Intermediates Formed in the Reaction of Benzenethiol or<i>t</i>-Butylthiobenzene with Ethyl Benzoylacetate in Polyphosphoric Acid
作者:Hiroyuki Nakazumi、Shigeru Watanabe、Tohru Kitaguchi、Teijiro Kitao
DOI:10.1246/bcsj.63.847
日期:1990.3
The reaction of benzenethiol with ethyl benzoylacetate in polyphosphoric acid (PPA) at low temperature gave mainly ethyl 3-phenyl-3,3-bis(phenylthio)propionate 8 as an intermediate in the synthesis of thioflavones, while that from t-butylthiobenzene under similar conditions gave ethyl 3-(phenylthio)cinnamate 7 as a major product and many by-products. The reaction constant for intramolecular cyclic
苯硫醇与苯甲酰乙酸乙酯在多磷酸 (PPA) 中的低温反应主要得到 3-苯基-3,3-双(苯硫基)丙酸乙酯 8 作为合成硫黄酮的中间体,而在类似条件下由叔丁基硫苯合成条件得到 3-(苯硫基)肉桂酸乙酯 7 作为主要产物和许多副产物。使用哈米特取代基常数 σm 和 σm+,7 在 98% 硫酸中的分子内环缩合反应常数分别为 -0.46 和 -0.54。这表明 7 的苯硫醇部分的闭环位点处电子密度的增加促进了这种闭环反应。