cine-Substitution in methoxydehalogenation of some halogenobenzofurazans

Abstract

Through investigation of the reaction of 4- and 5-iodobenzofurazan with sodium methoxide in methanol a new mechanism is proposed, in addition to the S_NAr-type pathway previously reported, for the methoxydehalogenation of halogenobenzofurazans. This novel pathway, which is responsible for the ‘cine-substitution,’ seems to be an ‘elimination–addition’ rather than an ‘addition–elimination’ anomalous-type mechanism (AE_a). However, some competition by the AE_a mechanism is not excluded.