Indoles via Knoevenagel–Hemetsberger reaction sequence
作者:William L. Heaner IV、Carol S. Gelbaum、Leslie Gelbaum、Pamela Pollet、Kent W. Richman、William DuBay、Jeffrey D. Butler、Gregory Wells、Charles L. Liotta
DOI:10.1039/c3ra42296h
日期:——
sequential reaction of aromatic aldehydes with ethyl azidoacetate in the presence of sodium ethoxide to form the corresponding ethyl α-azido-β-arylacrylates (Knoevenagel process) followed by a solvent mediated thermolysis (Hemetsberger process). The isolated yields of the ethyl α-azido-β-arylacrylates were significantly increased when employing the sacrificial electrophile ethyl trifluoroacetate. 1H NMR and
通过芳族醛与环戊烯的顺序反应合成了一系列取代的吲哚叠氮基乙酸乙酯 在......的存在下 乙醇钠形成相应的乙基α-叠氮基-β-芳基丙烯酸乙酯(Knoevenagel法),然后进行溶剂介导的热分解(Hemetsberger法)。使用牺牲亲电试剂时,α-叠氮基-β-芳基丙烯酸乙酯的分离收率显着提高三氟乙酸乙酯。对α-叠氮基-β-芳基丙烯酸乙酯的1 H NMR和1 H- 13 C NMR耦合分析表明,该缩合反应具有立体特异性,只能检测到Z异构体。溶剂介导的间位取代的乙基α-叠氮基-β-芳基丙烯酸酯的热处理导致5位和7位取代的吲哚的形成,其中5位区域异构体比7位区域异构体略受青睐。(2 Z,2 Z ')-二乙基3,3'-(1,3-亚苯基)双(2-叠氮基丙烯酸酯)和(2 Z,2 Z ')-二乙基3,3'-(1的相似热处理,4-亚苯基)双(2-叠氮基丙烯酸酯)专门生产吡咯并吲哚,1,5-二氢吡咯并[2
KATTI, H. A.;SIDDAPPA, S., INDIAN J. CHEM., 1983, 22, N 12, 1205-1208