Substituent Effects in the Fischer Indolization of (2-Sulfonyloxyphenyl)hydrazones (Fischer Indolization and Related Compounds. XXX).
作者:Yasuoki MURAKAMI、Hiroshi YOKOO、Yuusaku YOKOYAMA、Toshiko WATANABE
DOI:10.1248/cpb.47.791
日期:——
The effects of a variety of additional substituents of ethyl pyruvate 2-(2-methanesulfonyloxy)phenylhydrazone (7) in Fischer indolization were examined, When the substituent was a methyl group at the 3-, 4-, or 5-position, the yields of normal 7-methanesulfonyloxyindoles depended upon the position. The hydrazones having a methyl group at the position nearer to the methanesulfonyloxy group tended to give normal 7-methanesulfonyloxyindole in a higher percentage to total indolic products. In a series of 4-substituted phenylthydrazones (7d, e, f), more electron-withdrawing substituents tended to give normal 7-methanesulfonyloxyindole in a higher percentage to total indolic products than electron-donating ones. A hydrazone with a strong electron-withdrawing subsitiuent at the 4-position (7f) underwent intramolecular aromatic nucleophilic substitution by the enehydrazine moiety to give the cinnoline derivative.
研究了丙酮酸乙酯 2-(2-甲磺酰氧基)苯基腙(7)的各种附加取代基在费舍尔吲哚化反应中的影响,当取代基为 3-、4-或 5-位的甲基时,正常 7-甲磺酰氧基吲哚的产量取决于位置。在靠近甲烷磺酰氧基的位置上具有甲基的酰肼往往能生成正常的 7-甲烷磺酰氧基吲哚,其生成量占吲哚类总产物的比例较高。在一系列 4-取代苯基肼(7d、e、f)中,与提供电子的取代基相比,提供更多电子的取代基倾向于生成正常的 7-甲烷磺酰氧基吲哚,在吲哚类总产物中所占的比例更高。在 4 位(7f)上具有强夺电子取代基的腙发生了分子内芳香亲核取代烯肼的反应,生成了噌啉衍生物。