Synthesis of 4-benzoylamino-3-phenyl-(1,2H)pyrazoliden-5-one and protein-ogenic amino acid from 4-(substitutedmethylene)-2-phenyl-5-(4H)oxazolone derivatives

The reaction of oxazolone 1a with hydrazine hydrate at room temperature afforded new intermediate. 4-benzoylamino-3-phenyl-(1,2H)pyrazoliden-5-one 2,might reacts through Micheal addition and ring opening of the oxazolones 1a and 1b with sodium ethoxide afforded propenate ester derivatives 3.