Reaction of 2-(4'-thiazolyl)benzimidazole (thiabendazole) with alkyl halides

Abstract

2-(4'-Thiazolyl)benzimidazole (thiabendazole) is alkylated at a benzimidazole nitrogen by reaction with sodium hydride and an alkyl halide. With 1, 3-dibromo-propane and 1, 2-dibromoethane, the thiazole nitrogen is also alkylated to give quaternary salts containing the 6, 7-dihydro-5H-thiazolo[3', 4':1, 2][1, 4]diazepino-[8, 9-a]benzimidazole and 5, 6-dihydrothiazolo[3', 4':1, 2]pyrazino[7, 8-a]benzimidazole ring systems respectively. The structures proposed for these tetracyclic products are supported by spectroscopic examination of the products formed by alkali fission of their thiazole rings. © 1971 CSIRO. All rights reserved.