 7H), 1.77-1.40 (m, 2H), 1.39-0.53 (m, 8H).

Alternative reagents and reaction conditions to those disclosed above may also be employed. For example, tris-phosphate salts or tris-hydrochloride salts of Compound (G) may be used as alternative starting material. The reaction may take place at a temperature range of from about 10 °C to about 20 °C. Alternative coupling agents include, but are not limited to, EDC/HOBt, HATU, HBTU, TBTU, BOP, PyClOP, PyBOP, DCC/HOBt, COMU, EDCLOxyma, T3P, and 4-(4,6-dimethoxy-l,3,5-triazin-2-yl)-4-methylmorpholinium tetrafluoroborate. An alternative bases that may be employed can be diisopropylethylamine. The reaction may proceed in DMF and at temperatures ranging from about -20 °C to about 30 °C.

Salt Formation and Crystallization of Compound (A)

Crystallization of Compound (A-a)

A flask was charged with Compound (A) (10 g) and ethanol (125 mL) and was then warmed to about 45 °C. Concentrated hydrochloric acid (2.3 mL) was added followed by Compound (A-a) seed crystals (5 mg). The mixture was cooled to about 20 °C over about 5 h and held for about an additional 1 1 h. The solids were isolated by filtration, washed with ethanol (2 x 20 mL), and deliquored to produce Compound (A-a). ^!H NMR (400 MHz, CD₃OD) δ 8.94-7.22 (m, 14H), 5.78-5.1 1 (m, 5H), 4.53-4.04 (m, 1H), 3.99-3.57 (m, 10H), 3.57-3.41 (m, 2H), 2.99-2.24 (m, 5H), 2.24-1.85 (m, 3H), 1.80-1.50 (m, 2H), 1.39-0.73 (m, 8H).

Alternative Crystallization of Compound (A-b)

A reaction vessel was charged with Compound (A) (25.0 g) followed by ethanol (125 mL) and 10% H₃PO₄ (250 mL). The solution was seeded with Compound (A-b) (100 mg) and stirred for about 17.5 h. The solids were isolated by filtration, washed with ethanol (2 x 5 mL), deliquored, and dried in a vacuum oven to produce Compound (A-b). ^JH NMR (400 MHz, D₂0) δ 7.76-6.48 (m, 13H), 5.53^1.90 (m, 3H), 4.60-4.32 (m, 2H), 4.29-3.76 (m, 1H), 3.70-2.75 (m, 14H), 2.66-1.51 (m, 8H), 1.51-1.09 (m, 3H), 1.05-0.45 (m, 7H).

Alternative reagents and reaction conditions to those disclosed above may also be employed. For example, alternative acids may be hydrochloric acid, hydrobromic acid, L-tartaric acid. Various solvents may be employed, such as methanol, ethanol, water, and isopropanol. The reaction may proceed at temperatures ranging from about 5 °C to about 60 °C.

Free-Basing of Compound (A)

Free-Basing of Compound (A-a) to Prepare Compound (A)

A reaction vessel was charged with Compound (A-a) (18.2 g) followed by ethyl acetate (188 g) and 10% potassium bicarbonate (188 g) and the mixture was stirred for about 25 minutes. The phases were separated and the upper organic phase was then washed with water (188 mL). The resulting organic solution was concentrated, ethanol (188 g) was added, and the solution was evaporated to produce a concentrate (75 g). The resulting concentrate added into water (376 g) to produce a slurry. The solids were isolated by filtration, washed with water (38 g), de liquored and dried in a vacuum oven at about 50 °C to produce

Compound (A).

Alternative Free-Basing of Compound (A-b) to Prepare Compound (A)

om poun –

A reaction vessel was charged with Compound (A-b) (3.0 g) followed by EtOAc (15 mL) and 10% KHCO₃ (15 mL) and agitation was initiated. After about 5 h, the phases were separated and the organic phase was washed with water (15 mL) and then concentrated by rotary evaporation under vacuum. The residue was taken up in EtOH (4.5 mL) and then added to water (30 mL) to produce a slurry. After about 15 min, the solids were isolated by filtration rinsing forward water (3 x 3 mL). The solids were dried at about 50 to 60 °C vacuum oven for about 15 h to produce Compound (A).

PATENT

US 2015/0361085

https://patentscope.wipo.int/search/en/detail.jsf?docId=US153621930&redirectedID=true

Compound I Form I

An additional stable form screen was performed using the same procedure as described above but included a crystalline intermediate (Compound II shown below) as seeds.

Compound II can be synthesized according to the methods described in WO 2013/075029 or U.S. Provisional Application No. 62/010,813. Needle-like particles were formed in butyronitrile, propionitrile, MEK/toluene, MEK/IPE and 2-pentanone/toluene. XRPD patterns of the wet solids were mostly consistent with each other with minor shifting in the peaks. The new form is named Compound I Form I, which is believed to be isostructural channel solvates with the respective solvents. After air drying all solids afforded amorphous XRPD patterns.

Another stable form screen was performed using carbon (Darco G-60) treated Compound I, solvents, antisolvent (diisopropyl ether (IPE)), and seeds of Compound I Form I. This screen afforded crystalline solids from additional solvents as summarized in Table 1. The XRPD patterns of all of these solvates are consistent with Form I. The solvates were observed to convert to amorphous solids after drying. The XRPD patterns of Compound I were obtained in the experimental setting as follows: 45 kV, 40 mA, Kα1=1.5406 Å, scan range 2-40°, step size 0.0167°, counting time: 15.875 s.

[TABLE-US-00002]

TABLE 1

Stable form screen of carbon treated Compound I

Solvents	PLM	Comments

Water	Amorphous	Slurry
Water/EtOH	Amorphous	Sticky phase coating
ACN/IPE	Birefringent	Slurry of needles
MeOH/IPE	Solution	Seeds dissolved
EtOH/IPE	Solution	Seeds dissolved
Acetone/IPE	Birefringent	Thick slurry of
		needles
IPA/IPE	Amorphous	Sticky coating
MEK/IPE	Birefringent	Thick slurry of
		needles
MIBK/IPE	Birefringent	White paste
DCM/IPE	Birefringent	Thick slurry of small
		needles
THF/IPE	Solution	Seeds dissolved
2-MeTHF/IPE	Amorphous	slurry
EtOAc/IPE	Birefringent	Thick slurry of
		needles
IPAc/IPE	Amorphous	slurry
Toluene	Amorphous	Sticky coating

The crystallinity of Compound I Form I can be improved by using a butyronitrile/butyl ether (BN/BE) mixture according to the following procedure.

The crystallization experiment was started with 40 to 75 mg Compound I in 1.1 to 3.0 mL of a BN/BE in a ratio of 7:4 (anhydrous solvents). The sample was held at RT over P₂O₅for 23 days without agitation, and crystals formed in the solution. Afterwards, the liquid phase was replaced with butyl ether and the solids were obtained by centrifuge. These solids, corresponding to Compound I Form I, were used for the subsequent step as seed.

Purified Compound I (709.8 mg) was prepared from reflux of ethanol solution with Darco G-60 and was added to a new vial via a filter. While stirring, 7 mL of anhydrous butyronitrile (BN) was added. A clear orange solution was obtained. While stirring, 4 mL of anhydrous butyl ether (BE) was added slowly. To the solution was added 7.7 mg of Compound I Form I (from previous BN:BE crystallization experiment) as seed. The solution became cloudy and the seeds did not dissolve. The sample was stirred for ˜10 minutes before the agitation was stopped. The vial was capped and placed into a jar with some P₂O₅solids at room temperature. After 6 days, a thin layer of bright yellow precipitate was observed on the wall and the bottom of the vial. The liquid phase was withdrawn and 3 mL of anhydrous butyl ether was added. Solids were scraped down with a spatula from the vial. The suspension was heated to about 30° C. for over half hour period and was held for ˜1 hour before cooling to 20° C. at about 0.1° C./min (without agitation). The sample was stored in ajar with P₂O₅solids for 5 days. The sample was vacuum filtered using 0.22 μm nylon filter, washed with 2×200 μL of anhydrous butyl ether, and air dried under reduced pressure for about 5 minutes.

XRPD analysis of the sample showed good very sharp peaks as shown in FIG. 1. The XRPD analysis setting was as follows: 45 kV, 40 mA, Kα1=1.5406 Å, scan range 1-40°, step size 0.0167°, counting time: 36.83 s. The characteristic peaks of crystalline Compound I Form I include: 2.9, 3.6, 4.8, 5.2, 6.0° 2θ (FIG. 1). The XRPD pattern of Form I was successfully indexed, indicating that Form I is composed primarily of a single crystalline phase. Extremely large unit cell volume containing up to ˜60 API molecules in the unit cell was observed. The amorphous halo observed in the XRPD pattern could be a result of the size of the unit cell. Butyl ether stoichiometry could not be estimated. Two alternative indexing solutions were found: monoclinic and orthorhombic.

DSC and TGA data confirmed that Form I is a solvated form. DSC shows a broad endotherm with onset at 109° C. and small endotherm with onset at 177° C. (FIG. 2). TGA shows 22% weight loss below 150° C. (FIG. 3).

