Lactams. X. The alkaline ferricyanide oxidation of 3-substituted 1-(3,4-dimethoxyphenethyl)pyridinium salts: Effects of functional substituents.
作者:TOZO FUJII、MASASHI OHBA、SHIGEYUKI YOSHIFUJI、MAKOTO KIRISAWA
DOI:10.1248/cpb.25.2887
日期:——
In the alkaline ferricyanide oxidation at 32°of 3-substituted 1-(3, 4-dimethoxyphenethyl) pyridinium bromides (type 3), the hydroxymethyl, N, N-dimethylaminomethyl, carbamoyl, and 1, 1-ethylenedithioethyl groups at the 3-position have been found to orient the oxidation to both the 2-(type 4) and the 6-position (type 5) in ratios of 70 : 30, 26 : 74, 50 : 50, and 4 : 96. The carboxyl or 1, 1-ethylenedioxyethyl group at the 3-position has oriented the oxidation to the 6-position exclusively, and possible factors in determining the regioselectivity in the ferricyanide oxidation of the 1, 3-disubstituted pyridinium salts are discussed. For preparation of additional pyridone derivatives, 1-(3, 4-dimethoxyphenethyl)-5-carboxy-2(1H)-pyridone (5d) was esterified with methanolic hydrogen chloride to the methyl ester (5h), and 1-(3, 4-dimethoxyphenethyl)-5-(1, 1-ethylenedioxyethyl)-2 (1H)-pyridone (5e) was converted into the methyl ketone (5i) by acid hydrolysis. The structures of the pyridones (4a, b, c, f, 5a-i) thus prepared have assigned on the basis of their ultraviolet, infrared, and nuclear magnetic resonance spectra.
在 3-取代的 1-(3,4-二甲氧基苯乙基)吡啶鎓溴化物(类型 3)的 32°碱性铁氰氧化反应中,发现 3-位上的羟甲基、N,N-二甲氨基甲基、氨基甲酰基和 1,1-亚乙基二硫代乙基可将氧化定向到 2-位(类型 4)和 6-位(类型 5),比例分别为 70:30、26:74、50:50 和 4:96。3 位上的羧基或 1,1-亚乙二氧基乙基只将氧化作用定向到 6 位,讨论了决定 1,3-二取代吡啶鎓盐铁氰化物氧化作用区域选择性的可能因素。为了制备更多的吡啶酮衍生物,1-(3, 4-二甲氧基苯乙基)-5-羧基-2(1H)-吡啶酮(5d)被甲醇氯化氢酯化为甲基酯(5h),1-(3, 4-二甲氧基苯乙基)-5-(1, 1-亚乙二氧基乙基)-2(1H)-吡啶酮(5e)通过酸水解转化为甲基酮(5i)。根据紫外光谱、红外光谱和核磁共振光谱,确定了由此制备的吡啶酮(4a、b、c、f、5a-i)的结构。