Patent ID: 7045653

Claim:
A compound of formula (I), a pharmaceutically acceptable salt or solvate thereof wherein R 1 is C 1 –C 6 alkyl, C 1 –C 6 alkoxyC 1 –C 3 alkyl or C 1 –C 6 alkoxyC 1 –C 6 alkoxyC 1 –C 3 alkyl; R 2 is hydrogen or C 1 –C 6 alkyl; L is a three atom linkage selected from —CH 2 —X—CH 2 — and —CH 2 —CH 2 —X— where the right hand side of the linkage is attached to R 3 and where X is oxygen or methylene; R 3 is phenyl which may be independently substituted by one or more groups selected from: C 1 –C 6 alkyl, halo, haloC 1 –C 6 alkyl, C 1 –C 6 alkoxy, haloC 1 –C 6 alkoxy, C 1 –C 6 alkylthio, haloC 1 –C 6 alkylthio and nitrile; and R 4 and R 5 are either both hydrogen or one of R 4 and R 5 is hydrogen and the other is a biolabile ester-forming group selected from: i) C 1 –C 6 alkyl optionally substituted by hydroxy, oxo, halo, haloC 1 –C 6 alkyl, C 1 –C 6 alkoxy, haloC 1 –C 6 alkoxy, C 1 –C 6 alkylthio haloC 1 –C 6 alkylthio, nitrile, carbocyclyl, carbocyclyloxy, alkylcarbonyloxy, carbocyclylcarbonyloxy, alkylcarbonylamino, or alkylaminocarbonyl, wherein any carbocyclyl group is optionally substituted by C 1 –C 6 alkyl, halo, haloC 1 –C 6 alkyl, C 1 –C 6 alkoxy, haloC 1 –C 6 alkoxy, C 1 –C 6 alkylthio, haloC 1 –C 6 alkylthio or nitrile; or ii) carbocyclyl optionally substituted by C 1 –C 6 alkyl, halo, haloC 1 –C 6 alkyl, C 1 –C 6 alkoxy, haloC 1 –C 6 alkoxy, C 1 –C 6 alkylthio, haloC 1 –C 6 alkylthio or nitrile.