作者:Toshikatsu Maki、Kazuaki Ishihara、Hisashi Yamamoto
DOI:10.1016/j.tet.2007.03.157
日期:2007.8
meta- or para-position are highly effective catalysts for the amide condensation reaction in less-polar solvents. In this paper, we report that N-alkyl-4-boronopyridinium halides are more effective catalysts than the previous ones in more polar solvents. N-Alkyl-4-boronopyridinium halides are effective not only for amide condensation between equimolar mixtures of carboxylic acids and amines but also
1996年,我们报道了在间位或对位带有吸电子基团的苯硼酸是在极性较小的溶剂中进行酰胺缩合反应的高效催化剂。在本文中,我们报告了在极性更大的溶剂中,N-烷基-4-硼吡啶鎓卤化物比以前的催化剂更有效。ñ-烷基-4-硼烷基吡啶鎓卤化物不仅对于羧酸和胺的等摩尔混合物之间的酰胺缩合有效,而且对于在醇溶剂中α-羟基羧酸的酯化都是有效的。此外,对于空间上需要的羧酸的酰胺缩合,全氯儿茶酚硼烷比芳烃硼酸更有效。此外,路易斯酸辅助的布朗斯台德酸(LBA)由硼酸和四氯邻苯二酚的1:2 M混合物制得,对从醇和腈到酰胺的Ritter反应有效。