Synthesis of alkenylquinolines and cyclization of (1-methyl-2-butenyl)quinaldines in polyphosphoric acid
The reaction of 2- and 4-alkenylanilines with paraldehyde gave 6- and 8-alkenylquinaldines. Heating 8-(1′-methyl-2′-butenyl)quinaldines in polyphosphoric acid leads to the formation of tricyclic compounds with isomerization of the alkenyl group.