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Delamanid

Otsuka Pharmaceutical Co has been given the green light to sell its tuberculosis drug Deltyba in Europe.

Read more at: http://www.pharmatimes.com/Article/14-04-30/Otsuka_multi-drug_resistant_TB_drug_approved_in_Europe.aspx#ixzz30Sz3wf2k
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http://newdrugapprovals.org/2014/03/26/delamanid-an-experimental-drug-for-the-treatment-of-multi-drug-resistant-tuberculosis/

Delamanid

http://www.ama-assn.org/resources/doc/usan/delamanid.pdf

(2R)-2-Methyl-6-nitro-2-[(4-{4-[4-(trifluoromethoxy)phenoxy]-1-piperidinyl}phenoxy)methyl]-2,3-dihydroimidazo[2,1-b][1,3]oxazole

2(R)-Methyl-6-nitro-2-[4-[4-[4-(trifluoromethoxy)phenoxy]piperidin-1-yl]phenoxymethyl]-2,3-dihydroimidazo[2,1-b]oxazole

(R) -2-methyl-6-nitro-2- { 4- [4- (4- trifluoromethoxyphenoxy) piperidin-l-yl] phenoxymethyl } -2 , 3- dihydroimidazo [2 , 1-b] oxazole

Imidazo[2,1-b]oxazole, 2,3-dihydro-2-methyl-6-nitro-2-[[4-[4-[4-(trifluoromethoxy)phenoxy]-1-piperidinyl]phenoxy]methyl]-, (2R)-

(R)-2-methyl-6-nitro-2-{4-[4-(4-trifluoromethoxyphenoxy)piperidin-1-yl]phenoxymethyl}-2,3-dihydroimidazo[2,1-b]oxazole

681492-22-8 cas no

Delamanid (USAN, codenamed OPC-67683) is an experimental drug for the treatment of multi-drug-resistant tuberculosis. It works by blocking the synthesis of mycolic acids in Mycobacterium tuberculosis, the organism which causes tuberculosis, thus destabilising its cell wall.[1][2][3]

In phase II clinical trials, the drug was used in combination with standard treatments, such as four or five of the drugs ethambutol, isoniazid,pyrazinamide, rifampicin, aminoglycoside antibiotics, and quinolones. Healing rates (measured as sputum culture conversion) were significantly better in patients who additionally took delamanid.[3][4]

The European Medicines Agency (EMA) recommended conditional marketing authorization for delamanid in adults with multidrug-resistant pulmonary tuberculosis without other treatment options because of resistance or tolerability. The EMA considered the data show that the benefits of delamanid outweigh the risks, but that additional studies were needed on the long-term effectiveness.[5]

Delamanid, an antibiotic active against Mycobacterium tuberculosis strains, has been filed for approval in the E.U. and by Otsuka for the treatment of multidrug-resistant tuberculosis. In 2013, a positive opinion was received in the E.U. for this indication. Phase III trials for treatment of multidrug-resistant tuberculosis are under way in the U.S. Phase II study for the pediatric use is undergone in the Europe.

The drug candidate’s antimycobacterial mechanism of action is via specific inhibition of the synthesis pathway of mycolic acid, which is a cell wall component unique to M. tuberculosis.

In 2008, orphan drug designation was received in Japan for the treatment of pulmonary tuberculosis.

Tuberculosis (TB), an airborne lung infection, still remains a major public health problem worldwide. It is estimated that about 32% of the world population is infected with TB bacillus, and of those, approximately 8.9 million people develop active TB and 1.7 million die as a result annually according to 2004 figures. Human immunodeficiency virus (HIV) infection has been a major contributing factor in the current resurgence of TB. HIV-associated TB is widespread, especially in sub-Saharan Africa, and such an infectious process may further accelerate the resurgence of TB.

Moreover, the recent emergence of multidrug-resistant (MDR) strains ofMycobacterium tuberculosis that are resistant to two major effective drugs, isonicotinic acid hydrazide (INH) and rifampicin (RFP), has further complicated the world situation.

The World Health Organization (WHO) has estimated that if the present conditions remain unchanged, more than 30 million lives will be claimed by TB between 2000 and 2020. As for subsequent drug development, not a single new effective compound has been launched as an antituberculosis agent since the introduction of RFP in 1965, despite the great advances that have been made in drug development technologies.

