Synthesis of 4-Pyrazolylmethylidene-2-Oxazoline and -2-Imidazoline Derivatives

4-Formyl-2-pyrazolin-5-ones (1a,b) is condensed with hippuricacid derivatives (2a,b) to give the corresponding pyrazolylmethylideneazalactones (3a-d). Aminolysis of oxazolones (3) with aromaticamines in boiling acetic acid afforded imidazolones (4a-l).Treatment of oxazolones (3) with benzene in the presence of AlCl3 afforded α-benzamidoacetophenone (5). Structural assignments of thenew products were based on elemental analysis and IR, 1H NMRspectral data.