PATENT

CN 105294713

https://www.google.com/patents/CN105294713A?cl=en

https://patentimages.storage.googleapis.com/pdfs/2601c633c50937ffb780/CN105294713A.pdf

Example 12

Under nitrogen, was added l〇2g1 said, adding methylene burn 500 blood dissolved, 4mol / L fertilizer 1 1,4-dioxane SOOmL, football for 1 hour at room temperature, of the C (already burned: ethyl acetate 1: 1) point in the control board, the starting material spot disappeared, the reaction was stopped, the solvent was concentrated, was added (R & lt) -2- (methoxy several yl) -2-phenylacetic acid 29g, COMU60g, DMF blood 500, diisopropylethylamine 223M1,25 ° C reaction I h, ethyl acetate was added IL diluted, purified water is added IL painted twice, dried over anhydrous sulfate instrument, and concentrated, methanol was added SOOmL temperature 60 ° C dissolved, 250mL of purified water was slowly added dropwise, to precipitate a solid, the addition was completed, cooled to 50 ° C for 1 hour, cooled to room temperature, filtered, and concentrated to give Velpatasvir (GS-5816) product 90. 5g, 78. 2〇 yield / billion. H-NMR (400MHz, CDs isolated) 5 7. 94 – 7.67 (m, 4H), 7.59 of J = 9.1 Hz, 1H), 7. 52 (S, 1H), 7.48 – 7. 33 (m, 4H) , 7.11 of J = 18. 7Hz, 1H), 5.68 of J = 6.3Hz, 1H), 5.48 – 5.33 (m, 1H), 5.23 (dd, J = 24.1, 15.7Hz, 1H), 5.17 -5.03 (m, 3H), 4.22 (dd, J = 17.0, 9.6Hz, 1H), 4.16 – 4.01 (m, 1H), 3.91 (d, J = 24. 1 Hz, 1H), 3 83 -. 3. 68 (m, 1H), 3 68 -. 3. 59 (m, 3H), 3 59 -. 3. 49 (m, 3H), 3.38 (ddd, J = 15.9, 9.6, 5.7Hz, 2H), 3.28 – 3.14 (m, 5H), 3.10 (dd, J = 14.0, 8.2 Hz, 1H), 3.00 (dd, J = 17.8, 9.6Hz, 1H), 2.92 (dd, J = 14.5, 6.7 Hz, 1H), 2.73 – 2.41 (m, 2H), 2.40 – 2.11 (m, 2H), 2. 11 – 1.83 (m, 2H), 1.54 deduction J = 9. 7 Hz, 2H), 1.24 of J = 6.2Hz, 1H), 1.06 (t, J = 8.0 Hz, 1H), 0.99 of J = 6.8 Hz, 1H), 0. 94 (d, J = 6. 6Hz, 2H), 0. 85 (d, J = 6. 7Hz, 2H ).

Construction

Clip and foot notes

Velpatasvir only got its name last year and was previously known as GS-5816. That compound was only announced back in 2013 when Gilead showed the initial in vitrostudies on a handful of posters. [1] [2] Very little information is available on this follow-up compound. The following was pretty much the summary of their poster presentation.

To understand the medical significance of this study, Sofosbuvir is the best-in-class NS5B inhibitor from Gilead (see link for more information). [3] These inhibitors work the fastest when paired with a NS5A inhibitor like Daclatasvir or Ledipasvir (making up the Sofosbuvir+Ledipasvir = Harvoni combination) or the Viekira Pak combo. Disclosure: I am an employee of Bristol-Myers Squibb which produces Daclatasvir. However, HCV comprises of 7 different genotypes. Harvoni and Viekira Pak are approved against genotypes 1a, 1b. Harvoni is indicated for genotypes 4, 5, and 6. For the treatment of genotypes 2 and 3, sofosbuvir is generally combined with ribavirin or interferon which has notable side effects. While 70% of patients have genotype 1, for the remainder of patients with the other variants, they are still stuck with the more risky (and more expensive and longer) therapy.

I think this is the structure of GS-5816. It’s not yet published in any journal. [4]

For comparison, here is the structure of Ledipasvir, the first generation NS5A inhibitor used in Harvoni. Structurally speaking, they are pretty similar so it seems like GS-5816 is the product of good old fashioned medchem.

The clearest summary of the 4 Phase III trials can be found on Gilead’s website. [5]ASTRAL-1 was run on genotypes 1, 2, 4, 5, 6. [6] ASTRAL-2 focused on genotype 2. ASTRAL-3 focused on genotype 3. [7] ASTRAL-4 focused on HCV patients with Child-Pugh cirrhosis. [8] These patients previously had interferon treatment but had a poor response and are generally very sick.

I think that a few interesting things stand out. ASTRAL-1 occurred from July 2014 to December 2014 but upon a request from the FDA, ASTRAL-2 and 3 were started in September 2014-July 2015 in order to have an isolated study on genotypes 2 and 3. For a 24 week study that’s incredibly fast. As discussed elsewhere, clinical trials are often limited by the speed of patient enrollment and these studies can take years. [9] Here, they were able to find volunteers for a 1000 patient study within weeks. An interesting note about the clinical trial design, the ASTRAL-1 team knew that the historical cure rate was 85% and were able to correctly power the trial to get a statistically significant study on the first try. Also, deep sequencing was used to identify and stratify the HCV genotypes. In ASTRAL-1, 42% of the patients had NS5A resistance and 9% had NS5B resistance.

The market impact may be significant to Achillion which was a former partner of Gilead and a potential acquisition target. Achillion was working with Janssen on its own second generation NS5A inhibitor, odalasvir. This announcement may kill the market for a competing product as well as remove the acquisition hype.

How did Gilead come up with Velpatasvir? It really sounds like good solid science. Ledipasvir was developed to be a best-in-class NS5A inhibitor and it was recognized that it worked well with NS5B inhibitors. It was also understood that most of the NS5A inhibitors specific only towards certain N5SA genotypes and that there was a clear unmet need for patients with HCV genotypes 2 and 3. With the help of some computational modeling [10]Gilead developed assays for all of the HCV genotypes to screen for a pan-genotype NS5A inhibitor to follow up to their 2014 Ledipasvir trials and leveraging their strategic advantage in the HCV market, were able to quickly ramp up 4 major clinical trials to demonstrate the clinical efficacy of their next gen drug combination.

That’s really good science. Not long ago, Gilead stated that it was planning on eradicating HCV. This compound is a part of the Gilead license with Indian generic manufacturers but it seems like MSF is contesting that decision. [11] [12] With this drug Gilead is now another step closer towards that goal. [13]

Footnotes

[1] GS-5816, a Second-Generation HCV NS5A Inhibitor With Potent Antiviral Activity, Broad Genotypic Coverage, and a High Resistance Barrier

[2] Page on journal-of-hepatology.eu

[3] Christopher VanLang’s answer to How was Sovaldi (the drug now being marketed by Gilead), first discovered by Pharmasset?

[4] CAS # 1377049-84-7, Velpatasvir, GS 5816, Methyl [(2S)-1-[(2S,5S)-2-[9-[2-[(2S,4S)-1-[(2R)-2-[(methoxycarbonyl)amino]-2-phenylacetyl]-4-(methoxymethyl)pyrrolidin-2-yl]-1H-imidazol-5-yl]-1,11-dihydroisochromeno[4′,3′:6,7]naphtho[1,2-d]imidazol-2-yl]-5-methylpyrrolidin-1-yl]-3-methyl-1-oxobutan-2-yl]carbamate

[5] Page on gilead.com

[6] Sofosbuvir and Velpatasvir for HCV Genotype 1, 2, 4, 5, and 6 Infection — NEJM

[7] Sofosbuvir and Velpatasvir for HCV Genotype 2 and 3 Infection — NEJM

[8] Sofosbuvir and Velpatasvir for HCV in Patients with Decompensated Cirrhosis — NEJM

[9] Why do clinical trials for new drugs take several years? Remarkably, 72% of Americans are willing to be in them.

[10] Inhibition of hepatitis C virus NS5A by fluoro-olefin based γ-turn mimetics.

[11] Page on gilead.com

[12] MSF response to Gilead announcement on inclusion of hepatitis C drug GS-5816 in voluntary licence

[13] Gilead and Georgia to attempt Hep C eradication by Christopher VanLang on Making Drugs

09338-acsnews1-gileadcxd

SAVING LIVES

The Gilead team responsible for Harvoni: Front row, from left: John Link, Chris Yang, Rowchanak Pakdaman, Bob Scott, and Benjamin Graetz. Back row, from left: Erik Mogalian and Bruce Ross. Not pictured: Michael Sofia.

Credit: Gilead Sciences

Gilead’s Harvoni is a combination of two antiviral agents, sofosbuvir and ledipasvir. “In hepatitis C, the virus mutates so rapidly that to overcome resistance, we use a combination of drugs, and each one pulls their own weight in the process,” says John Link, who discovered ledipasvir.

Link says that the amount of interdisciplinary collaboration on the drug was unprecedented for the company. “Once ledipasvir was discovered, the process chemists were right there with us understanding the kinds of things we were doing, and medicinal chemists and process chemists worked on making material to scale for preclinical studies,” he says. “We all realized this was our moment to make a difference for patients with hepatitis C.”

Harvoni is the first once-a-day pill for treatment of chronic hepatitis C, and it has a cure rate in the U.S. of 94-99%. The drug is an alternative to injected interferon treatment, which has been associated with significant side effects.

“The high cure rates that we saw in our clinical trials are really amazing,” Link says. “Before we had these compounds, I had only hoped that we could equal something like interferon-type regimens in cure rates, without all the horrible side effects. To dramatically exceed them is important for patients.”

Harvoni patients can attest to the drug’s effectiveness. Mark Melancon, who had contracted hepatitis C 25 years ago, says that after taking Harvoni, he now has no trace of the virus in his body, and his liver is beginning to repair itself. “Four weeks into it, and the virus was gone. Not detectable,” he says. “To have this virus hanging over my head for 25 years and then it was just gone, I can’t explain the feeling. The people who worked hard on this medication, they need to know that I appreciate it.”

