NOVEL METHOD FOR PREPARING CYLOSPORIN DERIVATIVES

摘要

The invention concerns a novel method for preparing a polyanion useful for preparing cyclosporin derivatives modified in position -3 by treating a cyclosporin with an alkali amide in liquid ammonia or in an aliphatic amine of low molecular weight, in the presence of a cosolvent, and optionally in the presence of dimethylpropyleneurea (DMPU). The treated cyclosporin has one or several free hydroxy groups and/or non-methylated nitrogen atoms in position alpha and/or any other acid group capable of being subjected to deprotonation and which are optionally subjected to deprotonation, or are in protected form.