Water Solvent Method for Esterification and Amide Formation between Acid Chlorides and Alcohols Promoted by Combined Catalytic Amines: Synergy betweenN-Methylimidazole andN,N,N′,N′-Tetramethylethylenediamine (TMEDA)
作者:Hidefumi Nakatsuji、Jun-ichi Morita、Tomonori Misaki、Yoo Tanabe
DOI:10.1002/adsc.200600256
日期:2006.10
An efficient method for esterification between acid chlorides and alcohols in water as solvent has been developed by combining the catalytic amines, N-methylimidazole and N,N,N′,N′-tetramethylethylenediamine (TMEDA). The present Schotten–Baumann-type reaction was performed by maintaining the pH at around 11.5 using a pH controller to prevent the decomposition of acid chlorides and/or esters and to
通过将催化胺,N-甲基咪唑和N,N,N',N'-四甲基乙二胺(TMEDA)结合在一起,已开发出一种有效的方法,用于在水中作为溶剂在酰氯和醇之间进行酯化。通过使用pH调节剂将pH值保持在11.5左右,可以防止酸氯和/或酯类的分解并促进缩合,从而完成当前的Schotten-Baumann型反应。催化剂的选择(0.1当量)至关重要:N-甲基咪唑和TMEDA的组合使用具有显着的协同作用。催化胺具有两个不同的作用:(i)N-甲基咪唑与酰氯形成高反应性的铵中间体,并且(ii)TMEDA充当有效的HCl粘合剂。仔细的1 H NMR监测研究合理地支持了这些中间体的生产。在酰氯和伯胺或仲胺之间也实现了相关的酰胺形成,伯胺或仲胺包括较少的亲核或水溶性胺,例如2-(或4-)氯苯胺,Weinreb N-甲氧基胺和2,2-二甲氧基乙胺。