REFERENCES

https://www.eiseverywhere.com/file_uploads/c2a2b5664a374fe807c0b95bb546321d_JordanFeld.pdf

WO2013075029A1 *	Nov 16, 2012	May 23, 2013	Gilead Sciences, Inc.	Condensed imidazolylimidazoles as antiviral compounds

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Velpatasvir
Systematic (IUPAC) name

(2S)-2-{[hydroxy(methoxy)methylidene]amino}-1-[(2S,5S)-2-(17-{2-[(2S,4S)-1-[(2R)-2-{[hydroxy(methoxy)methylidene]amino}-2-phenylacetyl]-4-(methoxymethyl)pyrrolidin-2-yl]-1H-imidazol-5-yl}-21-oxa-5,7-diazapentacyclo[11.8.0.0³,¹¹.0⁴,⁸.0¹⁴,¹⁹]henicosa-1(13),2,4(8),6,9,11,14(19),15,17-nonaen-6-yl)-5-methylpyrrolidin-1-yl]-3-methylbutan-1-one
Identifiers
CAS Number	1377049-84-7
PubChem	CID 67683363
ChemSpider	34501056
UNII	KCU0C7RS7Z
Chemical data
Formula	C₄₉H₅₄N₈O₈
Molar mass	883.02 g·mol⁻¹

//////////////VELPATASVIR, GS-5816, GILEAD SCIENCES, Epclusa , FDA 2016, велпатасвир,فالباتاسفير , 维帕他韦 , велпатасвир, فالباتاسفير , 维帕他韦 , Elizabeth Bacon, Sheila Zipfel

UNII:KCU0C7RS7Z

C[C@H]1CC[C@H](N1C(=O)[C@H](C(C)C)NC(=O)OC)C2=NC3=C(N2)C=CC4=CC5=C(C=C43)OCC6=C5C=CC(=C6)C7=CN=C(N7)[C@@H]8C[C@@H](CN8C(=O)[C@@H](C9=CC=CC=C9)NC(=O)OC)COC

RNA virus antivirals (primarily J05, also S01AD and D06BB)

Hepatitis C

NS3/4A protease inhibitors (–previr)	Asunaprevir Boceprevir Faldaprevir^‡ Grazoprevir Paritaprevir Simeprevir Telaprevir

NS5A inhibitors (–asvir)	Daclatasvir Elbasvir Ledipasvir MK-3682 MK-8408 Odalasvir^† Ombitasvir Ravidasvir^† Samatasvir^† Velpatasvir

NS5B RNA polymerase inhibitors (–buvir)	Beclabuvir^† Dasabuvir Deleobuvir^§ Filibuvir^§ Setrobuvir^§ Sofosbuvir Radalbuvir^†

Combination drugs	Elbasvir/grazoprevir Ledipasvir/sofosbuvir Ombitasvir/paritaprevir/ritonavir Velpatasvir/sofosbuvir

Picornavirus

viral entry: Pleconaril^†

Anti-influenza agents

Umifenovir

neuraminidase inhibitors/release phase (Oseltamivir
Zanamivir
Peramivir, Laninamivir^†)

Multiple/general

Interferon	Interferon alfa 2b Peginterferon alfa-2a^#

Multiple/unknown	BCX4430 Favipiravir Moroxydine Ribavirin^#/Taribavirin^† Triazavirin

^#WHO-EM
^‡Withdrawn from market
Clinical trials:
- ^†Phase III
- ^§Never to phase III

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N-Butylpyrrolidinone as a dipolar aprotic solvent for organic synthesis

SYNTHESIS, Uncategorized Comments Off

Jul 292016

N-Butylpyrrolidinone as a dipolar aprotic solvent for organic synthesis

Green Chem., 2016, 18,3990-3996
DOI: 10.1039/C6GC00932H, Paper

James Sherwood, Helen L. Parker, Kristof Moonen, Thomas J. Farmer, Andrew J. Hunt
N-Butylpyrrolidinone (NBP) has been demonstrated as a suitable safer replacement solvent for N-Methylpyrrolidinone (NMP) in selected organic syntheses.

N-Butylpyrrolidinone as a dipolar aprotic solvent for organic synthesis

James Sherwood,^a Helen L. Parker,^a Kristof Moonen,^b Thomas J. Farmer^a and Andrew J. Hunt*^a

*Corresponding authors

^aGreen Chemistry Centre of Excellence, Department of Chemistry, University of York, UK
E-mail: andrew.hunt@york.ac.uk

^bEastman Chemical Company, Pantserschipstraat 207 – B-9000, Gent, Belgium

Green Chem., 2016,18, 3990-3996

http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C6GC00932H?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract
DOI: 10.1039/C6GC00932H

Dipolar aprotic solvents such as N-methylpyrrolidinone (or 1-methyl-2-pyrrolidone (NMP)) are under increasing pressure from environmental regulation. NMP is a known reproductive toxin and has been placed on the EU “Substances of Very High Concern” list. Accordingly there is an urgent need for non-toxic alternatives to the dipolar aprotic solvents. N-Butylpyrrolidinone, although structurally similar to NMP, is not mutagenic or reprotoxic, yet retains many of the characteristics of a dipolar aprotic solvent. This work introduces N-butylpyrrolidinone as a new solvent for cross-coupling reactions and other syntheses typically requiring a conventional dipolar aprotic solvent.

//////////////N-Butylpyrrolidinone, dipolar aprotic solvent, organic synthesis\

Bhandardhara, maharashtra, India

भंडारदरा

Bhandardara

Village in India

Bhandardara is a holiday resort village on the western ghat of India. The village is located in the Ahmednagar district of the state of Maharashtra, about 185 kilometers from Mumbai. Wikipedia

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Carboxylative cyclization of substituted propenyl ketones using CO2: transition-metal-free synthesis of [small alpha]-pyrones

SYNTHESIS Comments Off

Jul 292016

Carboxylative cyclization of substituted propenyl ketones using CO2: transition-metal-free synthesis of [small alpha]-pyrones

Green Chem., 2016, 18,4181-4184

DOI: 10.1039/C6GC01346E, Communication

Wen-Zhen Zhang, Ming-Wang Yang, Xiao-Bing Lu
Carboxylative cyclization of substituted 1-propenyl ketones via [gamma]-carboxylation using CO₂ provides an efficient, straightforward, and transition-metal-free access to [small alpha]-pyrone compounds.

http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C6GC01346E?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

Carboxylative cyclization of substituted propenyl ketones using CO₂: transition-metal-free synthesis of α-pyrones

Wen-Zhen Zhang,*^a Ming-Wang Yang^a and Xiao-Bing Lu^a

*Corresponding authors

^aState Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, P. R. China
E-mail: zhangwz@dlut.edu.cn

Green Chem., 2016,18, 4181-4184

DOI: 10.1039/C6GC01346E

Carbon dioxide is a green carboxylative reagent due to its non-toxic and renewable properties. Described herein is a carboxylative cyclization of substituted 1-propenyl ketones via γ-carboxylation using CO₂, which provides an efficient, transition-metal-free and straightforward access to important α-pyrone compounds from easily available substrates and CO₂.

////////////Carboxylative cyclization, substituted propenyl ketones, CO2, transition-metal-free synthesis, [small alpha]-pyrones

Rapid, metal-free and aqueous synthesis of imidazo[1,2-a]pyridine under ambient conditions

Uncategorized Comments Off

Jul 292016

Rapid, metal-free and aqueous synthesis of imidazo[1,2-a]pyridine under ambient conditions

Green Chem., 2016, Advance Article
DOI: 10.1039/C6GC01601D, Communication

Open Access

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.

Michael R. Chapman, Maria H. T. Kwan, Georgina E. King, Benjamin A. Kyffin, A. John Blacker, Charlotte E. Willans, Bao N. Nguyen
A route to access the privileged imidazo[1,2-a]pyridine scaffold in one step, 1-10 minutes using only aqueous NaOH, is reported.

Rapid, metal-free and aqueous synthesis of imidazo[1,2-a]pyridine under ambient conditions

Michael R. Chapman,^a Maria H. T. Kwan,^a Georgina E. King,^a Benjamin A. Kyffin,^a A. John Blacker,^a Charlotte E. Willans*^a and Bao N. Nguyen*^a

*Corresponding authors

^aInstitute of Process Research and Development, School of Chemistry, University of Leeds, Leeds, UK
E-mail: b.nguyen@leeds.ac.uk

Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC01601D

see………..http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C6GC01601D?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

see http://pubs.rsc.org/en/content/articlehtml/2016/gc/c6gc01601d

A novel, rapid and efficient route to imidazo[1,2-a]pyridines under ambient, aqueous and metal-free conditions is reported. The NaOH-promoted cycloisomerisations of N-propargylpyridiniums give quantitative yield in a few minutes (10 g scale). A comparison of common green metrics to current routes showed clear improvements, with at least a one order of magnitude increase in space-time-yield.

Scheme 1 Synthetic methods to assemble imidazo[1,2-a]pyridines.

Fig. 1 A scaled up reaction setup. (a) before reaction; (b) during addition of 1a (zoomed in); (c) phase separation at the end of the reaction (zoomed in).

2-Aminopyridine (6.12 g, 65.0 mmol), propargyl bromide (11.6 g of an 80 wt.% solution in toluene, 78 mmol, 1.2 equiv) and 2-propanol (200 mL) charged to a round bottomed flask and stirred at 50 C for 2 hours. After which, a pale yellow solid precipitated from solution. This was filtered and washed with diethyl ether (2 x 30 mL) followed by drying in vacuo to give product 1a in 11.1 g (52 mmol, 80% isolated yield). To a stirring solution of NaOH (1.90 g, 47.5 mmol) in deionised H2O (70 mL) was added 2-amino-1- (2-propynyl)pyridinium bromide 1a (10.0 g, 47.0 mmol) via powder addition funnel (a) over a period of 5 minutes. Immediately upon addition, the solution phase turned yellow (b – d) and a yellow oil became dispersed as a distinct separate phase (e). The oil (product) was subsequently extracted into EtOAc (2 × 30 mL) (f), dried over anhydrous MgSO4, filtered and concentrated under reduced pressure to afford imidazo[1,2-a]pyridine 2a as a spectroscopically pure pale yellow oil. Yield: 6.12 g, 98% yield.

2-Amino-1-(2-propynyl)pyridinium bromide 1a: 1

1 M. Bakherad, H. N. –Isfahani, A. Keivanloo, N. Doostmohammadi, Tetrahedron Lett. 2008, 49, 3819-3822

2-Aminopyridine was reacted according to the general procedure (vide supra), affording the product as a colourless solid. Yield: 0.88 g, 83% yield.

