Studies with aza-heterocyclic N-oxides: Synthesis of some new aromatic N-oxide derivatives

Abstract

A benzofuroxan deriv. reacts with cyanoacetanilide derivs. to give benzimidazole compds. Benzofuroxan reacts with rhodanine derivs. in the presence of sodium ethoxide to give (arylamino)benzoimidazole derivs. The last reaction afforded thiazolidinone derivs. and benzoquinonedioxime derivs. when it was repeated in the presence of sodium acetate. Moreover, several quinoxalinyl 1,4-di-N-oxide derivs. were prepd. starting from quinoxaline 1,4-di-N-oxide derivs. A plausible reaction mechanism accounting for the formation of products was discussed. The synthesis of the target compds. was achieved using 5-methyl-2,1,3-benzoxazidazole 1-oxide (5-methylbenzofuroxan) and 2,1,3-benzoxazidazole 1-oxide (benzofuroxan) as starting materials. Example compds. thus prepd. included 1-hydroxy 1H-benzimidazole-2-acetamide 3-oxide (I) and a quinoxaline 1,4-dioxide deriv. (II). [on SciFinder(R)]