Cinnolines. Part 1. Widman-Stoermer reactions of functionalised 2-phenylbut-2-enes to give cinnolinecarbaldehydes

Abstract

Diazotisation of a mixture of the E- and Z-isomers of 2-(2-aminophenyl)but-2-ene-1,4-diol gives 4-(hydroxymethyl)cinnoline-3-carbaldehyde, by spontaneous oxidation of the presumed intermediate, 3,4-bis(hydroxymethyl)cinnoline. Further oxidation of the reaction product gives cinnoline-3,4-dicarbaldehyde. Cyclisation reactions of other 2-(2-aminophenyl)but-2-ene derivatives, leading to quinolines and a benzisoxazine, are described.