离子液体协同催化合成游离氨基酸酯

以L-氨基酸和醇为原料,酸性离子液体辅以少量强酸性阳离子交换树脂作催化剂,直接酯化合成了8种游离的L-氨基酸酯,并用1HNMR对产物进行了表征。通过L-苯丙氨酸正丁酯的合成对离子液体的活性进行了考察,结果表明,所选用的11种离子液体在反应过程中均起到了一定的催化作用和助溶作用。其中,Hmim]HSO4]效果较好,在重复使用后,显示了较好的稳定性,是氨基酸酯化反应理想的催化剂和助溶剂。

Synthesis of free amino acid esters co-catalyzed by ionic liquid

Eight kinds of free L-amino acid esters including L-phenylalanine ethyl ester, L-phenylalanine n-butyl ester, L-phenylalanine i-butyl ester, L-tyrosine n-butyl ester, L-tyrosine i-butyl ester, L-tyrosine i-amyl ester, L-aspartic n-butyl diester and L-aspartic i-butyl diester were synthesized by direct esterification of L-amino acid and alcohol with acidic ionic liquid assisted by strong acidic cation resin as catalyst. The structures of free L-amino acid esters were characterized by 1HNMR. Optimal reaction conditions were obtained when synthesizing L-phenylalanine n-butyl ester. Among eleven kinds of the acidic ionic liquids used in this case, Hmim]HSO4 indicated excellent activity and the catalyst is easily regenerated and reused. By this token, it exhibits its potential application as catalyst and co-solvent in the esterification of amino acid.