abstract |
The present invention relates to a new one-pot process for preparing 2'-(diethylamino)rifamycin P and its 25-desacetyl derivative of formula (I) which consists in cyclizing 3-bromorifamycin S or its 25-desacetyl derivative of formula (II), dissolved in dimethylformamide, with 1,1-diethylthiourea and reducing, without isolation, the obtained 1,2-quinonimine intermediate of formula (III) with a mild reducing agent. <CHEM> a |