1H NMR (300 MHz, D2O): δ (ppm) 8.08 (d, J = 6.9 Hz, 1H, pyH), 7.93 (t, J = 16.2, 8.4 Hz, 1H, pyH), 7.17 (d, J = 8.4 Hz, 1H, pyH), 7.01 (t, J = 14.1, 6.9 Hz, 1H, pyH), 5.06 (d, J = 2.7 Hz, 2H, CH2), 3.18 (t, J = 5.1, 2.7 Hz, 1H, C≡CH).

13C{1H} NMR (100 MHz, D2O): δ (ppm) 153.8, 143.1, 138.5, 115.2, 113.9, 78.6, 73.2, 43.5.

HR-MS (ESI+ ): m/z 133.0756 [C8H9N2] + , calcd. [M – Br]+ 133.0760.

Anal. calcd. (%) for C8H9N2Br: C 45.10, H 4.26, N 13.15; found C 45.40, H 4.30, N 13.20.

Lit. data:1 1H NMR (500 MHz, DMSO-d6) 8.72 (s, 2H, NH2), 8.23 – 6.85 (m, 4H, pyH), 5.12 (s, 2H, CH2), 3.85 (s, 1H, CH).

13C NMR (125 MHz, DMSO-d6) 154.5, 143.6, 139.8, 115.8, 114.0, 80.5, 76.0, 43.9.

1H NMR BELOW 1a

2-Methylimidazo[1,2-a]pyridine 2a:1 2-Amino-1-(2-propynyl)pyridinium bromide (1a) was reacted according to the general procedure (vide supra), affording the product as a colourless oil which solidifies under vacuum at room temperature. Yield: 0.13 g, 100% yield.

1H NMR (300 MHz, CDCl3): δ (ppm) 8.24 (dt, J = 6.6, 2.1, 0.9 Hz, 1H, pyH), 7.58 (d, J = 9.0 Hz, 1H, pyH), 7.49 (s, 1H, imH), 7.20 (m, 1H, pyH), 6.80 (td, J = 9.0, 6.6, 0.9 Hz, 1H, pyH), 2.41 (d, J = 0.9 Hz, 3H, CH3).

13C{1H} NMR (75 MHz, CDCl3): δ (ppm) 143.2, 140.2, 126.5, 126.1, 115.2, 113.3, 110.2, 13.1.

HR-MS (ESI+ ): m/z 133.0759 [C8H9N2] + , calcd. [M + H]+ 133.0760.

Anal. calcd. (%) for C8H8N2: C 72.70, H 6.10, N 21.10; found C 72.70, H 6.50, N 20.75.

Lit. data:1 1H NMR (500 MHz, DMSO-d6) 8.29 (s, 1H, CH), 7.59 – 7.03 (m, 4H, pyH), 1.21 (s, 3H, CH3).

13C NMR (125 MHz, DMSO-d6) 148.0, 140.0, 137.1, 130.8, 130.1, 116.2, 114.5, 34.1.

1 M. Bakherad, H. N. –Isfahani, A. Keivanloo, N. Doostmohammadi, Tetrahedron Lett. 2008, 49, 3819-3822

//////////

Ring-locking enables selective anhydrosugar synthesis from carbohydrate pyrolysis

SYNTHESIS Comments Off

Jul 292016

Ring-locking enables selective anhydrosugar synthesis from carbohydrate pyrolysis

Green Chem., 2016, Advance Article
DOI: 10.1039/C6GC01600F, Paper

Li Chen, Jinmo Zhao, Sivaram Pradhan, Bruce E. Brinson, Gustavo E. Scuseria, Z. Conrad Zhang, Michael S. Wong
The nonselective nature of glucose pyrolysis chemistry can be controlled by preventing the sugar ring from opening and fragmenting.

Ring-locking enables selective anhydrosugar synthesis from carbohydrate pyrolysis

Li Chen,^a Jinmo Zhao,^b Sivaram Pradhan,^a Bruce E. Brinson,^b Gustavo E. Scuseria,^b Z. Conrad Zhang*^c and Michael S. Wong*^a^b^d^e

*Corresponding authors

^aDepartment of Chemical and Biomolecular Engineering, Rice University, Houston, USA
E-mail: mswong@rice.edu

^bDepartment of Chemistry, Rice University, Houston, USA

^cDalian National Laboratory of Clean Energy, Dalian Institute of Chemical Physics, Dalian, China
E-mail: zczhang@dicp.ac.cn

^dDepartment of Civil and Environmental Engineering, Rice University, Houston, USA

^eDepartment of Materials Science and NanoEngineering, Rice University, Houston, USA

Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC01600F

see ………………..http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C6GC01600F?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

The selective production of platform chemicals from thermal conversion of biomass-derived carbohydrates is challenging. As precursors to natural products and drug molecules, anhydrosugars are difficult to synthesize from simple carbohydrates in large quantities without side products, due to various competing pathways during pyrolysis. Here we demonstrate that the nonselective chemistry of carbohydrate pyrolysis is substantially improved by alkoxy or phenoxy substitution at the anomeric carbon of glucose prior to thermal treatment. Through this ring-locking step, we found that the selectivity to 1,6-anhydro-β-D-glucopyranose (levoglucosan, LGA) increased from 2% to greater than 90% after fast pyrolysis of the resulting sugar at 600 °C. DFT analysis indicated that LGA formation becomes the dominant reaction pathway when the substituent group inhibits the pyranose ring from opening and fragmenting into non-anhydrosugar products. LGA forms selectively when the activation barrier for ring-opening is significantly increased over that for 1,6-elimination, with both barriers affected by the substituent type and anomeric position. These findings introduce the ring-locking concept to sugar pyrolysis chemistry and suggest a chemical-thermal treatment approach for upgrading simple and complex carbohydrates.

////////Ring-locking , selective anhydrosugar, carbohydrate pyrolysis, synthesis

Anti-Aging Secret , A substance found in pomegranate fruit proved an effective anti-aging agent

Ayurveda Comments Off

Jul 292016

thumbnail image: Anti-Aging Secret

Anti-Aging Secret

A substance found in pomegranate fruit proved an effective anti-aging agent

http://www.chemistryviews.org/details/news/9605411/Anti-Aging_Secret.html?elq_mid=11072&elq_cid=1558306

UA improves fitness and extends lifespan.

CREDIT http://www.nature.com/nm/journal/vaop/ncurrent/full/nm.4132.html

CREDIT ChemistryViews

/////////////pomegranate fruit, anti-aging agent

Varenicline (Chantix™) バレニクリン酒石酸塩

Uncategorized Comments Off

Jul 282016

Varenicline (Chantix™)

Varenicline

MF C₁₃H₁₃N₃
MW 211.26

(1R,12S)-5,8,14-Triazatétracyclo[10.3.1.0^2,11.0^4,9]hexadéca-2,4,6,8,10-pentaène [French] [ACD/IUPAC Name]

6,10-Methano-6H-azepino[4,5-g]quinoxaline, 7,8,9,10-tetrahydro-, (6R,10S)- [ACD/Index Name]

Champix

(1R,12S)-5,8,14-triazatetracyclo[10.3.1.02,11.04,9]hexadeca-2(11),3,5,7,9-pentaene

CP-526,555

MFCD08460603

MFCD10001497

UNII:W6HS99O8ZO

APPROVALS

FDA MAY 10, 2006

EMA SEPT 2006

PMDA JAPAN JAN 25 2008

Varenicline (trade name Chantix and Champix usually in the form of varenicline tartrate), is a prescription medication used to treatnicotine addiction. Varenicline is a nicotinic receptor partial agonist—it stimulates nicotine receptors more weakly than nicotine itself does. In this respect it is similar to cytisine and different from the nicotinic antagonist, bupropion, and nicotine replacement therapies(NRTs) like nicotine patches and nicotine gum. As a partial agonist it both reduces cravings for and decreases the pleasurable effects of cigarettes and other tobacco products. Through these mechanisms it can assist some patients to quit smoking.

Varenicline

CAS Registry Number: 249296-44-4

CAS Name: 7,8,9,10-Tetrahydro-6,10-methano-6H-pyrazino[2,3-h][3]benzazepine

Additional Names: 5,8,14-triazatetracyclo[10.3.1.02,11.04,9]hexadeca-2(11)-3,5,7,9-pentaene

Manufacturers’ Codes: CP-526555

Molecular Formula: C13H13N3

Molecular Weight: 211.26

Percent Composition: C 73.91%, H 6.20%, N 19.89%

Literature References: Nicotinic a4b2 acetylcholine receptor partial agonist. Prepn: P. R. P. Brooks, J. W. Coe, WO 0162736(2001 to Pfizer). Synthesis, receptor binding studies, and in vivo dopaminergic acitvity: J. W. Coe et al., J. Med. Chem. 48, 3474 (2005). Metabolism: R. S. Obach et al., Drug Metab. Dispos. 34, 121 (2006).

Derivative Type: Tartrate

CAS Registry Number: 375815-87-5

Trademarks: Champix (Pfizer)

Molecular Formula: C13H13N3.C4H6O6

Molecular Weight: 361.35

Percent Composition: C 56.51%, H 5.30%, N 11.63%, O 26.57%

Therap-Cat: Aid in smoking cessation.

