钙伯三醇的关键中间体——麦角甾烷-5,7(E),10(19)-三烯-6(S)-二氧化硫的合成

Synthesis of A Key Imtermediate of MC903——Ergosta-5,7(E),10(19)-triene-6(S)-sulfur Dioxide

麦角甾烷-5,7(E),10(19),22(E)-四烯-6(S)-二氧化硫(1)经臭氧化反应合成了钙伯三醇(MC903)的重要中间体——麦角甾烷-5,7(E),10(19)-三烯-6(S)-二氧化硫(2),其结构经1H NMR和13C NMR表征。较佳的臭氧化反应条件为:11.0mmol,溶剂为V(二氯甲烷)∶V(甲醇)=4∶1,于-65℃^-78℃反应12min。在此条件下,2中醛基α-位的差相异构化降至最低程度,产率90%。对差相异构化的机理进行了讨论。

The Key Imtermediate of MC903 ergosta-5,7（E） ,10（19）-triene-6（S）-sulfur dioxide （2） was synthesized from ergosta-5,7 （E）, 10 （ 19 ） ,22（E） -tetraterpene-（6S） -sulfur dioxide （ 1 ） by ozonization. The structure was characterized by 1H NMR and ^13C NMR. The optimal ozonization conditions at -65 ℃ -78 ℃ for 12 min were as follows： 1 was 1.0 mmol; solvent V（CH2Cl2） ：V （MeOH） was 4 ： 1. The degree of epimerization in the a-position of aldehyde group was minimized under the optimal conditions and the yield was 90.0%. The mechanism of epimerization was also discussed.