.gamma.-butyrolactone derivatives, process for preparing the same and

Abstract

A .gamma.-butyrolactone derivative represented by the following formula: ##STR1## wherein R.sup.1 represents a hydrogen atom, a straight or branched alkyl group having 1-8 carbon atoms, a phenyl group; R.sup.2 and R.sup.3 may be the same or different and each represents a hydrogen atom, a straight or branched alkyl group having 1-8 carbon atoms, a cycloalkyl group having 3-10 carbon atoms, a benzyl group, a phenyl group, a phenyl group substituted with a substituent selected from the group consisting of a halogen atom, an alkoxy group, a nitro group, an amino group, an alkyl group having 1-4 carbon atoms, a nitrile group and an alkoxycarbonyl group; R.sup.2 and R.sup.3 may be linked to form an alkylene group having 4-6 carbon atoms; X represents a hydrogen atom, a straight or branched alkyl group having 1-8 carbon atoms, a cycloalkyl group having 3-10 carbon atoms, a benzyl group or a substituent represented by the formula ##STR2## (wherein R.sup.4 represents a straight or branched alkyl group having 1-8 carbon atoms, a cycloalkyl group having 3-10 carbon atoms, a benzyl group, a phenyl group or a phenyl group substituted with a substituent selected from the group consisting of a halogen atom, an alkoxy group, a nitro group, an alkylthio group, a nitrile group, an alkoxycarbonyl group and an alkyl group having 1-4 carbon atoms) or a salt thereof. The invention also provides an immunomodulating composition wherein the aforedescribed compound is the active component.