The reaction of 2-(2-cyclopentenyl)anilines with I-2 in the presence of NaHCO3 results in formation of 3-iodocyclopenta[b]indoles in high yields. Under similar conditions 2-(2-cyclohexenyl)anilines give rise to cyclization products whose structure depends on the solvent and substituents in the aromatic ring and on the nitrogen atom.
N-Acetyl- and N-formyl-ortho-alkenyl(cycloalkenyl)anilines were synthesized. Their reaction with P2O5 or PCl5 afforded quinolines. By reaction of the ortho-alkenyl(cycloalkenyl)anilines with 1-methylimino- or 1-phenylimino-1-chloroethanes amidines were obtained that were cyclized in the polyphosphoric acid. The reaction with the polyphosphoric acid of amidines prepared from alkenylanilines and 1-methylimino-1-chloroethane gave rise to 3-methyl-3,4-dihydroquinazolines; on replacing in the substrate methylimine group for phenylimine one the yield of quinazoline decreased.