603121-51-3Relevant articles and documents
A practical chemoenzymatic process to access (R)-quinuclidin-3-ol on scale
Nomoto, Fumiki,Hirayama, Yoshihiko,Ikunaka, Masaya,Inoue, Toru,Otsuka, Koutaro
, p. 1871 - 1877 (2003)
(±)-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 140°C under an atmosphere of H2 (5 kg/cm2) to regenerate (±)-1 in 97% yield.
