Reactions of Keto–Enol Tautomers of 2-Thiazolyl-, 2-Oxazolyl-, 2-Benzoxazolyl-, or 2-Benzothiazolyl-1-phenylethenols with α,β-Alkynyl Esters: Syntheses of Highly Functionalized Fused-Ring Heterocycles
作者:Hondamuni De Silva、Charles Pittman、William Henry
DOI:10.1055/s-0032-1316790
日期:——
with benzoyl chloride in acetonitrile containing triethylamine to give the corresponding (Z)-2-(heterocyclic)-1-phenylvinyl benzoates. Base hydrolysis of these vinyl benzoates gave the corresponding 2-(heterocyclic)-1-phenylethenols, which exist in both keto and enol tautomeric forms. These tautomers were used as starting materials for the syntheses of fused-ring heterocycles. The reactivity of the keto–enol
摘要 2-甲基-1,3-噻唑,2,4-二甲基-1,3-噻唑,2,4,5-三甲基-1,3-噻唑,2,4,5-三甲基-1,3-恶唑, 2-甲基-1,3-苯并恶唑和2-甲基-1,3-苯并噻唑分别用苯甲酰氯在乙腈中含有三乙胺,得到相应的(ž)-2-(杂环)-1-苯基乙烯基苯甲酸酯。这些乙烯基苯甲酸酯的碱水解得到相应的2-(杂环)-1-苯基乙烯醇,它们以酮和烯醇互变异构形式存在。这些互变异构体用作合成稠环杂环的原料。酮-烯醇互变异构体的反应性取决于杂原子和环上存在的取代基的性质。每个互变异构对与甲醇中的乙炔基二羧酸二甲酯(DMAD)反应生成5,6-环稠合的8-苯甲酰基-5-氧代-5 H-噻唑基-和8-苯甲酰基-5-氧代-5 H-恶唑并吡啶甲酸4 -苯甲酰基-1-氧代-1 H-吡啶[2,1- b ]苯并恶唑羧酸酯和4-苯甲酰基-1-氧代-1 H-吡啶[[2,1- b]]苯并噻唑羧酸酯衍生物。两种新颖的5