Although many effective vaccine candidates have been developed, more potent vaccines will not become immediately available. The current therapy consists of an intensive phase with four drugs, INH, RFP, pyrazinamide (PZA), and streptomycin (SM) or ethambutol (EB), administered for 2 months followed by a continuous phase with INH and RFP for 4 months. Thus, there exists an urgent need for the development of potent new antituberculosis agents with low-toxicity profiles that are effective against both drug-susceptible and drug-resistant strains of M. tuberculosis and that are capable of shortening the current duration of therapy.

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US20060094767

(R)-2-bromo-4-nitro-1-(2-methyl-2-oxiranylmethyl)imidazole

4-[4-(4-Trifluoromethoxyphenoxy)piperidin-1-yl]phenol

ARE THE INTERMEDIATES

Example 1884

Production of (R)-2-methyl-6-nitro-2-{4-[4-(4-trifluoromethoxyphenoxy)piperidin-1-yl]phenoxymethyl}-2,3-dihydroimidazo[2,1-b]oxazole

4-[4-(4-Trifluoromethoxyphenoxy)piperidin-1-yl]phenol (693 mg, 1.96 mmol) was dissolved in N,N′-dimethylformamide (3 ml), and sodium hydride (86 mg, 2.16 mmol) was added while cooling on ice followed by stirring at 70-75° C. for 20 minutes. The mixture was cooled on ice. To the solution, a solution prepared by dissolving (R)-2-bromo-4-nitro-1-(2-methyl-2-oxiranylmethyl)imidazole (720 mg, 2.75 mmol) in N,N′-dimethylformamide (3 ml) was added followed by stirring at 70-75° C. for 20 minutes. The reaction mixture was allowed to return to room temperature, ice water (25 ml) was added, and the resultant solution was extracted with methylene chloride (50 ml) three times. The organic phases were combined, washed with water 3 times, and dried over magnesium sulfate. After filtration, the filtrate was concentrated, and the residue was purified by silica gel column chromatography (methylene chloride/ethyl acetate=3/1). Recrystallization from ethyl acetate/isopropyl ether gave (R)-2-methyl-6-nitro-2-{4-[4-(4-trifluoromethoxyphenoxy)piperidin-1-yl]phenoxymethyl}-2,3-dihydroimidazo[2,1-b]oxazole (343 mg, 33%) as a light yellow powder.

…………………………

WO 2010021409 AND http://worldwide.espacenet.com/publicationDetails/biblio?CC=IN&NR=203704A1&KC=A1&FT=D

FOR 2, 4 DINITROIMIDAZOLE

…………………………………………

WO2011093529A1

These patent literatures disclose Reaction Schemes A and B below as the processes for producing the aforementioned 2, 3-dihydroimidazo [2, 1-b] oxazole compound.

Reaction Scheme A:

wherein R1 is a hydrogen atom or lower-alkyl group; R2 is a substituted pxperidyl group or a substituted piperazinyl group; and X1 is a halogen atom or a nitro group.

Reaction Scheme B:

wherein X2 is a halogen or a group causing a substitution reaction similar to that of a halogen; n is an integer from 1 to 6; and R1, R2 and X1 are the same as in Reaction Scheme A.

An oxazole com ound represented by Formula (la) :

, i.e., 2-methyl-6-nitro-2-{4- [4- (4- trifluoromethoxyphenoxy) piperidin-l-yl] phenoxymethyl }-2, 3- dihydroimidazo [2, 1-b] oxazole (hereunder, this compound may be simply referred to as “Compound la”) is produced, for example, by the method shown in the Reaction Scheme C below (Patent

Literature 3) . In this specification, the term “oxazole compound’ means an oxazole derivative that encompasses compounds that contain an oxazole ring or an oxazoline ring (dihydrooxazole ring) in the molecule.

