L-脯氨醇的合成

Synthesis of L-Prolinol

用NaBH4 /I2 还原体系将L 脯氨酸(L proline)直接还原得到L 脯氨醇。通过对其还原和水解工艺的优化,获得规模制备的最优条件是:n(NaBH4 )∶n(I2 )∶n(L proline) =2 5∶1 75∶1,室温下滴加碘,回流反应20h,然后在w(NaOH) =20%的水溶液中90℃水解3h。产品L 脯氨醇的收率为88 4%,光学纯度大于99%。

L-Prolinol was obtained from L-proline by direct reduction with NaBH_4 /I_2 system.The optimal reaction conditions in large-scale preparation are as follows.Reduction was performed by refluxing 20 h with n(NaBH_4):n(I_2):n(L-proline)=2.5∶1.75∶1 after dropping addition of I_2 solution at room temperature.Hydrolysis was carried out with w(NaOH)=20 % solution at 90 ℃ for 3 h.Yield of L-prolinol reached 88.4% and the enantiomerical purity of L-prolinol was up to 99%.