Studies on the diastereoisomeric and conformational aspects of benzoyl dipeptide esters, as a means of assessing racemisation using nuclear magnetic resonance spectroscopy
作者:John S. Davies、R. John Thomas
DOI:10.1039/p19810001639
日期:——
Distinct methyl ester signals in the 1Hn.m.r. spectra of diastereoisomeric forms of benzoyl dipeptide methyl esters provide a means of estimating the isomer composition of diastereoisomeric mixtures. Analysis of the mixture derived from peptide-coupling reactions using this n.m.r. technique provides a convenient means of comparing the racemisation potential of a series of coupling reagents. Significant
苯甲酰基二肽甲基酯的非对映异构体形式的1 H nmr光谱中的不同甲酯信号为估算非对映异构体混合物的异构体组成提供了一种手段。使用这种核磁共振技术对衍生自肽偶联反应的混合物进行分析,为比较一系列偶联试剂的消旋潜力提供了便利的方法。在模型肽偶联过程中,显着的不对称诱导伴随着外消旋作用。已使用13 C nmr光谱研究了构象效应,并已合理化了在1 H nmr光谱中观察非对映异构酯信号的结构标准。
Asymmetric Induction during the Aminolysis of 5(4<i>H</i>)-Oxazolones from<i>N</i>-Benzoyl Amino Acids; Almost Specific Formation of One Epimer in the Reaction of the Oxazolone from<i>N</i>-Benzoyl-DL-<i>t</i>-leucine with Methyl L-Prolinate
Asymmetric induction during the aminolysis of 5(4H)-oxazolonesfrom N-benzoyl amino acids was investigated using a series of amino acid esters as amine nucleophiles. The reaction of the oxazolone from N-benzoyl-DL-t-Meucine with methyl L-prolinate was found to produce the diastereomeric DL isomer, almost specifically, under appropriate conditions.