作者:Fumiki Nomoto、Yoshihiko Hirayama、Masaya Ikunaka、Toru Inoue、Koutaro Otsuka
DOI:10.1016/s0957-4166(03)00363-x
日期:2003.7
(+/-)-3-Butyryloxyquinuclidinium butyrate 6 (2 M, 571 g/L), prepared from (+/-)-quinuclidin-3-ol 1 and butyric anhydride, undergoes enantioselective hydrolysis by an Aspergillus melleus protease 1.0% (w/v)} in water in the presence of Ca(OH)(2) to keep the reaction at pH 7 and trap butyric acid that is introduced as part of (+/-)-6 and generated by the enzymatic hydrolysis. After a 24 h period, extraction with n-heptane provides (R)-quinuclidin-3-yl butyrate 5a, which, on methanolysis with Na2CO3, is converted into (R)-1, a common pharmacophore of neuromodulators acting on muscarinic receptors, in 96% ee and 42% overall yield from (+/-)-1. The unwanted antipode (S)-1, which is extracted into n-butanol and purified via its hydrochloride salt in 89% ee and 40% overall yield from (+/-)-1, can be racemized by the catalysis of Raney Co at 140degreesC under an atmosphere of H, (5 kg/cm(2)) to regenerate (+/-)-1 in 97% yield. (C) 2003 Elsevier Science Ltd. All rights reserved.
(+/-)-3-丁酰氧基奎宁环季铵盐丁酸盐6(2M,571g/L)由(+/-)-奎宁环-3-醇1和丁酸酐制得,经 fullNameAspergillus melleus fullName酶(1.0% w/v)在水溶液中进行不对称水解,同时加入Ca(OH)₂以维持反应pH7并固定由(+/-)-6引入且被酶解产生的丁酸。反应24小时后,用正庚烷萃取出(R)-奎宁环-3-基丁酸酯5a,其在甲醇中经Na₂CO₃甲氧基化后转化为(R)-1,这是作用于毒覃碱受体的神经调节剂的共同药效团,其对映体纯度为96%,总产率为从(+/-)-1的42%。不受欢迎的对映体(S)-1可通过正丁醇萃取并经其盐酸盐纯化,对映体纯度为89%,总产率为从(+/-)-1的40%。该对映体可通过Raney Co催化在含H气氛(5kg/cm²,140°C)下消旋化,以97%的产率再生(+/-)-1。(C)2003 Elsevier Science Ltd.版权归作者所有。