X=Y-ZH compounds as potential 1,3-Dipoles. Part 231,2 mechanisms of the reactions of ninhydrin and phenalene trion with ∝-amino acids. X-ray crystal structure of protonated ruhemann's purple, a stable azomethine ylide
作者:Ronald Grigg、John F. Malone、Theeravat Mongkolaussavaratana、Sunit Thianpatanagul
DOI:10.1016/s0040-4020(01)89244-9
日期:1989.1
3-trione reacts with ∝-amino acids via a different mechanism despite the formal similarity of the two reagents. In this case decarboxylation occurs in a carbinolamine and azomethine ylides are not involved. An X-ray crystal structure of protonated Ruhemann's Purple shows it to be a stable N-H azomethine ylide, confirming the results of cycloaddition studies.
茚三酮反应显示出通过用马来酰亚胺作为双极性亲和剂捕获中间体而涉及两种立体定向形成的甲亚胺基团。其中保留了原始α-氨基酸的羧基的一种甲亚胺叶立德可能仅对甘氨酸很重要。另一种类型的甲亚胺叶立德不含羧基,是由所有茚三酮正α-氨基酸通过恶唑烷-5-酮前体的脱羧环还原反应形成的。尽管两种试剂在形式上相似,但苯酚-1,2,3-三酮通过不同的机理与α-氨基酸反应。在这种情况下,脱羧发生在甲醇胺中,并且不涉及偶氮甲碱。质子化的Ruhemann紫的X射线晶体结构表明它是稳定的NH甲亚胺叶立德,