バレニクリン酒石酸塩
Varenicline Tartrate

C₁₃H₁₃N₃▪C₄H₆O₆ : 361.35
[375815-87-5]

Medical uses

Varenicline is used for smoking cessation. In a 2009 meta-analysis varenicline was found to be more effective than bupropion (odds ratio 1.40) and NRTs (odds ratio 1.56).^[1]

A 2013 Cochrane overview and network meta-analysis concluded that varenicline is the most effective medication for tobacco cessation and that smokers were nearly three times more likely to quit on varenicline than with placebo treatment. Varenicline was more efficacious than bupropion or NRT and as effective as combination NRT for tobacco smoking cessation.^[2]^[3]

The United States’ Food and Drug Administration (US FDA) has approved the use of varenicline for up to twelve weeks. If smoking cessation has been achieved it may be continued for another twelve weeks.^[4]

Varenicline has not been tested in those under 18 years old or pregnant women and therefore is not recommended for use by these groups. Varenicline is considered a class C pregnancy drug, as animal studies have shown no increased risk of congenital anomalies, however, no data from human studies is available.^[5] An observational study is currently being conducted assessing for malformations related to varenicline exposure, but has no results yet.^[6] An alternate drug is preferred for smoking cessation during breastfeeding due to lack of information and based on the animal studies on nicotine.^[7]

Varenicline L-tartrate (Compound I) is the international commonly accepted name for 7,8,9,10- tetrahydro-6, 10-methano-6i7-pyrazino [2, 3- h] [3 ] benzazepme, (2R, 3R) -2 , 3-dihydroxybutanedioate (1:1) (which is also known as 5,8,14- tπazatetracyclo [10.3.1. O²‘¹¹. O⁴‘⁹] -hexadeca-2 (11) , 3, 5, 7, 9-pentaene, (2R, 3R)-2,3- dihydroxybutanedioate (1:1)) and has an empirical formula of C13H13N3 ^• C4H6O6 and a molecular weight of 361.35. Varenicline L-tartrate is a commercially marketed pharmaceutically active substance known to be useful for the treatment of smoking addiction.

Varenicline L-tartrate is a partial agonist selective for (X₄β₂ nicotinic acetylcholine receptor subtypes. In the United States, varenicline L-tartrate is marketed under the name Chantix™ for the treatment of smoking cessation. Varenicline base and its pharmaceutically acceptable acid addition salts are described in U.S. Patent No. 6,410,550. In particular, Example 26 of U.S. Patent No. 6,410,550 describes the preparation of varenicline hydrochloride salt using 1- (4 , 5-dinitro-10- aza-tπcyclo [6.3.1.O²‘⁷] dodeca-2, 4, 6-trien-10-yl) -2,2,2- tπfluoroethanone (compound of formula (III)) as starting compound. On the other hand, Example HA) of U.S. Patent No. 6,410,550 illustrates the preparation of compound of formula (III) via nitration of compound of formula (II) using an excess of nitronium triflate (>4 equiv) as a nitrating agent. The process disclosed in U.S. Patent No. 6,410,550 is depicted in Scheme 1.

VareniclineΗCl

Scheme 1

However, Coe et al., J. Med. Chem., 48, 3474 (2005), describes the same process and examples as U.S. Patent No. 6,410,550, and it also reveals that this process affords intermediate ortho-4 , 5-dinitrocompound of formula (III) together with the meta-3, 5-dinitro- isomer (i.e. the meta-dinitrocompound) in a ratio 9:1. The presence of the meta-dinitrocompound may affect not only the purity of the intermediate compound of formula III but it may also have an effect on the purity of the final varenicline tartrate, given that it can be carried along the synthetic pathway and/or it can also give rise to other derivative impurities. Thereby, as well as in U.S. Patent No. 6,410,550, in order to isolate pure compound of formula (III) , the raw product is triturated with ethyl acetate/hexane to afford compound of formula (III) with 77% yield. Additionally, the mother liquor is purified by chromatography on silica gel to improve the yield to a total of 82.8%. However, this process is not desirable for industrial implementation since it requires extensive and complicated purification procedures, i.e. trituration of the solid product along with column chromatography purification of the mother liquor, which is not very efficient or suitable for industrial scale-up.

Several improved processes for the synthesis of varenicline or its salts have been reported in the literature (e.g. WO2006/090236) . However, none of these processes tackle the optimization of the purification step of compound of formula (III).

There is therefore the need for providing an improved process for the preparation of varenicline L- tartrate which involves simple experimental procedures well suited to industrial production, which avoids the use of column chromatography purifications, and which affords high pure varenicline L-tartrate which hence can be used directly as a starting product for the preparation of the marketed pharmaceutical speciality.

Additionally, it has been observed that varenicline L-tartrate is usually obtained as a yellow solid under – A –

standard synthetic conditions. In this regard, colour must be attributed to the presence of some specific impurities that may or may not be detectable by conventional methods such as HPLC. The presence of impurities may adversely affect the safety and shelf life of formulations. In this connection, International application No. WO2006/090236 describes the isolation of vareniclme L- tartrate as a white solid. However, in order to remove coloured impurities, the varenicline L-tartrate obtained in WO2006/090236 is treated with a particular activated carbon having a specific grade (i.e. Darco KB-B™) . In fact, Example 5 of WO2006/090236 describes a large reprocessing step which comprises: dissolving varenicline L-tartrate in water, adding toluene, basifying with NaOH aqueous solution, collecting the toluene phase containing varenicline free base, distilling, adding methanol, azeotropically distilling the mixture, and adding more methanol to obtain a methanolic solution containing varenicline free base, adding Darco KB-B™ (10% w/w) , stirring for one hour, filtering through a pad of celite, and treating with L-tartaric acid to give varenicline L- tartrate salt as a white solid. Further, WO2006/090236 provides the absorbance at 430 nm of a varenicline L- tartrate salt solution, either in dichloromethane or in toluene, with or without using Darco KB-B™ activated carbon. However, this measure cannot be used to corroborate the whiteness of the solid varenicline L- tartrate. In addition, Example 3 of International application No. WO2002/092089, also disclose the preparation of varenicline L-tartrate polymorphic form C (i.e. a hydrate polymorph) as a white precipitate. Therefore, there is also a need for a simple and efficient method for preparing varenicline L-tartrate with enhanced whiteness and having a high purity.

SYNTHESIS

Synthesis of Intermediate VIII

Paper

J. Med. Chem. 48, 3474 (2005).

http://pubs.acs.org/doi/pdf/10.1021/jm050069n

PATENT

https://www.google.com/patents/WO2001062736A1?cl=en

CLIP

Profiles of Drug Substances, Excipients and Related Methodology, Volume 37

edited by Harry G. Brittain

SYNTHESIS

DOI: 10.1021/jm00190a020
DOI: 10.1021/jm050069n

CLIP

Scheme (I) compound patent US6410550B1 is provided adjacent difluorobromobenzene as raw materials by DA reaction, oxidation, cyclization, debenzylation get varenicline intermediate (II). The synthesis route is as follows:

CLIP

Patent CN101693712A mainly given varenicline intermediate (II) The preparation process is different from the compound patented. After the five-step method patents cited compounds. The entire route is longer, while using a large number of precious metal catalysts and reaction conditions need very strict control, inappropriate EVAL industry production.

CLIP

PATENT

CN 102827079

A varenicline intermediate 2,3, 4, 5-tetrahydro-1,5-methylene bridge synthesis -1H-3- benzazepine hydrochloride, which comprises the following Step: (1) 2-indanone of formula 3 and the compound and paraformaldehyde under alkaline or acidic conditions Mannich reaction, as shown in general formula 2 intermediate; (2) the step (I) obtained through reaction of Formula 2 intermediate under basic or acidic conditions by reducing the role of the carbonyl group is reduced to a methylene group, and get varenicline intermediate (II) by debenzylation, the reaction is:

Wherein, R groups are selected from _H, _Me, _Et, _iPr> _t_Bu.

Figure 2;

Wherein, R group is -H, -Me, -Et, -iPr or -t_Bu.

(2) Step (I) obtained by the reaction intermediates of formula under basic or acidic conditions by reducing the role of the carbonyl group is reduced 2 methylene, and get by debenzylation cutting Lenk Lin intermediate (II);

CLIP

Varenicline, a nicotinic 􀀁4􀀂2 partial agonist, was approved in the US for the treatment of smoking cessation in May of 2006. It was developed and marketed by Pfizer as a treatment for cigarette smokers who want to quit. Varenicline partially activates the nicotinic receptors and thus reduces the craving for cigarette that smokers feel when they try to quit smoking. By mitigating this craving and antagonizing nicotine activity without other symptoms, this novel drug helps quitting this dangerous addiction easier on the patients [6,52]. Several modifications [54,55] to the original synthesis [53,56] have been reported in the literature, including an improved process scale synthesis of the last few steps (Scheme 15) [57]. The Grignard reaction was initiated on a small scale by addition of 2-bromo fluorobenzene 113 to a slurry of Magnesium turnings and catalytic 1,2-dibromoethane in THF and heating the mixture until refluxing in maintained. To this refluxing mixture was added a mixture of the 2-bromo fluorobenzene 113 and cyclopentadiene 114 over a period of 1.5 h. After complete addition, the reaction was allowed to reflux for additional 1.5 h to give the Diels- Alder product 115 in 64% yield. Dihydroxylation of the olefin 115 by reacting with catalytic osmium tetraoxide in the presence of N-methylmorpholine N-oxide (NMO) in acetone: water mixture at room temperature provided the diol 116 in 89% yield. Oxidative cleavage of diol 116 with sodium periodate in biphasic mixture of water: DCE at 10ºC provided di-aldehyde 117 which was immediately reacted with benzyl amine in the presence of sodium acetoxyborohydride to give benzyl amine 118 in 85.7% yield. The removal of the benzyl group was effected by hydrogenation of the HCl salt in 40-50 psi hydrogen pressure with 20% Pd(OH)2 in methanol to give amine hydrochloride 119 in 88% yield. Treatment of amine 119 with trifluoroacetic anhydride and pyridine in dichloromethane at 0ºC gave trifluoroacetamide 120 in 94% yield. Dinitro compound 121 was prepared by addition of trifluoroacetamide 120 to a mixture of trifluoromethane sulfonic acid and nitric acid, which was premixed, in dichloromethane at 0ºC. Reduction of the dinitro compound 121 by hydrogenation at 40-50 psi hydrogen in the presence of catalytic 5%Pd/C in isopropanol:water mixture provided the diamine intermediate 122 which was quickly reacted with glyoxal in water at room temperature for 18h to give compound 123 in 85% overall yield. The trifluoroacetamide 123 was then hydrolyzed with 2 M sodium hydroxide in toluene at 37-40ºC for 2-3h followed by preparation of tartrate salt in methanol to furnish varenicline tartrate (XV).

