Solid phase synthesis of 1-alkyl-2-alkylthio-5-carbamoylbenzimidazoles

Abstract The preparation of 1-alkyl-2-alkylthio-5-carbamoylbenzimidazoles 7 is described. The cyclization of a resin bound o -phenylenediamine 4 with thiocarbonyldiimidazole (TCD) in THF provided a benzimidazole-2-thione 5 . Treatment of 5 with benzylic halides in the presence of DIEA resulted in the resin bound 1-alkyl-2-alkylthio-5-carbamoylbenzimidazoles 6 . The final products were cleaved from the resin and obtained in from 74% to 99% yields.