| 摘要 |
The process allows a virtually quantitative conversion of the configuration of prostaglandines F alpha into F beta . To this end, the 9 alpha -hydroxyl group is esterified selectively with a carboxylic acid in the presence of a hydrogen acceptor, for example quinones or azodicarboxylic esters, and of a catalyst M<V>Y3 in which M<V> denotes a non-metal of group V and Y denotes an alkyl, dialkylamino or aryl group, for example triphenylphosphine, triphenylarsine or triphenylstibine, and the resulting 9 beta -acyloxy radical and other acyloxy radicals which may be present are hydrolytically cleaved. To ensure specific esterification, ether groups which are present can be cleaved before or after hydrolysis while setting free the hydroxyl groups. The hydrolysis process can be carried out in such a manner that not only the acyloxy radicals but also a terminal carboxylate group are cleaved simultaneously or in succession. |
