Lipase-catalyzed synthesis of chiral poly(ester amide)s with an alternating sequence of hydroxy acid and L/D-aspartate units
Lipase-catalyzed synthesis of chiral poly(ester amide)s with an alternating sequence of hydroxy acid and L/D-aspartate units
复制标题
脂肪酶催化合成具有羟基酸和 L/D-天冬氨酸单元交替序列的手性聚（酯酰胺）
DOI：
10.1039/c7py01936j
复制
发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Qi Wu
中科院分区：
文献类型：
--
作者：
Yiru Liang;Yu Zhang;Yujing Hu;Bo Xia;Xianfu Lin;Qi Wu
目前报道的聚酯酰胺的合成方法大多存在氨基酸和酯基序列难以控制以及环境污染等问题。本文中，我们开发了一种简便的方法用于脂肪酶催化合成具有交替天冬氨酸和羟基己酸（HA）单元的手性L-/D-Asp基聚（酯酰胺）。在Novozym 435催化的缩聚反应中，以L-或D-天冬氨酸构型的N-（6-羟基己酰基）天冬氨酸二酯和天冬氨酸的α或β-羰基位上的甲基或苄基酯为原料，成功地合成了相应的α-苄基或α-甲基酯交替的聚（HA-alt-L/D-β-天冬氨酸）。在Novozym 435催化的缩聚反应中，L-天冬氨酸双酯单体比D-天冬氨酸双酯单体更优先生成，且具有较高的区域选择性，主要形成天冬氨酸单元的β-键。在四种聚酯酰胺中，聚（HA-alt-L-α-苄基-β-天冬氨酸酯）的摩尔质量最高，达13 000 Da，β-键含量高达98%。 这些交替的聚（HA-alt-L/D-天冬氨酸）的热性能和聚集体的微观结构进行了比较，并观察到一些有趣的差异。我们的研究结果还表明，这些对映体纯的聚（HA-alt-L/D-天冬氨酸）没有形成立体复合物。
Most of reported synthesis approaches for poly(ester amide)s suffer from the difficulty in controlling the sequence of amino acid and ester units, and also some environmental disadvantages. Herein, we developed a facile approach for the lipase-catalyzed synthesis of chiral L-/D-Asp-based poly(ester amide)s with alternating aspartate and hydroxyhexanoic acid (HA) units. In the Novozym 435-catalyzed polycondensation starting from four monomers, namely N-(6-hydroxyhexanoyl) aspartate diesters with an L- or D-aspartate configuration, and methyl or benzyl ester groups at the α or β-carbonyl positions of Asp, we successfully obtained the corresponding alternating poly(HA-alt-L/D-β-aspartate)s with α-benzyl or α-methyl ester groups. The L-aspartate diester monomer was preferred to the D-aspartate diester monomer in the Novozym 435-catalyzed polycondensation, and it also showed high regioselectivity, mainly forming the β-linkage of the aspartate unit. Among the four poly(ester amide)s, poly(HA-alt-L-α-benzyl-β-aspartate) has the highest molar mass of up to 13 000 Da and 98% β-linkage. The thermal properties and the aggregate microstructures of these alternating poly(HA-alt-L/D-aspartate)s were also compared and some interesting differences were observed. Our results also showed that these enantiopure poly(HA-alt-L/D-aspartate)s did not form a stereocomplex.