Synthesis of N-acyl-N,α,α-trialkyl and N-acyl-α,α-dialkyl glycines by selective cleavage of Ugi–Passerini adducts. Qualitative assessment of the effect of substituents on the path and yield of reaction
作者:Wei-Qun Jiang、Susana P. G. Costa、Hernâni L. S. Maia
DOI:10.1039/b307111c
日期:——
symmetric N-acyl-N,alpha,alpha-trialkyl glycine amides were synthesised by the Ugi-Passerini four-component reaction and subjected to selective cleavage with trifluoroacetic acid. In almost all cases it was possible to obtain the corresponding N-acyl-N,alpha,alpha-trialkyl and N-acyl-alpha,alpha-dialkyl glycines in fair to good yields directly from the reaction adducts. With some of the bulkier compounds
通过Ugi-Passerini四组分反应合成了几种对称的N-酰基-N,α,α-三烷基甘氨酸酰胺,并用三氟乙酸进行了选择性裂解。在几乎所有情况下,都可以直接从反应加合物中以相当高的收率获得相应的N-酰基-N,α,α-三烷基和N-酰基-α,α-二烷基甘氨酸。对于某些体积较大的化合物,我们的结果表明,裂解的选择性相对于酸而言是浓度依赖性的,这提示了动力学控制的过程。作为某些反应产物的稳定的恶唑酮的分离似乎证实了酰胺裂解在所有情况下都涉及恶唑酮型衍生物的形成。