Thermolysis of polyazapentadienes. Part 7. An unambiguous route to 7-substituted quinolines from cinnamaldehyde derivatives

Abstract

Flash vacuum pyrolysis of the cinnamaldehyde phenylhydrazone derivatives (4)–(6) or O-alkyl oxime derivatives (7)–(12) at 600–650 °C and 10^–2–10^–3 Torr leads to approximately equal quantities of cinnamonitriles and quinolines. Use of a p-substituted cinnamaldehyde derivative gives the appropriate 7-substituted quinoline in high isomeric purity; the reactions take place via conjugated iminyl radicals.