[52]Keating, G.; Siddiqui, M. A. A. CNSdrugs, 2006, 11, 946.
[53] Coe, J. W.; Brooks, P. R.; Vetelino, M. G.; Wirtz, M. C.; Arnold,E. P. ; Huang, J.; Sands, S. B.; Davis, T. I.; Lebel, L. A.; Fox, C.
B.; Shrikhande, A.; Heym, J. H.; Schaeffer, E.; Rollema, H.; Lu,Y.; Mansbach, R. S.; Chambers, L. K.; Rovetti, C. C.; Schulz, D.
W.; Tingley, III, F. D.; O’Neill, B. T. J. Med. Chem., 2005, 48,3474.
[54] Brooks, P. R.; Caron, S.; Coe, J. W.; Ng, K. K.; Singer, R. A.;Vazquez, E.; Vetelino, M. G.; Watson, Jr. H. H.; Whritenour, D.
C.; Wirtz, M. C. Synthesis, 2004, 11, 1755.
[55] Singer, R. A.; McKinley, J. D.; Barbe, G.; Farlow, R. A. Org. Lett.,2004, 6, 2357.
[56] Coe, J. W.; Brooks, P. R. P. US-6410550 B1, 2002.
[57] Busch, F. R.; Hawkins, J. M.; Mustakis, L. G.; Sinay, T. G., Jr.;Watson, T. J. N.; Withbroe, G. J. WO-2006090236 A1, 2006.

PATENT

WO 2002085843

https://google.com/patents/WO2002085843A2?cl=en

PATENT

https://www.google.com/patents/EP2204369A1?cl=en

Varenicline (a compound I of formula I) is the international commonly accepted non-proprietary name for 7,8,9,10-tetrahydro-6,10-methano-6H-pyrazino[2,3-h][3]benzazepine (which is also known as 5,8,14-triazatetracyclo[10.3.1.0^2,11.0^4,9]-hexadeca-2(11),3,5,7,9-pentaene), and has an empirical formula of C₁₃H₁₃N₃ and a molecular weight of 211.26.

The L-tartrate salt of varenicline is known to be therapeutically useful and is commercially marketed for the treatment of smoking addiction. Varenicline L-tartrate is a partial agonist selective for α₄β₂ nicotinic acetylcholine receptor subtypes. In the United States, varenicline L-tartrate is marketed under the trade mark Chantix and is indicated as an aid to smoking cessation treatment.

Varenicline base and its pharmaceutically acceptable acid addition salts are described in U.S. Patent No. 6,410,550 . In particular, the preparation of varenicline provided in this reference makes use of 10-aza-tricyclo[6.3.1.0^2,7]-dodeca-2(7),3,5-triene (a compound of Formula VI), as a key intermediate compound (see Scheme 1 below). Specifically, Example 1 of U.S. Patent No. 6,410,550 describes the synthetic preparation of key intermediate compound of Formula VI as depicted in Scheme 1.

1,2,3,4-tetrahydro-1,4-methano-naphthalene-cis-2,3-diol (a compound of Formula III), and / or indane-1,3-dicarbaldehyde (a compound of Formula IV).

Example 1: Preparation of 1,2,3,4-tetrahydro-1,4-methano-naphthalene-cis-2,3-diol (a compound of Formula III)

A 10mL round bottom flask was charged with a compound of formula II (142mg, 1mmol), N-methylmorpholine-N-oxide (120mg, 1.03mmol), tert-butanol (3mL) and water (1mL). FibreCat^™ 3003 (OsO₄ anchored onto a polymeric support) (11.6mg, 0.0025mmol) was added to this solution and the mixture was heated to reflux. Complete conversion to a compound of formula III was detected by GC, method A, after 48h.

Example 2: Preparation of 1,2,3,4-tetrahydro-1,4-methano-naphthalene-cis-2,3-diol (a compound of Formula III)Step A) Preparation of hexadecyl-trimethylammoniumpermanganate (HTAP):

HTAP was prepared from ion exchange reaction between hexadecyltrimethylammoniumbromide and potassium permanganate.

Potassium permanganate (17.38g, 0.11mol, 1equiv.) was dissolved in 500mL water. A solution of hexadecyltrimethylammoniumbromide (40.10g, 0.11mol, 1equiv) in 500mL water was added drop-wise over 45 min at 20-22°C, and the mixture stirred for 30 minutes at this temperature. The precipitated solid was collected by filtration, washed with water (3 x 100mL) and dried under vacuum at 35°C for 24 hours to give 34.38g of HTAP as a light purple solid.

Step B) Preparation of a compound of formula III:

Compound II (3.52g, 24.8mmol, 1equiv.) was dissolved in anhydrous tetrahydrofuran (80mL) and a solution of HTAP (10g, 24.8mmol, 1.0equiv.) in anhydrous tetrahydrofuran (125mL) was added drop-wise at 23-30°C over 45min. The reaction was monitored by TLC (hexane-ethyl acetate = 1:1). After complete reaction the mixture was cooled to below 10°C, and methyl tert-butyl ether (50mL) and 5% aqueous NaOH solution (50mL) were added and the mixture stirred for 30min. The solid was removed by filtration, and washed with methyl tert-butyl ether (2 x 30mL). The combined layers of the filtrate were separated and the aqueous phase extracted with methyl tert-butyl ether (2 x 30mL). The organic layers were combined and washed with 5% aqueous NaOH solution (50mL), water (2 x 50mL), dried over MgSO₄, filtered and concentrated to obtain a dark green solid. This residue was suspended in acetone (15mL) and collected by filtration, washing with additional acetone (3 x 5mL). The product was dried under vacuum at 40°C to give 2.215g (50.7% yield) as a white crystalline solid.

Analytical data: m.p. = 178.8-179.3°C; ¹H-NMR: See Figure 1; ¹³C-NMR: See Figure 2.

Example 3: Preparation of indane-1,3-dicarbaldehyde (a compound of Formula IV)

A 25 mL round bottom flask was charged with a compound of formula I (142mg, 1mmol), Ruthenium (III) chloride hydrate (Aldrich, Reagent Plus^™) (7.2mg, 0.035mmol), acetonitrile (8.5mL) and water (1.1mL). The solution was heated to 45°C and sodium periodate (449mg, 2.1mmol) was added portionwise over 25 minutes. After 1h, the reaction was cooled to ambient temperature and filtered. The solids were washed with ethyl acetate (3 x 2mL) and water (3mL). The filtrate was concentrated under vacuum and 5mL of water were added to the obtained residue. The mixture was extracted with ethyl acetate (2 x 5mL) and the combination of the organic layers was washed with water (3 x 5mL), dried with MgSO₄ and concentrated under vacuum to obtain a compound of formula IV (118mg) in 68% yield, 70.9% purity (analyzed by GC, method A).

PATENT

WO 199935131, WO 2002092089, US 2013030179

PATENT

https://www.google.com/patents/WO2009065872A2?cl=en

Example 1: Preparation of 7,8,9,10- tetrahydro-6, 10-methano-6H-pyrazino [2, 3-h] [3] benzazepine L-tartrate (i.e. varenicline L-tartrate)

A) Preparation of compound of formula (III)

This example is based on U.S. Patent No. 6,410,550.

A 250 mL round bottom flask with thermometer, condenser, addition funnel and magnetic stirring was charged with 10-aza-tricyclo [ 6.3.1. O²‘⁷] dodeca-2, 4, 6- triene para-toluene sulfonic acid salt (12.4g, 37.5 mmol) and 44 mL of CH₂Cl₂. Triethylamine (8.3 g, 82.5 mmol) was added to the slurry and the resulting solution was cooled to 0-5 ⁰C. The addition funnel was charged with a solution of (CF₃CO)₂O (8.1q, 41.25 mmol) in 19 mL of CH₂Cl₂. This solution was slowly added to the reaction mixture, maintaining the temperature < 15 ⁰C. The resulting mixture was stirred for 1 hour, and the complete conversion was monitored by GC. The crude reaction mixture was washed with water (2 * 40 mL) and brine (40 mL) . The organic phase was used in the next step without further purification.

On the other hand, a 500 mL round bottom flask with thermometer, condenser, addition funnel and magnetic stirring was charged with CF₃SO₃H (25.9 g, 172.5 mmol), CH₂Cl₂ (110 mL) and cooled to 0-5 ⁰C. At this temperature, fuming nitric acid (5.4 g, 86.25 mmol) was added slowly. To the resulting slurry at 0-5 ⁰C, the solution obtained in the previous step was slowly added, maintaining the temperature < 15 ⁰C. After the addition, the reaction mixture was stirred overnight. The complete dinitration was confirmed by GC. The crude reaction mixture was poured into water (60 mL) an ice (80 g) and stirred. The phases were separated and the aqueous phase was extracted with CH₂Cl₂ (3 x 50 mL) . The mixture of the organic phases was washed with aqueous saturated NaHCO₃, dried over Na₂SO₄ and volatiles evaporated under vacuum to obtain 11.9 g of a solid that was suspended and stirred for 2 hours in AcOEt (12 mL) and hexanes (24 mL) . The solid was filtered and washed with hexanes to obtain the compound of formula (III), 9.1g with a purity of 88.9% by GC (9.8% of meta-dimtrocompound impurity) .

B) Preparation of compound of formula (IV)

This example is based on International Patent No. WO/2006/090236.

A 200 mL autoclave was charged with (III) (9.1 g, 26.3 mmol), damp 5% Pd/C 50% and 180 mL of a 2- propanol/water (80/20 wt/wt) . The reaction was stirred under 50 psi of hydrogen for 18 hours. The complete hydrogenation was confirmed by GC analysis. The reaction was filtered through Celite and washed with 2-propanol (40 mL) . To this solution, K₂HPO₄(458 mg, 2.63 mmol) was added. The mixture was cooled at 0-5 ⁰C and a solution of 4.07 g of 40% aqueous glyoxal diluted with water (14.5 mL) was added slowly. The resulting solution was stirred 2 hours at this temperature and overnight at room temperature. The complete conversion was confirmed by GC analysis. The reaction was concentrated under vacuum to a volume of 68 mL and water (128 mL) was added drop- wise. The resulting suspension was stirred for 2 hours at room temperature, 1 hour in a ice/water bath, filtered, washed with water (20 mL) and dried m a oven at 50 ⁰C to obtain the compound of formula (IV), 6.78 g.

