Comparative Studies on the Behavior of 3-Amino-2-phenyl-4(3<Emphasis Type="Italic">H</Emphasis>)-quinazolinone Towards Some Organophosphorus Reagents

Summary. The reaction of 3-amino-2-phenyl-4(3H)-quinazolinone with oxovinylidenetriphenylphosphorane afforded 5-phenylpyrazolo1,5-c] quinazoline-2(3H)-one and triphenylphosphine oxide. On the other hand, when quinazolinone reacts with phosphorus ylides, the corresponding phosphorane adducts were obtained. Moreover, quinazolinone reacts with trisdialkylaminophosphines to give the new (dialkylamino)oxophosphonium dipolar products. Possible reaction mechanisms are considered and the structural assignments are based on analytical and spectroscopic results.