New derivatives of pleuromutilin, methods for their manufacture, pharmaceutical compound containing such derivatives as well as their application for the manufacture of antimicrobials

Derivatives of pleuromutilin in which the glycolic ester moiety at position 14 is replaced by R 2 (CH 2 ) m X(CH 2 ) n CH 2 COO are of use in antimicrobial therapy. In which: each of n and m is independently 0, 1 or 2; X is selected from -O-, -S-, -S(O)-, -SO 2 -, -CO.O-, -NH-, -CONH-, -NHCONH- and a bond;R 1 is vinyl or ethyl;R 2 is a non-aromatic monocyclic or bicyclic group containing one or two basic nitrogen atoms and attached through a ring carbon atom; R 3 is H or OH; or the moiety R 2 (CH 2 ) m X(CH 2 ) n CH 2 COO at position 14 of (IA) or (IB) is replaced by R a R b C=CHCOO in which one of R a and R b is hydrogen and the other is R 2 or R a and R b together form R 2 ; or a pharmaceutically acceptable salt thereof