Study Of Synthesis Of C-nor-D-homo Steroid Skeleton

The progress of preparing C-nor-D-homo steroid skeleton was studied in this paper. The starting material hecogenin was acetylated to hecogenin acetate. Hecogenin acetate was reducted by NaBH4 to give 12-hydroxy hecogenin acetate. Then 12-hydroxy hecogenin acetate was esterified with PTSC to give Compound 4. At last Compound 4 was rearranged in refluxing pyridine to give objective product C-nor-D-homo skeleton.The influencing factors of acetylation were analyzed by orthogonal test, and the optimum condition of acetylation was the following: reaction temperature 100℃, the amount of acetic anhydride 2eq.,the amount of DMAP 0.01eq.,reaction time 1 hour。Under appropriate condition,the yield of hecogenin acetate was 90.03%。The influencing factors of acetylation were analyzed by orthogonal test, and the optimum condition of acetylation was the following: reaction temperature 0℃,the amount of NaBH4 0.3eq.,the amount of CeCl3·7H2O 0.1eq.,reaction time 15 minutes. Under appropriate condition,the yield of 12-OH hecogenin acetate was 93.25%。The influencing factors of acetylation were analyzed by orthogonal test, and the optimum condition of acetylation was the following: reaction temperature 20℃,the amount of PTSC 1.25eq.,reaction time 72 hours。Under appropriate condition,the yield of Compound 4 was 89.74%。The influencing factors of rearrangement reaction solvent condition was studied. The appropriate solvent condition is pyrdine, give the highest yield 85.18%。The acetylation reaction under microwave irradiation was also studied, carrying out the fast synthesis of Compound 2 of sovlent-free condition. And the optimum condition was the following:the power of microwave irradiation 520W,no catalyst,reaction time 6min,and yield 91.41%。The synthesis of Compound 5 through one-pot method under microwave irradiation was studied, decurtating the reaction time significantly. And the optimum condition was the following:the power of microwave irradiation 650W, reaction time 40min, the amount of PTSC 1.1eq., yield 49.91%。...