Methanol → Omeprazole

Participants

Reaction Steps

Sodium perborate 4H2O (11.2 g, 73.0 mmol) was suspended in water (50 ml), followed by the dropwise addition of a solution of acetic anhydride (6.87 ml, 73.0 mmol)/methanol (5.75 ml) at 15.4° C. over 6 minutes and then, the mixture was stirred for about 13 min to prepare a homogenous solution (bulk temperature; 15.4° C. to 19.4° C.). The resulting solution was added dropwise to a solution (220 ml) of 5-methoxy-2-[(4-methoxy-3,5-dimethyl-2-pyridyl)methylthio]-1H-benzimidazole (20.0 g, 60.8 mmol) in toluene/methanol (10:1) at −20° C. over 2 hr. The resulting mixture was further stirred at the same temperature for 1 hr. The resulting crystals were collected by filtration, washed for three times with water (20 ml) and washed twice with tert-butyl methyl ether (20 ml). The resulting crystals were dried, to give the title compound (17.8 g, yield; 85.0%) as a white solid.

Provenance & Evidence