有机碱在脂肪酶Candida antarctica B催化仲醇拆分中的促进作用

以离子液体bm im]PF6为反应溶剂,乙酸乙烯酯为酰基供体,考察了脂肪酶Candida antarcticaB催化外消旋仲醇的动力学拆分。主要考察了有机碱和无机碱对拆分反应的影响,结果发现,在反应底物中加入三乙胺或吡啶,能够极大地提高脂肪酶的活性和对映选择性,当底物邻甲氧基-α-苯乙醇和1-(2-萘基)乙醇在拆分时加入吡啶后,脂肪酶的对映选择性是未加入有机碱时的5~8倍,分别从E=65提高到E=525和从E=209提高到E=1 059,因此,可高对映选择性地获得邻甲氧基-α-苯乙醇和1-(2-萘基)乙醇的手性单体。随着吡啶加入量的增加,脂肪酶的对映选择性有所下降,因此,有机碱的最佳加入量为0.01 mol,原因可能是在该加入量下,脂肪酶达到了最佳pH,即处于活性构象,从而具有较高的活性和对映选择性。

Enhanced Effect of Organic Bases on the Lipase-Catalyzed Kinetic Resolution of Secondary Alcohols

The lipase-catalyzed kinetic resolution of secondary alcohols was studied using vinyl acetate as acyl donor in ionic liquid PF6.Effect of organic bases and inorganic base on the kinetic resolution reaction were studied.The presence of organic base such as triethylamine or pyridine considerably improved the catalytic activity and enantioselectivity of the lipase,and it was observed that in the kinetic resolution of 2-methoxy-a-methylbenzyl alcohol and 1-(2-naphthyl) ethanol,addition of pyridine increased the...