Reaction of 4-arylmethylene-3-phenylisoxazolones and 4-arylmethylene-1,3-diphenylpyrazolones with enamines and nucleophilic heterocycles

Abstract

4-Arylmethylene-3-phenylisoxazolones (1) and 4-arylmethylene-1,3-diphenylpyrazolones (2) were treated with enamines (8), 3-phenylisoxazol-5(4H)-one (4), 1,3-diphenylpyrazol-5(4H)-one (6), and 2-phenyloxazol-5(4H)-one (3). The enamines were β-alkylated to give 1:1 adducts (9) and (10). The reaction of (1) with (6) and (2) with (4) gave symmetrical benzylidenedi-isoxazolones and -pyrazolones (7). 2-Phenyloxazol-5(4H)-one with (1) gave 4-benzylidene-2-phenyloxazolone (5) by transfer of the benzylidene group and with (2), a 1:1 adduct (19) isolated as the corresponding ethyl hippurate derivative (20).