Quinoxaline precursors of fungitoxic benzimidazolylcarbamates: syntheses and photochemically-induced transformations

Abstract

Some quinoxalin-2-ylcarbamate N-oxides have been synthesised and shown to undergo photochemically-induced rearrangements, in a variety of solvents, to give benzimidazoles: methyl quinoxalin-2-ylcarbamate 1-oxide gave the fungicide, methyl benzimidazol-2-ylcarbamate. In contrast, irradiation under acidic conditions resulted in the formation of methyl 3-(2-isocyanophenyl)ureidocarboxylate.