Abstract: The present invention relates to novel prodrugs of MPV-2426, to methods for preparing said pradrug forms, to pharmaceutical compositions containing such prodrug forms, and to methods for using the prodrug forms. A compound of general formula (1), or pharmaceutically acceptable salts or hydrates thereof, wherein R represents unsubstituted or unsubstituted lower alkyl, ursubstituted or substituted aryl, unsubstituted or substituted cycloalkyl, unsubstuted or substituted hetertoaryl unsubstituted or substituted lower- alkylamine of asaturated five or six membered heterocyclic group containing one or two nitrogen atoms.