C) Preparation of vareniclme L-tartrate (compound of formula (I) )

This example is based on International Patent No. WO/2006/090236.

A 250 mL round bottom flask with thermometer, condenser, and magnetic stirring was charged with compound of formula (IV) (6.78 g, 22 mmol) and toluene

(47 mL) . To this solution was added a solution of NaOH (2.7 g, 68.2 mmol) in water (34 mL) . The mixture was heated to 40⁰C and stirred for 4 hours. The complete hydrolysis was confirmed by GC analysis. Toluene (68 mL) was added and the reaction was cooled. The phases were separated and the aqueous phase was extracted with toluene (30 mL) . The organic phases were evaporated under vacuum. The residue was dissolved in MeOH (90 mL) and evaporated again. The final residue was dissolved in 156 mL of MeOH. 1.3 g of activated carbon “Darco G-60 100 mesh” were added and the mixture was stirred for 30 min and filtered through Celite to obtain an intense yellow solution. The process with activated carbon was repeated without any improvement in the colour. This solution was added drop-wise over a solution of L- tartaric acid (3.63 g, 24.2 mmol) in MeOH (47 mL) . The slurry was stirred for 72 hours at room temperature, filtered, washed with MeOH and dried in an oven at 50 ⁰C for 8 hours, to obtain 5.05 g of varenicline L-tartrate as a yellow solid with a 95.5% purity by HPLC (4.4% of unknown impurity A). Colour L: 92.75, a*: -7.19, b*:43.08.

Comparative Example 2: Preparation of 7,8,9,10- tetrahydro-6, 10-methano-6H-pyrazmo [2, 3-h] [3 ] benzazepine L-tartrate (i.e. varenicline L-tartrate) A) Preparation of compound of formula (IV)

This example is based on International Patent No. WO/2006/090236.

A 200 mL autoclave was charged with (III) prepared according to Comparative Example 1.A) (4.1 g) , 123 mg of damp 5% Pd/C 50% and 81 mL of a 2-propanol/water (80/20 wt/wt) . The reaction was stirred under 50 psi of hydrogen for 24 hours. The complete hydrogenation was confirmed by GC analysis. The reaction was filtered through Celite and washed with 2-propanol (16 mL) . To this solution, K₂HPO₄ (207 mg, 1.19 mmol) was added. The mixture was cooled at 0-5 ⁰C and a solution of 1.84 g of 40% aqueous glyoxal diluted with water (6.6 mL) was added slowly. The resulting solution was stirred 2 hours at this temperature and overnight at room temperature. The complete conversion was confirmed by GC analysis. The reaction was concentrated under vacuum to a volume of 30 mL and water (56 mL) was added drop-wise. The resulting suspension was stirred for 2 hours at room temperature, 1 hour in a ice/water bath, filtered, washed with water and dried in a oven at 50 ⁰C to obtain 3.15 g of compound of formula (IV) .

B) Preparation of vareniclme L-tartrate (compound of formula (I) )

This example is based on International application No. WO/2006/090236. A 100 mL round bottom flask with thermometer, condenser, and magnetic stirring was charged with

7, 8, 9, 10-tetrahydro-8- (tπfluoroacetyl) -6, 10-methano-6H- pyrazino [2 , 3-h] [3] benzazepine, i.e. compound of formula

(IV) (3.14 g, 10.2 mmol) and toluene (22 mL) . To this solution was added a solution of NaOH (1.3 g, 31.6 mmol) in water (16 mL) . The mixture was heated to 40 ⁰C and stirred for 2.5 hours. The complete hydrolysis was confirmed by GC analysis. Toluene (30 mL) was added and the reaction was cooled. The phases were separated and the aqueous phase was extracted with toluene (15 mL) . The organic phases were evaporated under vacuum. The residue was dissolved in MeOH (45 mL) and evaporated again. The final residue was dissolved m 70 mL of MeOH. 314 mg of activated carbon “Darco G-60 100 mesh” were added and the mixture was stirred for 30 mm and filtered through Celite to obtain a yellow solution. This solution was added drop-wise over a solution of L- tartaπc acid (1.68 g, 11.22 mmol) m MeOH (22 mL) . The slurry was stirred for 1 hour at room temperature, filtered, washed with MeOH (2 x 5 mL) and dried under vacuum, to obtain vareniclme L-tartrate (2.48 g) as a yellow solid with a 95.6% purity by HPLC (4.4% of unknown impurity A). Colour L: 99.50, a*: -4.98, b*:43.02

Comparative Example 3: Preparation of 7,8,9,10- tetrahydro-6, 10-methano-6H-pyrazino [2, 3-h] [3 ] benzazepine L-tartrate (i.e. vareniclme L-tartrate)

This example is based on International application No. WO/2002/092089.

2 g of vareniclme L-tartrate as obtained from Comparative Example 1 were dissolved in 3 mL of water.

To this solution, 100 mL of CH₃CN were added, and the resulting slurry was stirred for 10 mm and filtered.

After drying the product was analysed to be a 98.2% purity by HPLC (1.7% of unknown impurity A) . Colour L: 91.44, a*: -3.24, b* : 33.47

Example 1: Preparation of 7, 8, 9, lO-tetrahydro-6, 10- methano-6H-pyrazmo [2, 3-h] [3] benzazepine L-tartrate

(i.e. vareniclme L-tartrate)

A) Preparation of compound of formula (III) This example is based on U.S. Patent No. 6,410,550, except for the purification step, which is the object of the present invention (i.e. crystallization in toluene) .

A 500 mL round bottom flask with thermometer, condenser, addition funnel and magnetic stirring was charged with 10-aza-tricyclo [ 6.3.1. O²‘⁷] dodeca-2, 4, 6- tπene para-toluene sulfonic acid salt (32.5g, 98.2 mmol) and 115 mL of CH₂Cl₂. Triethylamine (21.8 g, 216 mmol) was added to the slurry and the resulting solution was cooled to 0-5 ⁰C. The addition funnel was charged with a solution of (CF₃CO)₂O (22.7 g, 108 mmol) in 50 mL of CH₂Cl₂. This solution was slowly added to the reaction mixture, maintaining the temperature < 15 ⁰C. The resulting mixture was stirred for 1 hour, and the complete conversion was monitored by GC. The crude reaction mixture was washed with water (2 x 100 mL) and brine (100 mL) . The organic phase was used in the next step without further purification.

A l L round bottom flask with thermometer, condenser, addition funnel and magnetic stirring was charged with CF₃SO₃H (67.8 g, 452 mmol), CH₂Cl₂ (280 mL) and cooled to 0-5 ⁰C. At this temperature, fuming nitric acid (14.2 g, 226 mmol) was slowly added. To the resulting slurry at 0-5 ⁰C, the solution obtained in the previous step was slowly added, maintaining the temperature < 15 ⁰C. After the addition, the reaction mixture was stirred overnight. The complete dinitration was confirmed by GC. The crude reaction mixture was poured into water (150 mL) an ice (200 g) and stirred. The phases were separated and the aqueous phase was extracted with CH₂Cl₂ (100 mL) . The mixture of the organic phases was washed with aqueous saturated NaHCO₃ (2×100 mL) , water (100 mL) , dried over Na₂SO₄ and volatiles evaporated under vacuum to obtain 30.5 g of a solid with a 83.6% purity by GC (12.5% of meta- dinitrocompound impurity) . 20 g of this solid were crystallized in toluene (100 mL) to obtain the compound of formula (III), 15 g of a pale brown solid with a 98.5 % purity by GC (meta-dinitrocompound impurity not detected) .

B) Preparation of compound of formula (IV) This example is based on International Patent No. WO/2006/090236.

A 200 mL autoclave was charged with (III) (9.1 g, 26.3 mmol, crystals from toluene), damp 5% Pd/C 50% and 180 mL of a 2-propanol/water (80/20 wt/wt) . The reaction was stirred under 50 psi of hydrogen for 18 hours. The complete hydrogenation was confirmed by GC analysis. The reaction was filtered over Celite and washed with 2- propanol (40 mL) . To this solution, K₂HPO₄ (458 mg, 2.63 mmol) was added. The mixture was cooled at 0-5 ⁰C and a solution of 4.07 g of 40% aqueous glyoxal diluted with water (14.5 mL) was added slowly. The resulting solution was stirred 2 hours at this temperature and overnight at room temperature. The complete conversion was confirmed by GC analysis. The reaction was concentrated under vacuum to a volume of 68 mL and water (128 mL) was added drop-wise. The resulting suspension was stirred for 2 hours at room temperature, 1 hour in a ice/water bath, filtered, washed with water (20 mL) and dried m a oven at 50 ⁰C to obtain the product, 7.16 g of compound of formula (IV) with a 99.9% purity by HPLC. C) Preparation of varenicline L-tartrate (compound of formula ( I) )

Thrs example rs based on International Patent No. WO/2006/090236. A 250 mL round bottom flask with thermometer, condenser, and magnetic stirring was charged with a solution of NaOH (2.89 g, 72.23 mmol) in water (36 mL) , compound of formula (IV) (7.15 g, 23.3 mmol) and toluene (50 mL) . The mixture was heated to 40 ⁰C and stirred for 4 hours. The complete hydrolysis was confirmed by GC analysis. Toluene (71 mL) was added and the reaction was cooled. The phases were separated and the aqueous phase was extracted with toluene (36 mL) . The organic phases were evaporated under vacuum. The residue was dissolved in MeOH (110 mL) and evaporated again. The final residue was dissolved in 164 mL of MeOH. 750 mg of activated carbon “Darco G-60 100 mesh” were added and the mixture was stirred for 30 min and filtered through Celite to obtain a yellow solution. This solution was added drop- wise over a solution of L-tartaric acid (3.84 g, 25.6 mmol) in MeOH (50 mL) . The slurry was stirred for 14 hours at room temperature, filtered, washed with MeOH and dried under vacuum, to obtain varenicline L-tartrate

(7.04 g) as an off-white solid with a >99.9% purity by HPLC (unknown impurity A not detected) . Colour L: 94.39, a*: 2.27, b*:9.02.

