METHOD FOR THE PREPARATION OF RIFAMYCIN AF AND ITS DERIVATIVES

摘要

The method is applicable in the pharmaceutical industry for direct preparation of rifamycin AF and its derivatives from rifamycin O with higher yield and purity. The method skips the interim insulation of rifamycin S. Rifamycin O is washed with low alcohol, hydrolysed with protonic acid in chlorinated hydrocarbon and alcohol, followed by preparation of rifamycin S through oxidation with manganese dioxide in the presence of tert.butylamine and N-methylene tert.butylamine. Rifamycin AF is prepared through acidic washing, reduction and hydrolysis with solutions of ascorbic and mineral acid. After washing with water, the prepared rifamycin AF can be crystallized from isopropanol or condensed with the respective radical for preparation of semisynthetic rifamycin.