A compound selected from 14-O-[((Alkyl-, cycloalkyl-, heterocycloalkyl-, heteoroaryl-, or aryl)-sulfanyl)-acetyl]-12-epi-mutilins, or 14-0-[((Alkyl-, cycloalkyl-, heterocycloalkyl-, heteoroaryl-, or aryl)-oxy)-acetyl]-12-epi-mutilins, wherein 12-epi-mutilin is characterized in that the mutilin ring at position 12 is substituted by two substituents, the first substituent at position 12 of the mutilin ring is a methyl group which methyl group has the inverse stereochemistry compared with the stereochemistry of the methyl group at position 12 of the naturally occurring pleuromutilin ring, the second substituent at position 12 of the mutilin ring is a hydrocarbon group comprising at least one nitrogen atom and all other substituents of the mutilin ring having the same stereochemistry compared with the stereochemistry of the substituents at the corresponding positions in the naturally occurring pleuromutilin ring； optionally in the form of a salt and/or solvate, wherein the naturally occurring pleuromutilin is of formula PLEU, processes for the preparation of such compounds and their use as pharmaceuticals.
