phenacylester 1, were unsuccesfully tried as starting materials for the synthesis of N-amino-3-hydroxy-2-phenyl-4(1H)-quinolinone 8. The desired compound 8 was prepared by cyclization of N-acetyl as well as N-benzoyl-hydrazinobenzoic acid phenacylester 6a or 6b in polyphosphoric acid to afford N-acylamino-3-hydroxy-2-phenyl-4(1H)-quinolinone 7a or 7b, respectively. Surprisingly, the acyl group was resistant