| 摘要 |
In a process for preparing a compound of formula (I), in which R1 is H, an alkyl, alkoxy, or hydroxyalkyl radical or halogen, and R3 is N3 or a CN radical, a compound of formula (II), is reacted with a phosphine derivative, an azo-dicarbonylic acid diester and a carboxylic acid R2-COOH in a solvent compatible with the reaction conditions to yield the compound of formula (III), which, after possible separation, is opened in the presence of a azotide or a cyanide in a solvent compatible with the reaction conditions. The compound of formula (I), is then isolated from the reaction medium after protection of the 5' position has been lifted. |
