主权项 |
1. A compound of formula (I) wherein: R1 is C3-5 alkyl optionally substituted by one or more halogen atoms; R2 is a phenyl group, optionally substituted by one or more fluorine atoms; R3 and R4 are both hydroxy; R is XOH, where X is CH2, OCH2CH2 or a bond; or a pharmaceutically acceptable salt or solvate thereof, or a solvate of such a salt provided that: when X is CH2 or a bond, R1 is not propyl. when X is CH2 and R1 is CH2CH2CF3, butyl or pentyl, the phenyl group at R2 must be substituted by fluorine. when X is OCH2CH2 and R1 is propyl, the phenyl group at R2 must be substituted by fluorine. |