Progesterone -16 - En-3s, 20s-diol Diacetate Of Palladium-catalyzed Reaction And Betamethasone Intermediate Synthesis

Tigogenin is a byproduct in the hemp-making industry using the sisal, as a castoff, it pricks up environmental pollutant. How to rationally utilize resource compound Tigogenin and eliminate pollution of hemp-making industry is critical. Based on the research of rational utilization of the abundant steroidal sapogenins, the efficient and terse synthesis of pregn-16-ene-3S, 20S-diol diacetate starting from pregnanetriol was developed. As the continuation of previous research, my dissertation focused on the following sections:1. The Pd-catalyzed reaction of Pregn-16-ene-3S, 20S-diol diacetate with nucleophilic reagents was reinvestigated. Some useful and new results were obtained through such investigation. The research results showed that the C-20 nucleophilic product 5 is predominant in the presence of Pd(OAc)2 while the C-20 elimination product pregna-16, 20-diene-3S-acetate is dominated in the presence of [PPh3]4Pd.2. Based on the regioselective acetylation-bromination, hydrolysis, Swern oxidation and the following elimination, pregn-16-ene-3, 20-dione was obtained. Then through Michael reaction, epoxidation , ring cleavage and so on , we finished the synthesis of Betamethasone intermediate 15 in 8 steps in 7.5% overall yield starting from pregnanetriol.These results not only provided new idea for the syntheses of steroidal drugs and natural steroids, but also presented more opportunity for rational utilization Tigogenin.