Quinazoline, Pyrazolo[1,5-c]Quinazoline and Spiro Quinazoline Dimers from the Reaction of 2-Aminoacetophenone Hydrazones with Triphosgene

The reaction of hydrazones of 2-aminoacetophenone with triphosgene in dichloromethane or benzene in the presence of triethylamine gave quinazolines, pyrazolo[1,5-c]quinazoline and spiro quinazoline dimers. The latter compounds are being reported for the first time. In addition, a 4,4-disubstituted quinazoline derivative is prepared and its x-ray crystal structure is reported.