摘要：1-Methyl-3-acetyl-6-pyridone (VIII) was prepared. Though quaternary metho-salt of 3-acetylpyridine did not undergo smooth oxidation with alkaline ferricyanide, the corresponding ethylene-ketal (VIa) was oxidized smoothly, giving 1-methyl-3-acetyl-6-pyridone ethylene-ketal (VIIa) in ca.85% yield. The latter was hydrolyzed in dilute acid to give 3-acetyl compound (VIII) in quantitative yield. Huang-Minlon reduction converted the latter into 1-methyl-3-ethyl-6-pyridone (X) in a fair yield, from which the corresponding piperidone (XI) was obtained by catalytic hydrogenation over Raney nickel. Wolfrom and Karabinos method applied to di(ethylthio) compound (XIII) of (VIII) gave a mixture of (X) and (XI), of which the latter was formed predominantly. For the direct synthesis of (XI), oxidation of ethylenedithio compound of 1-methyl-3-acetyl-pyridi nium salt (VIb) was preferred to furnish the corresponding 6-pyridone (VIIb), which was directly desulfurized according to the method of Wolfrom and Karabinos to yield(XI).
