METHOD FOR OBTAINING DERIVATIVES OF [[(PYRIDIL SUBSTITUTED)METHYL]THIO]BENZIMIDAZOLE

The method for obtaining derivatives of [[(pyridil substituted) methyl]thio]benzimidazole (I), where each of R1, R3 and R4, independently of each other, is hydrogen, an alkyl, alkoxy or fluorinated alkoxy of 1 to 6 carbon atoms, and R2 is nitro, halogen, alkoxy or halogenated alkoxy of 1 to 6 carbon atoms, or a group -O-(CH2)n-OR8, where n is an integer between 1 and 6 and R8 represents hydrogen or an alkyl group with 1 to 6 carbon atoms, which involves (a) reacting an N-oxide of a methylpyridine with an anhydride of activated carboxylic acid or of sulfonic acid, and (b) reacting the intermediate formed in stage (a) with a corresponding mercaptobenzimidazole. The compounds (I) are useful in the synthesis of derivatives of [[(pyridil substituted) methyl] sulfinyl]benzimidazole, such as omeprazol, lansoprazol, rabeprazol or pantoprazol. (see formula I)