Flash-pyrolysis of 1-vinylbenzotriazoles

Abstract

1-Vinylbenzotriazoles give indoles on flash vacuum pyrolysis, but depending on the vinyl substituents side reactions leading to N-phenylketenimines or benzonitrile are observed. The latter process occurs with 1,2-disubstituted vinyl groups and an azatrimethylenemethane is suggested as an intermediate. Ketenimine formation is associated with vinyl groups bearing an α-hydrogen and is the only pathway observed for 1-(2-methylprop-1-enyl)benzotriazole which does not give 3,3-dimethyl-3H-indole.