Condensation of 2-[(E)-pent-3-en-2-yl]-4-, 2[(E)-pent-2-en-2-yl]-4-, or 2-(
cyclopent-1-enyl)-6-methylaniline with 1-chloro-1-(N-mecthylimino)- or 1-ch
loro-1-(N-phenyl-imino)ethane affords the corresponding amidines. Cyclizati
on of the N-methylimino derivatives in polyphosphoric acid gives 3,4-dihydr
oquinazolines in high yields.