1-Azatriene cyclisation as a route to annelated pyrido[4,3-b]indoles

Article abstract of DOI:10.1016/S0040-4020(97)00117-8

Derivatives of indole-3-carbaldehyde oxime have been prepared that bear a carbon-carbon double bond at C-2 and a five- or six-membered ring linking the α-carbon atom of the vinyl group and the indole nitrogen atom. Compound 9, with a five-membered ring linking the two atoms, failed to undergo a cyclisation reaction on heating. However the oximes 16 and 22, with a six-membered ring linking the two atoms, cyclised in boiling toluene. The cyclisation led to the formation of the pyridoindoles 17 and 18, respectively.