abstract |
A compound of formula (I) and pharmaceutically acceptable salts,solvates and hydrolysable esters thereof Formula I:(I); wherein X1 represents O or S; R?1 and R2¿ are independently H or C¿1-3? alkyl or R?1 and R2¿ which are bonded to the same carbon atom may together with the carbon atom to which they are bonded form a 3-5 membered cycloalkyl ring; R?3 and R4¿ independently represent H, Halogen, -CH¿3? and OCH3_; R?5¿ represents H or C¿1-6? alkyl X2 represents NH, NCH3 or O; One of Y and Z is N, and the other is O or S; R?6¿ represents phenyl or pyridyl (wherein the N is in position 2 or 3) and is optionally substituted by one or more halogen, CF¿3?, C1-6 straight or branched alkyl (optionally substituted by halogen), with the provision that when R?6¿ is pyridyl, the N is unsubstituted. |