Dinitrones from C-benzyl nitrones

Abstract

N,N′-Dialkyl- and diaryl-dinitrones of the 2,3-diphenylbutanediylidenebisamine N,N′-dioxide (3) are shown to be intermediates in the spontaneous conversion of C-benzyl nitrones (1) into the diphenylpyrroles (4) or 2,3-diphenyl-prop-2-en-1-al (5). The process therefore involves oxidative coupling at the benzylic carbon atoms. The di-nitrones (3) have in fact been isolated on treatment of the nitrones (1) or their cyclic dimers (2) with oxygen. The N,N′-dialkyl dinitrones (3a) and (3b) gave the expected bis-cycloadducts (6) on treatment with dimethyl acetylenedicarboxylate.