| 摘要 |
Pregnane derivs. of partial formula (I): (where R1 is CH3 or C2H5 and R2 is H, hydrocarbyl or acyl) are prepd. by reacting a sulphite ester of formula (II): with an alcohol or a carboxylic acid in the presence of a water-binding agent and an Hg(II) salt and opt. cleaving the resulting cpd. (I; R2 is not =H) to give (I; R2 = H). The new procedure enables 17 alpha-oxy-pregnane derivs. to be obtd. by an easily performed 3-stage synthesis from 17-oxo-androstanes and -oestranes and is therefore of use in the total synthesis of pregnane cpds. such as gestagenic 17 alpha-hydroxyprogesterones or antiphlogistic corticoids. |
