Approach to polysubstituted 4-pyridones from N-aryl acetoacetamides via a N to C 1,3-acyl migration mediated by sodium persulfate.

Mediated by sodium persulfate (Na(2)S(2)O(8)), a series of polysubstituted 4-pyridones were synthesized via self-condensation of N-aryl acetoacetamides, during which a novel N to C 1,3-acyl migration should be involved. The structure of 4-pyridone was unequivocally confirmed by X-ray diffraction analysis. However, the self-condensation of N-benzyl acetoacetamides under the same condition gave polysubstituted 2-pyridones instead of 4-pyridones.