Novel synthesis of 1,2,4-triazolophanes and 1,3,4-oxadiazolophanes: A dieckmann condensation approach
作者:Madhukar S. Chande、C. Sajithkumar、Hemant S. Mondkar、Pravin A. Barve、Sachin Diwan
DOI:10.1002/jhet.729
日期:2012.3
for the syntheses of novel 1,2,4‐triazolophanes and 1,3,4‐oxadiazolophanes. The bis‐1,3,4‐oxadiazol‐2‐thiols 1a and 1b were reacted with ethyl bromoacetate to give the diesters 2a and 2b. Diesters 2a and 2b were treated under dry conditions with sodium methoxide in methanol to afford desired symmetrical 1,3,4‐oxadiazolophanes 3a and 3b. Similarly, diesters of macrocycle precursors containing 1,2,4‐triazole
Dieckmann缩合首次被用于合成新型1,2,4-三唑烷和1,3,4-恶二唑烷。使bis-1,3,4-恶二唑-2-硫醇1a和1b与溴乙酸乙酯反应生成二酯2a和2b。将二酯2a和2b在干燥条件下用甲醇钠的甲醇溶液处理,得到所需的对称1,3,4-恶二唑烷3a和3b。类似地,含1,2,4-三唑部分大环化合物前体的二酯,即,图6a,图6b,10,13A,13B和13C是从合成图5a,图5b,9,图12A,12B,和12C分别。这些二酯,得到对称的酮的狄克曼缩合反应图7a,图7b,11,14A,14B,和14C。在常规的Dieckmann产物被稀无机酸中和期间原位水解后,观察到CO 2的挤出,从而以高收率提供高度对称的酮。此外,酮14a,14b和通过与Lawesson试剂的反应将14c转化成它们各自的硫酮。所有产物均以良好的产率合成,并且通过各种光谱学工具和元素分析证实了结构。J.杂环化学。,(2012)。