Patent ID: 7582676

Claim:
A compound of formula (I): wherein R 1 represents an alkyl group; R 2 represents a group chosen from alkyl, C 3 -C 7 cycloalkyl, pyridyl, thienyl, naphthyl, tetrahydronaphthyl, indanyl, and a phenyl group; wherein the phenyl group is unsubstituted or substituted by one or more substituents independently chosen from halogen atoms, alkyl, trifluoromethyl, hydroxy, alkoxy, methylthio, amino, mono- and dialkylamino, hydroxyalkyl and hydroxycarbonyl groups; R 3 and R 4 , which may be the same or different, represent, independently of each other, a group chosen from a hydrogen atom, alkyl, alkenyl and alkynyl groups, wherein the alkyl, alkenyl, and alkynyl groups are unsubstituted or substituted by one or more halogen atoms; and X represents a single bond, an oxygen atom, or a methylene group; , or a pharmaceutically acceptable salt thereof, in any enantiomeric form, or a mixture of any such compounds in any ratio.