Reaction of N-benzyloxycarbonyl derivatives of aliphatic amino acids, and threonine, aspartic, and glutamic acids whose side-chains were protected with the t-butyl group, gave the corresponding N-methylamino acid derivatives in good yields. The methionine derivative could be obtained by using only one mol of methyl iodide. Derivatives of threonine, and aspartic and glutamic acids whose side-chains were not protected could not be methylated. Analysis of the crude products of methylation in three cases showed that they contained 0–1% of racemized material.
N-苄氧羰基衍生物与保护有叔丁基侧链的脂肪族氨基酸、苏氨酸、天冬氨酸的反应,产生相应的N-甲基氨基酸衍生物,收率较高。甲硫氨酸衍生物可以仅使用一摩尔的碘甲烷获得。苏氨酸、天冬氨酸的衍生物,其侧链未受保护的情况下无法进行甲基化。对三种情况下甲基化的粗产品进行分析显示,含有0-1%的消旋杂质。