A process of synthesis of 5-methoxy-2-[(4-methoxy- 3,5-dimethyl- 2-pyridyl)methyl]sulfinyl-1H-benzimidazole using ethyl acetate as a solvent

摘要

A process for preparing 5-methoxy-2-[(4-methoxy-3,5-dimethyl-2-pyridyl)methyl]-sulphinyl- 1H-benzimidazole (omeprazole) of the formula (I) by reacting 5-methoxy-2-[(4-methoxy-3,5-dimethyl-2-pyridyl)methyl]-thio-1H-benzimidazole with 3-chloroperoxybenzoic acid in ethyl acetate at a temperature between -10oC and 5oC. The product is purified by dissolution in an aqueous solution of methylamine, by precipitation under addition of hydrochloric acid of up to pH 7-8 and isolation of the title compound in a pure form.