| 摘要 |
<p>A polyhydroxyl steroid of pregnane series, 9alpha-chloro 11beta,17alpha,21-trihydroxy 16beta-methyl 1,4-pregnadien-3,20-dione of formula (I) is reacted with a light molar excess of methanosulphonyl chloride in dioxane/pyridine medium at -10 to -2 deg.C for 1-2 h. to obtain the 21-methawsulphonate ester. This is isolated by pouring onto water and ice and crystallised from a strongly-polar solvent, e.g. acetone, ethyl acetate or ether, until the melting range is below 2 deg.C it is used as an intermediate for prepn. of the 21-(2-hydroxy benzoate) ester.</p> |
