Chemoselective <i>N</i>-Acylation via Condensations of <i>N</i>-(Benzoyloxy)amines and α-Ketophosphonic Acids under Aqueous Conditions
作者:Jasbir Singh Arora、Navneet Kaur、Otto Phanstiel IV
DOI:10.1021/jo800223j
日期:2008.8.1
22% yield upon addition of 2 equiv of TFA. The N-acylation reaction is highly chemoselective for N-benzoyloxyamines as both aliphatic amines and N-hydroxylamines were shown not to react productively with the α-ketophosphonic acids under the conditions tested. Moreover, the α-ketophosphonic acids are more selective than the related α-ketocarboxylic acid systems, which react with both the N-hydroxylamines
研究了一种新的与N-苯甲酰氧基胺和α-酮膦酸形成酰胺的反应。在40°C时,叔丁基醇/水(1:1)的混合溶剂以高收率(71-96%)提供了所需的酰胺。两个膦酸(9,12,或13)和它们的二钠盐(例如,10)显示出与相应的反应Ñ -benzoyloxyamines(1B和4以优良产率)。膦酸甲酯单钠盐11在这些条件下不反应。然而,添加2当量的TFA后,化合物11确实以22%的收率提供了所需的酰胺。这N-酰化反应对N-苯甲酰氧基胺具有高度化学选择性,因为在所测试的条件下,脂族胺和N-羟胺均未与α-酮膦酸产生有效反应。而且,α-酮膦酸比与相关的α-酮羧酸体系选择性更高,后者与N-羟胺和N-苯甲酰氧基胺反应。在这方面,这种新颖的膦酸方法学提供了一种新的高产,化学选择性的酰化试剂,以供进一步研究。