Molecular rotations of Nα-acyl-L-lysines were determined in water and in water containing various amounts of HCl or NaOH. The acyl groups were formyl, acetyl, propionyl, and butyryl. Each Nα-acyl-L-lysine exhibited more negative rotation in HCl or NaOH solution than in water. The plot of molecular rotation against amount of HCl or NaOH resembled that of a D-α-amino acid even though Nα-acyl-lysine was of L-form. The reason for this is discussed from the standpoint of steric factors. Nε-Acyl-L-lysines corresponding to the Nα-acyl-L-lysines were synthesized as reference compounds. It was found that water-soluble Nε-acyl-L-lysines can be easily prepared by acylation of the Cu complex solution of L-lysine hydrochloride in the presence of triethylamine. The molecular rotation plots for Nε-acyl-L-lysines were typical of L-α-amino acids.
测定了 Nα-acyl-L-lysine 在
水中和含有不同量 HCl 或 NaOH 的
水中的分子旋转。酰基包括甲酰基、乙酰基、丙酰基和丁酰基。每种 Nα-acyl-L-lysine 在
盐酸或 NaOH 溶液中都比在
水中表现出更多的负旋转。分子旋转与 HCl 或 NaOH 溶液量的关系图类似于 D-
α-氨基酸,尽管 Nα-acyl-lysine 是 L-形式。我们将从立体因素的角度讨论出现这种情况的原因。合成了与 Nα-酰基-
L-赖氨酸相对应的 Nε-酰基-
L-赖氨酸作为参考化合物。研究发现,在
三乙胺存在下,通过对
L-赖氨酸盐酸盐的
铜络合物溶液进行酰化,可以很容易地制备出
水溶性 Nε-酰基-
L-赖氨酸。Nε-acyl-L-lysines 的分子旋转图是典型的 L-
α-氨基酸。