据报道,从1-或d-丝氨酸和乙醛酸乙酯开始直接合成(S)-和(R)-N -Boc-5-氧代-哌嗪-2-羧酸。通过1 H NMR光谱研究它们的二级结构,将它们评估为两个四肽的组成。在Boc-Val-(S)-PCA-Gly-Leu-OMe的情况下,观察到两个易于相互转化的构象(比例为40%:60%),不同之处在于叔酰胺键的顺式-反式异构化,而Boc-Val-(R)-PCA-Gly-Leu-OMe在γ-转角和II型β-转角构象之间显示出平衡。
据报道,从1-或d-丝氨酸和乙醛酸乙酯开始直接合成(S)-和(R)-N -Boc-5-氧代-哌嗪-2-羧酸。通过1 H NMR光谱研究它们的二级结构,将它们评估为两个四肽的组成。在Boc-Val-(S)-PCA-Gly-Leu-OMe的情况下,观察到两个易于相互转化的构象(比例为40%:60%),不同之处在于叔酰胺键的顺式-反式异构化,而Boc-Val-(R)-PCA-Gly-Leu-OMe在γ-转角和II型β-转角构象之间显示出平衡。
A straightforward synthesis of (S)- and (R)-N-Boc-5-oxo-piperazine-2-carboxylic acid is reported starting from l- or d-serine and ethyl glyoxylate. Those were evaluated as constituents in two tetrapeptides by studying their secondary structure by 1H NMR spectroscopy. In the case of Boc-Val-(S)-PCA-Gly-Leu-OMe, two readily interconverting conformations (in a 40%:60% ratio) were observed, differing for
据报道,从1-或d-丝氨酸和乙醛酸乙酯开始直接合成(S)-和(R)-N -Boc-5-氧代-哌嗪-2-羧酸。通过1 H NMR光谱研究它们的二级结构,将它们评估为两个四肽的组成。在Boc-Val-(S)-PCA-Gly-Leu-OMe的情况下,观察到两个易于相互转化的构象(比例为40%:60%),不同之处在于叔酰胺键的顺式-反式异构化,而Boc-Val-(R)-PCA-Gly-Leu-OMe在γ-转角和II型β-转角构象之间显示出平衡。