m-Chloroperbenzoic acid → Lansoprazole

Participants

Reaction Steps

2-[[3-Methyl-4-(2,2,2-trifluoroethoxy)pyrid-2-yl]methylthio]benzimidazole (monohydrate) (20 g) was dissolved in chloroform (200 ml), to which was added slowly dropwise below 5° C. a solution of m-chloroperbenzoic acid (13.5 g) in chloroform (200 ml), and stirred at the same temperature for about 10 minutes. After completion of the reaction, the reaction mixture was washed with a solution of sodium hydrogencarbonate, and dried over magnesium sulfate, and chloroform was evaporated off under reduced pressure. To the residue was added ethanol (100 ml) for crystallization, which was ice-cooled; the resulting crystals were collected by filtration and washed with ice-cooled ethanol. The crystals thus obtained were treated with a mixture of ethanol-water (9:1, 90 ml), heated (65°-70° C.) and stirred so that the crystals were dissolved, then the insoluble matters were removed by hot filtration. The filtrate was ice-cooled for crystallization and the crystals were collected by filtration, washed with ice-cooled ethanol-water mixture (8:2), and dried in vacuo, to give white needles of 2-[[3-methyl-4-(2,2,2-trifluoroethoxy)pyrid-2-yl]methylsulfinyl]benzimidazole (14.9 g, yield: 74.9%).

Provenance & Evidence