Patent ID: 6245913
Filing Date: 2001-06-12
Classification: C07D

Abstract:
A process for the preparation of 5-methoxy-2-[(3,5-dimethyl-4-methoxy-2-pyridinyl)methylsulfinyl]-1H-benzim idazole comprising the following steps:a) oxidizing 3,5-Lutidine to 3,5-Lutidine-N-Oxide by hydrogen peroxide in acetic acid;b) reducing excess hydrogen peroxide with formaldehyde;c) nitrating 3,5-Lutidine-N-Oxide to give a nitro compound product;d) isolating the nitro compound product by filtration after neutralization of the nitration reaction mixture in the presence of water sufficient to dissolve the salts of neutralization;e) reacting the nitro compound with dimethyl sulfate in a first solvent to give a dimethyl sulfate adduct;f) reacting the dimethyl sulfate adduct with aqueous ammonium persulfate in alcohol to provide an hydroxymethyl compound;g) reacting the hydroxymethyl compound with SOCl.sub.2 to give a chloromethyl compound;h) coupling the chloromethyl compound with 5-methoxy-2-mercaptobenzimidazole in a haloalkane with an alkali metal hydroxide or alkaline metal hydroxide in the presence of a phase transfer catalyst to form a coupled product;i) nucleophilic substitution of NO.sub.2 on the 4-position of the coupled product to form a thioether compound;j) treating the thio ether or its hydrochloride salt in a solvent, cooled to a temperature of about 0 C. or less, with hydrogen peroxide in the presence of phthalic anhydride and an alkali base.