Synthesis of some new pyrazoloquinazolinone and quinazolinone derivatives

摘要

The benzoxazinone derivative 2-(6,8-dibromo-4-oxo-4H-benzo[d]-1,3-oxazin-2-yl)-3-(4-methoxyphenyl)acrylonitrile (1) has been used as a starting material for preparation of the hitherto unknown pyrazoloquinazolinone and quinazolinone derivatives. Under different conditions the benzoxazinone (1) was reacted with hydrazine hydrate to provide the pyrazolocarbonitrile derivative (2) and the azine derivative (3) and/or the pyrazoloquinazoline derivative (4). When (4) was conducted to react either with EAA (ethyl acetoacetate) or Ac2O/AcOH (acetic anhydride/acetic acid) mixture or phthalic anhydride/acetic acid mixture, the pyrazoloquinazoline carbonitrile (5), pyrazolo-quinazoline acetic acid (6) or the pyrazoloquinazolinone derivative (7) were formed respectively. When (1) was reacted with phenylhydrazine, a mixture of the quinazolinone derivative (8) and the hydrazone derivative (9) were obtained. The benzoxazinone derivative (1) was found also to react with benzylamine in ethanol or without solvent to give the quinazolinone derivative (10) or the quinazolindione (11) respectively. Fusion of (1) with ammonium acetate yielded the quinazolinone (12), which was methylated to give (13) and thiated to the thioxyquinazoline derivative (14), while reaction of (1) with formamide gave the N-formylquinazoline derivative (15).