| abstract |
A compound of the formula (I), or a pharmaceutically acceptable salt thereof, or a pharmaceutically acceptable solvate thereof, wherein, X represents a moiety of formula (a), in which A 1 represents --CH═CH═, NH, S or O; A 2 represents an oxo or a thioxo group; A 3 represents H or an alkylcarbonyl group; and A 4 represents hydroxy or NR s R t wherein R s and R t each independently represents H or alkyl; R 0 and R 1 each independently represents hydrogen or an alkyl group; R 2 represents OCH 2 CO 2 H, or an ester or amide thereof, or R 2 represents a moiety of formula (b), wherein R 4 and R 5 each independently represent hydrogen, alkyl, hydroxyalkyl, cycloalkyl or R 4 together with R 5 represents (CH 2 ) n wherein n is 2, 3 or 4; and R 3 represents hydrogen, halogen, alkyl or alkoxy or R 3 together with R 2 represents a moiety of formula (c) or an ester or amide thereof, wherein R represents hydrogen, alkyl, hydroxymethyl or a moiety of formula (CH 2 ) n CO 2 H, wherein n is zero or an integer 1, 2 or 3, or an ester or amide thereof; a process for the preparation of such a compound, a pharmaceutical composition containing such a compound and the use of such a compound and composition in medicine. |