Post-marketing surveillance

No evidence for increased risks of cardiovascular events, depression, or self-harm with varenicline versus nicotine replacement therapy has been found in one post-marketing surveillance study.^[23]

Mechanism of action

Varenicline displays full agonism on α₇ nicotinic acetylcholine receptors.^[24]^[25] And it is a partial agonist on the α₄β₂, α₃β₄, and α₆β₂ subtypes.^[26] In addition, it is a weak agonist on the α₃β₂ containing receptors.

Varenicline’s partial agonism on the α₄β₂ receptors rather than nicotine’s full agonism produces less effect of dopamine release than nicotine’s. This α₄β₂ competitive binding, reduces the ability of nicotine to bind and stimulate the mesolimbic dopamine system – similar to the method of action of buprenorphine in the treatment of opioid addiction.^[3]

Pharmacokinetics

Most of the active compound is excreted by the kidneys (92–93%). A small proportion is glucuronidated, oxidised, N-formylated or conjugated to a hexose.^[27] The elimination half-life is about 24 hours.

History

Use of Cytisus plant as a smoking substitute during World War II^[28] led to use as a cessation aid in eastern Europe and extraction of cytisine.^[29] Cytisine analogs led to varenicline at Pfizer.^[30]^[31]^[32]

Varenicline received a “priority review” by the US FDA in February 2006, shortening the usual 10-month review period to 6 months because of its demonstrated effectiveness inclinical trials and perceived lack of safety issues.^[33] The agency’s approval of the drug came on May 11, 2006.^[4] On August 1, 2006, varenicline was made available for sale in the United States and on September 29, 2006, was approved for sale in the European Union.^[34]

SEE

www.emea.europa.eu/humandocs/PDFs/EPAR/champix/H-699-en6.pdf.

Busch FR, Concannon PE, Handfield RE, McKinley JD, McMahon ME, Singer RA, Watson TJ, Withbroe GJ, Stivanello M, Leoni L, Bezze C. Synthesis of (1 (Aminomethyl)-2,3-dihydro-1H-inden-3-yl)methanol: Structural Confirmation of the Main Band Impurity Found in Varenicline® Starting Material.Synth Commun. 2008;38:441–447. http://dx.doi.org/10.1080/00397910701771231.

Varenicline standards and impurity controls. www.freepatentsonline.com/US2007/0224690.html.

N-formyl and N-methyl degradation products. www.freepatentsonline.com/y2004/0235850.html.

Methods of reducing degradant formation in pharmaceutical compositions of Varenicline.www.freepatentsonline.com/y2008/0026059.html.

Varenicline standards and impurity controls. www.freepatentsonline.com/EP2004186.html.

Satheesh B, Kumarpulluru S, Raghavan V, Saravanan D. UHPLC Separation and Quantification of Related Substances of Varenicline Tartrate Tablet. Acta Chromatogr. 2010;22:207–218.http://dx.doi.org/10.1556/AChrom.22.2010.2.4.

US6410550	Nov 13, 1998	Jun 25, 2002	Pfizer Inc	Aryl fused azapolycyclic compounds
WO2009155403A2 *	Jun 18, 2009	Dec 23, 2009	Teva Pharmaceutical Industries Ltd.	Processes for the preparation of varenicline and intermediates thereof

Reference
1	*	BHUSHAN, VIDYA; RATHORE, RAJENDRA; CHANDRASEKARAN, S.: “A Simple and Mild Method for the cis-Hydroxylation of Alkenes with Cetyltrimethylammonium Permanganate” SYNTHESIS, no. 5, 1984, pages 431-433, XP002581198
2	*	BROOKS P R ET AL: “Synthesis of 2,3,4,5-tetrahydro-1,5-methano-1H-3-benzaz epine via oxidative cleavage and reductive amination strategies” SYNTHESIS 20040803 DE, no. 11, 3 August 2004 (2004-08-03), pages 1755-1758, XP002581197 ISSN: 0039-7881
3	*	SORBERA L A ET AL: “Varenicline tartrate: Aid to smoking cessation nicotinic [alpha]4[beta]2 partial agonist” DRUGS OF THE FUTURE 200602 ES LNKD- DOI:10.1358/DOF.2006.031.02.964028, vol. 31, no. 2, February 2006 (2006-02), pages 117-122, XP002581199 ISSN: 0377-8282 DOI: 10.1358/dof.2006.031.02.964028

WO2001062736A1 *	Feb 8, 2001	Aug 30, 2001	Pfizer Products Inc.	Aryl fused azapolycyclic compounds
WO2002085843A2 *	Mar 4, 2002	Oct 31, 2002	Pfizer Products Inc.	Process for the preparation of 1,3-substituted indenes and aryl-fused azapolycyclic compounds
WO2006090236A1 *	Feb 21, 2006	Aug 31, 2006	Pfizer Products Inc.	Preparation of high purity substituted quinoxaline
WO2008060487A2 *	Nov 9, 2007	May 22, 2008	Pfizer Products Inc.	Polymorphs of nicotinic intermediates

Reference
1	*	COE J W ET AL: “Varenicline: an alpha4beta2 Nicotinic Receptor Partial Agonist for Smoking Cessation” JOURNAL OF MEDICINAL CHEMISTRY, AMERICAN CHEMICAL SOCIETY, WASHINGTON., US, vol. 48, no. 10, 1 January 2005 (2005-01-01), pages 3474-3477, XP002474642 ISSN: 0022-2623 cited in the application

Citing Patent	Filing date	Publication date	Applicant	Title
WO2010005643A1 *	May 28, 2009	Jan 14, 2010	Teva Pharmaceutical Industries Ltd.	Processes for purifying varenicline l-tartrate salt and preparing crystalline forms of varenicline l-tartrate salt
WO2011110954A1 *	Mar 8, 2011	Sep 15, 2011	Actavis Group Ptc Ehf	Highly pure varenicline or a pharmaceutically acceptable salt thereof substantially free of methylvarenicline impurity
WO2011154586A3 *	Jun 13, 2011	Mar 22, 2012	Medichem, S. A.	Improved methods for the preparation of quinoxaline derivatives
EP2581375A2 *	Jun 13, 2011	Apr 17, 2013	Medichem, S.A.	Improved methods for the preparation of quinoxaline derivatives
US8039620	May 21, 2009	Oct 18, 2011	Teva Pharmaceutical Industries Ltd.	Varenicline tosylate, an intermediate in the preparation process of varenicline L-tartrate
US8178537	Jun 22, 2010	May 15, 2012	Teva Pharmaceutical Industries Ltd.	Solid state forms of varenicline salts and processes for preparation thereof

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External links

Manufacturer’s website USA

Varenicline
Systematic (IUPAC) name


7,8,9,10-Tetrahydro-6,10-methano-6H-pyrazino[2,3-h] [3]benzazepine
Clinical data
Trade names	Chantix
AHFS/Drugs.com	Monograph
MedlinePlus	a606024
License data	EU EMA: Champix US FDA: Varenicline
Pregnancy category	AU: B3 US: C (Risk not ruled out)
Routes of administration	Oral
Legal status
Legal status	AU: S4 (Prescription only) CA: ℞-only UK: POM (Prescription only) US: ℞-only
Pharmacokinetic data
Protein binding	<20%
Metabolism	Limited (<10%)
Biological half-life	24 hours
Excretion	Renal (81–92%)
Identifiers
CAS Number	249296-44-4 375815-87-5
ATC code	N07BA03 (WHO)
PubChem	CID 5310966
IUPHAR/BPS	5459
DrugBank	DB01273
ChemSpider	4470510
UNII	W6HS99O8ZO
KEGG	D08669
ChEBI	CHEBI:84500
ChEMBL	CHEMBL1076903
Chemical data
Formula	C₁₃H₁₃N₃
Molar mass	211.267 g/mol

////////////Varenicline, Chantix™, FDA 2006, 249296-44-4, 375815-87-5, Champix , Pfizer, バレニクリン酒石酸塩

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Written Confirmation expired: Can an API still be imported when produced earlier?

regulatory Comments Off

Jul 282016

What needs to be considered if an API is produced in the time period of a valid written confirmation but imported after this confirmation has expired? This is answered in a revised Q&A Document of the EU Commission.

see………http://www.gmp-compliance.org/enews_05432_Written-Confirmation-expired-Can-an-API-still-be-imported-when-produced-earlier_15432,15354,15367,Z-QAMAP_n.html

The EU Commission has updated its Question and Answers Document “Importation of active substances for medicinal products for human use” (now version 7). In this updated version, the question “Can an API batch manufactured during the period of validity of a written confirmation be imported into the EU once the written confirmation is expired?”

In the answer it is referred to Article 46(b)(2)(b) of Directive 2001/83/EC, where it is defined that APIs can only be imported if they are manufactured in accordance with EU GMP or equivalent, and accompanied by a written confirmation from the competent authority of the exporting third country certifying this.

But what if an API is produced in the time period of a valid written confirmation but imported after this confirmation has expired?

In the respective answer the EU Commission states that “it is legitimate to consider that the guarantees of equivalence provided by the written confirmation apply to any API batch in the scope of the written confirmation which was released for sale within the period of validity of the written confirmation, even if not exported in that time period.”

So the answer is ‘yes’, it still can be imported. But it needs to be accompanied by the expired written confirmation together with appropriate documentation which proves “that the whole consignment has been manufactured and released for sale by the quality unit before the expiry date of the written confirmation” and “provides a solid justification of why a valid written confirmation is not available.”

An import without any written confirmation is not possible.

///////////API, produced, time period of a valid written confirmation, imported, confirmation has expired, revised Q&A Document of the EU Commission.