Heterocyclic compounds

A compound of the general formula (M1)n-Q-(M2)1-n-L-A Iwherein: n is 0 or 1; M1 is an amino group; Q is an aromatic heterocyclic group containing a basic nitrogen atom; M2 is an imino group; L is a template group; and A is an acidic group, or an ester or amide derivative thereof, or a sulphonamide group; and pharmaceutically acceptable salts and pro-drugs thereof, for use in the treatment of a disease in which platelet aggregation mediated by the binding of adhesion molecules to GPIIb-IIIa is involved and the optically active compound (-)-(3R)-3-methyl-4-{4-[4-(4-pyridyl)-piperazin-1-yl]phenoxy}butyric acid is also disclosed.