就地硼氢化法的改进——雌三醇合成工艺的研究

IMPROVED SYNTHESIS OF ESTRIOL VIA HYDROBORATION IN SITU

在前报中,我们应用外源性硼烷进行硼氢化反应,成功地改进了合成雌三醇(3)的工艺,收率高达85～95％;并以闪式柱层析分离出两个副产物:表雌三醇(4)和雌三醇-17-乙基醚(5):

The Estriol (3) was successfully syntheszed in 85—90% yield from estra-1,3,5(10),16-tetraen-3,17-diacetate (2) by hydroboration procedure, in which diborane was generated externally. As earlier reports stressed the hazard of diborane, it was difficult to put this procedure into industrial practice. In the known conventional procedure of hydroboration with Diborane generated in situ, the yield of (3) was terribly low (only 18.4%). The procedure in situ was improved as follows: First, BF_3·EtOEt was added into the suspension of sodium borohydride in THF, then its supernatant was used to react with diacetate (2), the yield of (3) could be up to 82-86% by this way.