Reaction Scheme C:

However, the aforementioned methods are unsatisfactory in terms of the yield of the objective compound. For example, the method of Reaction Scheme C allows the objective oxazole Compound (la) to be obtained from Compound (2a) at a yield as low as 35.9%. Therefore, alternative methods for producing the compound in an industrially advantageous manner are desired. Citation List

Patent Literature

PTL 1: WO2004/033463

PTL 2: WO2004/035547

PTL 3: WO2008/140090

Example 9

Production of (R) -2-methyl-6-nitro-2- { 4- [4- (4- trifluoromethoxyphenoxy) piperidin-l-yl] phenoxymethyl } -2 , 3- dihydroimidazo [2 , 1-b] oxazole

{R) -1- [ – {2 , 3-epoxy-2-methylpropoxy ) phenyl] -4- [4- ( trifluoromethoxy ) phenoxy ] piperidine (10.0 g, 23.6 mmol, optical purity of 94.3%ee), 2-chloro-4-nitroimidazole (4.0 g, 27.2 mmol), sodium acetate (0.4 g, 4.9 mmol), and t- butyl acetate (10 ml) were mixed and stirred at 100°C for 3.5 hours. Methanol (70 ml) was added to the reaction mixture, and then a 25% sodium hydroxide aqueous solution (6.3 g, 39.4 mmol) was added thereto dropwise while cooling with ice. The resulting mixture was stirred at 0°C for 1.5 hours, and further stirred at approximately room

temperature for 40 minutes. Water (15 ml) and ethyl acetate (5 ml) were added thereto, and the mixture was stirred at 45 to 55°C for 1 hour. The mixture was cooled to room temperature, and the precipitated crystals were collected by filtration. The precipitated crystals were subsequently washed with methanol (30 ml) and water (40 ml) . Methanol (100 ml) was added to the resulting

crystals, followed by stirring under reflux for 30 minutes. The mixture was cooled to room temperature. The crystals were then collected by filtration and washed with methanol (30 ml) . The resulting crystals were dried under reduced pressure, obtaining 9.3 g of the objective product (yield: 73%) .

Optical purity: 99.4%ee.

……………….

Synthesis and antituberculosis activity of a novel series of optically active 6-nitro-2,3-dihydroimidazo[2,1-b]oxazoles
J Med Chem 2006, 49(26): 7854

http://pubs.acs.org/doi/abs/10.1021/jm060957y

(R)-2-Methyl-6-nitro-2-{4-[4-(4-trifluoromethoxyphenoxy)piperidin-1-yl]phenoxymethyl}-2,3-dihydroimidazo[2,1-b]oxazole (19,  DELAMANID).

To a mixture of 27 (127.56 g, 586.56 mmol) and 4-[4-(4-trifluoromethoxyphenoxy)piperidin-1-yl]phenol (28g) (165.70 g, 468.95 mmol) in N,N-dimethylformamide (1600 mL) was added 60% sodium hydride (22.51 g, 562.74 mmol) at 0 °C portionwise. After the mixture was stirred at 50 °C for 2 h under a nitrogen atmosphere, the reaction mixture was cooled in an ice bath and carefully quenched with ethyl acetate (230 mL) and ice water (50 mL). The thus-obtained mixture was poured into water (3000 mL) and stirred for 30 min. The resulting precipitates were collected by filtration, washed with water, and dried at 60 °C overnight. This crude product was purified by silica gel column chromatography using a dichloromethane and ethyl acetate mixture (5/1) as solvent. The appropriate fractions were combined and evaporated under reduced pressure. The residue was recrystallized from ethyl acetate (1300 mL)−isopropyl alcohol (150 mL) to afford 19 (119.11 g, 48%) as a pale yellow crystalline powder.

Mp 195−196 °C.

1H NMR (CDCl3) δ 1.77 (3H, s), 1.87−2.16 (4H, m), 2.95−3.05 (2H, m), 3.32−3.41 (2H, m), 4.02 (1H, d, J = 10.2 Hz), 4.04 (1H, d, J = 10.2 Hz), 4.18 (1H, J = 10.2 Hz), 4.36−4.45 (1H, m), 4.49 (1H, d, J = 10.2 Hz), 6.76 (2H, d, J = 6.7 Hz), 6.87−6.94 (4H, m), 7.14 (2H, d, J = 8.6 Hz), 7.55 (1H, s).

[α  −9.9° (c 1.01, CHCl3).

MS (DI) m/z 535 (M+ + 1). Anal. (C25H25F3N4O6) C, H, N.

http://pubs.acs.org/doi/suppl/10.1021/jm060957y/suppl_file/jm060957ysi20061113_095044.pdf

References

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