Betamethasone Intermediates In The Synthesis And Study

At present China can get tigogenin, byproduct of hemp producing industry, 500 tons per year from the waste water of hemp making industry. If we can not make rational utilization of tigogenin, heavily polluting the environment must be happen. In my thesis, in order to make rational utilization of the abundant steroidal sapogenins, we accomplished the study of the synthesis of of betameehasone intermediate (ⅠandⅡ) starting from pregnanetriol. Based on the previous research of my team, my work contains the following sections:1. Based on the regioselective acetylation-bromination, unimolecular elimination, selective oxidation, 3S-hydroxy-pregn-16-ene-20-one was obtained from pregnanetriol. Then through 1, 4-addition reaction, TMSCl substitution reaction, two times of epoxidation, ring cleavage, we completed the synthesis of betamethasone intermediateⅡin 8 steps with 7.91% overall yield.2. Based on the regioselective acetylation-bromination, unimolecular elimination, epoxidation from pregnanetriol, 16, 17- epoxy-pregn-3S, 20S- diol diacetate was obtained. Then through ring cleavage by Grignard reagent, we got the key intermediate, 16β-methyl-pregn-3, 17, 20-triol in 4 steps with 54% overall yield. And to get my target molecule from it, we still in the process of the synthesis of betamethasone intermediateⅠ.