Synthesis of a novel ring-expanded nucleoside analogue containing the imidazo[4,5-e][1,3]diazepine ring system with a guanidinocarbamoyl-substituted cyclopropylidene group in place of a sugar moiety

Abstract

The synthesis of a novel ring-expanded nucleoside analogue, (Z)-1-((2-Guanidinocarbamoyl-cyclopropylidene)methyl)-4,5,7,8-tetrahydro-6H-6-iminoimidazo[4,5-e][1,3]diazepine-4,8-dione (1) has been reported. It was prepared starting from methyl imidazole-4,5-dicarboxylate by sequential condensations with 2-bromo-2-bromomethylcyclopropane-1-carboxylate and guanidine. The overall yield for the two-step synthesis is 46%.