| abstract |
A compound of formula (I) or a metabolically labile salt or ester thereof, characterized in that R represents a group selected from halogen, alkyl, alkoxy, amino, alkylamino, dialkylamino, hydroxyl, trifluoromethyl, trifluoromethoxy, nitro, cyano, SO2 R4 , or COR4, where R4 represents hydroxyl, methoxy, amino, alkylamino or dialkylamino; m is zero or an integer 1 or 2: A represents an ethynyl or ethylenyl group optionally substituted; R1 represents hydrogen or an optionally substituted alkyl, cycloalkyl, aryl or heterocyclic group; R2 represents hydrogen or alkyl; or R1 and R2 together with the nitrogen atom to which they are attached represent a 5- to 7-membered heterocyclic ring, which may contain an additional heteroatom selected from oxygen, sulfur or nitrogen; R3 represents hydrogen or alkyl; n is zero or an integer from 1 to 4. X = O or S. |