An Improved Chemo-Enzymatic Synthesis of 1-β-<i>O</i>-Acyl Glucuronides: Highly Chemoselective Enzymatic Removal of Protecting Groups from Corresponding Methyl Acetyl Derivatives
作者:Akiko Baba、Tadao Yoshioka
DOI:10.1021/jo701547b
日期:2007.12.1
developed from the corresponding methyl acetyl derivatives 3a−f, which were stereospecifically synthesized from cesium salts of carboxylic acids 1a−f and methyl 2,3,4-tri-O-acetyl-1-bromo-1-deoxy-α-d-glucopyranuronate (2). Chemoselectivity of lipase AS Amano (LAS) in the hydrolytic removal of O-acetyl groups of 3a−f to provide methyl esters 4a−f was influenced by the nature of their 1-β-O-acyl groups; high
的一系列的合成一种改进的和广泛适用的化学-酶促方法1-β- ö酰基葡糖苷酸5A - ˚F已从乙酰基衍生物相应的甲基开发3A - ˚F,将其立体专一从羧酸铯盐合成1a - f和2,3,4-三-O-乙酰基-1-溴-1-脱氧-α- d-吡喃葡萄糖醛酸甲酯(2)。在水解去除的脂肪酶AS天野(LAS)的化学选择性Ö的乙酰基团3A - ˚F提供甲酯4A -f受其1-β- O-酰基基团性质的影响;只有3b和3f才有很高的选择性。新近筛选出可替代LAS的罗氏链霉菌(CSR)的羧基酯酶显示出比LAS更高的对O-乙酰基的化学选择性。仅通过CSR化学选择性水解3a,3d和3e。CSR与LAS的组合比单独使用CSR产生的3c和3f水解效果更好。最终脱保护4a - f的甲基酯基团以提供图5a - ˚F是化学选择性通过使用脂肪酶从实现念珠菌南极类型B(CAL-B),以及来自猪肝脏(PLE)的酯酶,虽然CAL-B具有更