The synthesis and chemistry of 4-aza-azulene.

Abstract

4-Aza-azulene and its 5-bromo and 6-methoxy derivatives have been efficiently synthesized by spray pyrolysis of 2-halogenoindan-1-yl azidoformates at 300 °C and l–2 mm pressure of nitrogen. Bromination of 4-aza-azulene gives 1-bromo, 3-bromo, and 1,3-dibromo derivatives. Attempts to nitrate, trifluoroacetylate, or acetylate were unsuccessful. Diethyl azodicarboxylate gave a mixture of 1- and 3-hydrazinedicarboxylates, also probably by electrophilic substitution. Dimethyl acetyl-enedicarboxylate (DMAD) reacted by initial attack at nitrogen to give three adducts. The structures of two of these have been solved, one being a 3: 1 adduct and the other the dimer of a 2: 1 adduct of DMAD with aza-azulene. The latter was subjected to an X-ray crystallographic study. The action of m-chloroperbenzoic acid yielded the aza-azulene N-oxide.