.16 S-20s-epoxy Progesterone-3s-ol Acetate Synthesis And The Regioselectivity Of Epoxide Open-loop Substitution Reaction

Along with the development of human society, the problems of the growing lack of resources, increasing environmental pollution and other issues have become increasingly prominent. How to improve resource utilization and reduce waste of resources became one of the important tasks of chemical workers. The rational utilization of resource compounds is one of the main tasks in our research lab. Based on the research of rational utilization of the abundant steroidal sapogenins, my dissertation is concerned on the following sections:(1) In this paper, a synthetic method of 16S,20S-epoxypregnane-3S-ol acetate(5) from pregnane-3S,16S,20S-triol was developed. Using pregnane-3S,16S,20S-triol (a tigogenin degradation product) as the starting material, through a sequence of reaction involved acetylation-bromination, hydrolysis, epoxidation and acetylation we completed the synthesis of 16S,20S-epoxypregnane-3S-ol acetate(5) in 4 steps in 72.8% overall yield.(2) The epoxide-opening reaction of 16S,20S-epoxypregnane-3S-ol acetate(5) was investigated under different conditions. The research results showed that 16S, 20S-epoxypregnane-3S-ol acetate was chemo-selectively converted into 20R-bromopregnane-3S,16S-diol diacetate,20R-bromopregnane-3S, 16S-diol-3-acetate,20R-chloropregnane-3S,16S-diol diacetate,20R-iodopregnane-3S, 16S-diol-3-acetate and pregnane-3S,16S,20R-triol-3-acetate. These results not only provided new synthetic intermediates for the syntheses of steroidal drugs and natural steroids, but also presented epoxide-opening methods of steroids having a asymmetric oxetane ring.