N-CHLOROSUCCINIMIDE/SODIUM HYDROXIDE-MEDIATED SYNTHESIS OF BENZIMIDAZOLES FROM AMIDINES UNDER MILD CONDITIONS

摘要

A convenient room-temperature one-pot procedure for the preparation of benzimidazoles derivatives from N-arylamidines has been developed. The reaction of N-aryl-N'-chloro amidines, generated by the treatment of N-aryl-amidines with N-chlorosuccinimide, in presence of sodium hydroxide provides benzimidazoles in good to excellent yields. Nitrogen anion generated in situ from succinimide (by-product of the chlorination step using NCS) and hydroxide anion was found to be highly effective as Br0nsted base to promote the cyclization into benzimidazole of N-aryl-N'-chloroamidine.