Photolysis and thermolysis of N-(N-arylimidoyl)sulphimides

Abstract

Routes to the imidoylsulphimides (1) are described, starting from either the corresponding amidines or the imidoyl chlorides. Photolysis of the sulphimides involves cleavage of the sulphur–nitrogen bonds and gives 2-substituted benzimidazoles in good yields.

SS-Dimethyl-N-(N-phenylbenzimidoyl)sulphimide (1a) is decomposed by heating in benzonitrile or decalin under reflux, and gives 2-phenylbenzimidazole, 2-phenylquinazoline, and 2,4,6-triphenyl-1,3,5-triazine. Mechanisms are proposed for the formation of the last two, unexpected products. Similar thermal decomposition of the sulphimides (1b–e) is observed; the thermolysis is markedly catalysed by copper salts.