An Anomeric Effect Drives the Regiospecific Ring-Opening of 1,3-Oxazolidines under Acetylating Conditions
作者:R. Fernando Martínez、Martín Ávalos、Reyes Babiano、Pedro Cintas、José L. Jiménez、Mark E. Light、Juan C. Palacios、Esther M. S. Pérez
DOI:10.1002/ejoc.201000636
日期:2010.9
the oxazolidine moiety under acetylating conditions to afford imines instead of N-acetyloxazolidines. This process was monitored by 1H NMR spectroscopy, corroborated by synthesis, and rationalized by the intermediacy of an iminium ion. Oxazolidine–imine equilibria are also described for TRIS and other aminopolyols. The equilibria are shifted to the heterocyclic partner as the number of reactive hydroxy
一系列衍生自三(羟甲基)氨基甲烷 (TRIS; 1) 的恶唑烷已被有效地制备。在 B3LYP/6-31G* 理论水平上优化的几何结构,连同化合物 9 和 12 的晶体数据以及 NOESY 相关性,都指向了一种强大的内异头效应,它锚定了一个优先构象,随后决定了完全区域选择性的开环恶唑烷部分在乙酰化条件下得到亚胺而不是 N-乙酰恶唑烷。该过程由 1 H NMR 光谱监测,通过合成证实,并通过亚胺离子的中间体进行合理化。还描述了 TRIS 和其他氨基多元醇的恶唑烷-亚胺平衡。随着活性羟基数量的增加,平衡向杂环伙伴转移。
Reactivite du tris(hydroxymethyl)aminomethane avec des nitro-aldehydes aromatiques. Synthese de nouveaux composes antimicrobiens.