Hydrogen Peroxide → Lansoprazole

Participants

Reaction Steps

2-[[3-Methyl-4-(2,2,2-trifluoroethoxy)pyrid-2-yl]methylthio]benzimidazole (monohydrate) (10.0 g) was dissolved in ethanol (75 ml), to which was added a solution of sodium metavanadate (15 mg) in 35% aqueous solution of hydrogen peroxide (3.07 g), and allowed to react by stirring at 20°-25° for about 8 hours. After completion of the reaction an aqueous solution of sodium thiosulfate (1 g/5 ml) was added to the reaction mixture, which was stirred vigorously for about 10 minutes. The crystals were collected by filtration and washed with an ice-cooled mixture of ethanol-water (1:1). The crystals thus obtained were treated with a mixture of ethanol-water (9:1, 50 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 (9.0 g). (yield: 90.5%).

Provenance & Evidence