Influence of Chirality of the Preceding Acyl Moiety on the <i>cis</i>/<i>trans</i> Ratio of the Proline Peptide Bond
作者:Matej Breznik、Simona Golič Grdadolnik、Gerald Giester、Ivan Leban、Danijel Kikelj
DOI:10.1021/jo0159439
日期:2001.10.1
in (1)H NMR spectra. The signals were assigned to trans (72%) and cis (28%) conformers. Crystallographic analysis of 4 showed that only the cis conformation is present in the crystalline state. The (1)H NMR chemical shift pattern of three sets of signals observed in 2 was observed also in benzyl (2S)-1-[(2R/S)-3-methoxy-2-methyl-2-(4-methyl-2-nitrophenoxy)-3-oxopropanoyl]-2-pyrrolidinecarboxylate. (R)-Carboxylic
我们报道脯氨酸肽键的顺式/反式比可以强烈地受到脯氨酸之前的酰基残基的手性的影响。衍生自(2S)-2,6-二甲基-3-氧代-3,4-二氢-2H-1,4-苯并恶嗪-2-羧酸(8)和(2R)-3-甲氧基-2-的酰基部分酰基-Pro分子中的甲基-2-(4-甲基-2-硝基苯氧基)-3-氧代丙酸(5)影响脯氨酸肽键的异构化,从而将欧米茄二面角限制为反式。(2S)-1-([[(2S)-2,6-二甲基-3-氧代-3,4-二氢-2H-1,4-苯并恶嗪-2-基]羰基)-2-吡咯烷羧酸酯( 3)源自2D(1)H NMR构象分析和晶体学数据,仅显示脯氨酸肽键的反式构象。另一方面,含有(R)酰基部分的非对映异构体4在(1)1 H NMR光谱中显示出两组信号。将信号分配给反式(72%)和顺式(28%)构象体。4的晶体学分析表明仅顺式构象以结晶状态存在。在苄基(2S)-1-[(2R / S)-3-甲氧基-2-甲基-2-