抄録
The alkaline ferricyanide oxidation of the quaternary pyridinium salts (Ia-g) furnished pairs of the isomeric 2-pyridones (IIa-g) and 6-pyridones (IIIa-g) in good total yields. In all cases, the oxidation at the 2-position was much favored over that at the 6-position. The effect of the aryl group in the N-aralkyl chain on the orientation of the oxidation seemed to be negligibly small regardless of the number of the methylene groups separating the aryl group from the nitrogen. The extent of the 6-oxidation was slightly increased as the alkyl group at the 3-position was changed from the methyl to the ethyl group. The nuclear magnetic resonance spectra of these pyridones were measured in deuteriochloroform, carbon tetrachloride, and benzene-d6. On the basis of the results summarized in Tables III-VI, the effects of the aryl group and the number of the methylene groups in the N-substituent on the chemical shifts for the pyridone-ring and neighboring group protons are discussed.
