反应详情

In accordance with yet another embodiment of the present invention, there is provided a process for producing (R)-(+)2-([3-methyl-4-(2,2,2-trifluoroethoxy)pyridin-2-yl]methylsulfinyl)-1H-benzimidazole comprising reacting 4-chloro-2,3-dimethyl-pyridine-1-oxide with sodium methane thiolate to give 2,3-dimethyl-4-methylsulfanyl-pyridine-1-oxide followed by oxidation using a suitable oxidizing agent to obtain (4-methanesulfonyl-2,3-dimethyl-pyridine)-1-oxide, chlorinating the resultant in the presence of suitable chlorinating agent to obtain 2-chloromethyl-4-methanesulfonyl-3-methylpyridine, condensing the 2-chloromethyl-4-methanesulfonyl-3-methylpyridine in presence of a suitable base in a solvent, optionally in the presence of a phase transfer catalyst with 2-mercaptobenzimidazole to obtain 2-(4-methanesulfonyl-3-methyl-pyridine-2-ylmethylsulfonyl)-1-H-benzimidazole, stereoselective oxidation of the 2-(4-methanesulfonyl-3-methyl-pyridine-2-ylmethylsulfonyl)-1-H-benzimidazole using an optically active compound in presence of a metal catalyst and a suitable solvent to obtain (R)-2-(4-methanesulfonyl-3-methyl-pyridin-2-ylmethanesulfinyl)-1H-benzimidazole and subsequently reacting the (R)-2-(4-methanesulfonyl-3-methyl-pyridin-2-ylmethanesulfinyl)-1H-benzimidazole with trifluoroethanol to obtain the (R)-(+)2-([3-methyl-4-(2,2,2-trifluoroethoxy)pyridin-2-yl]methylsulfinyl)-1H-benzimidazole.