SULFUR-CONTAINING BENZIMIDAZOLE DERIVATIVES, PROCESS FOR THE PREPARATION THEREOF AND INTERMEDIATES USEFUL IN PRODUCTION OF THE SAME

摘要

This invention relates to a process for the preparation of 5(6)thio-benzimidazole derivatives of the formula I and salts thereof (I) (wherein R1 is hydrogen or a group of the formula -COOR5; R5 is C1-4 alkyl; R2 is hydrogen, halogen, C1-6 alkyl, trifluoromethyl or a group of the formula -OR3; R3 is C1-4 alkyl, aryl or aralkyl; R4 stands for hydrogen, C1-6 alkyl, C3-7 cycloalkyl, C3-6 alkenyl, C3-6 alkynyl, or an aryl or aralkyl group whereby the aryl ring of the aryl or aralkyl group may be optionally substituted by one or more halogeno, C1-4 alkyl, nitro, hydroxy, C1-4 alkoxy, C1-4 alkylthio, carboxy or cyano substituent(s) or a group of the formula -S(O)n-R8 in which R8 is lower alkyl; n stands for 0, 1 or 2) which comprises subjecting a compound of the Formula VI (VI) to reduction (wherein R1 and R2 are as stated above) and if desired introducing an R4 group being other than hydrogen into the compound of the Formula I thus formed (wherein R1 and R2 are as stated above and R4 is hydrogen) and if desired converting a compound of the Formula I thus obtained into its salt.