Excitatory amino acid receptor antagonists

A compound of formula ##STR11## in which R represents a group of formula --L--Q in which

• L represents a bond or a diradical of formula --(CH.sub.2).sub.m (Z.sup.1).sub.p (CH.sub.2).sub.n --
• in which
• m is 1 to 10;
• p is 0 or 1;
• n is 0 to 6;
• and
• Z.sup.1 is oxygen, sulphur or a group of formula NR.sup.a in which R.sup.a represents hydrogen, (1-6C)alkyl or phenyl(1-3C)alkyl;
• and
• Q is hydrogen, an unsubstituted or substituted heteroaromatic group, an unsubstituted or substituted aromatic group, a non-aromatic carbocyclic group, a non-aromatic heterocyclic group, or a non-aromatic monocyclic carbocyclic group fused with one or two monocyclic aromatic or heteroaromatic groups, a non-aromatic monocyclic heterocyclic group fused with one or two monocyclic aromatic or heteroaromatic groups;
• or a group of formula --C(R.sup.1 R.sup.2 R.sup.3)
• in which R.sup.1 represents (1-6C)alkyl, an unsubstituted or substituted heteroaromatic group, an unsubstituted or substituted aromatic group, a non-aromatic carbocyclic group, a non-aromatic heterocyclic group, a non-aromatic monocyclic carbocyclic group fused with one or two monocyclic aromatic or heteroaromatic groups, or a non-aromatic monocyclic heterocyclic group fused with one or two monocyclic aromatic or heteroaromatic groups;
• one or both of R.sup.2 and R.sup.3 is as defined for R.sup.1 or represents a group of formula --Z.sup.2 --R.sup.4 in which Z.sup.2 represents a bond, O, S, CH.sub.2 or --NR.sup.b -- in which R.sup.b represents hydrogen, (1-6C) alkyl or phenyl(1-3C)alkyl, and R.sup.4 represents an unsubstituted or substituted heteroaromatic group or an unsubstituted or substituted aromatic group;
• and the other of R.sup.2 and R.sup.3, if any, represents hydrogen;
• provided that when Q represents hydrogen, L does not represent a bond or methylene;
• or a pharmaceutically acceptable metabolically labile ester or amide thereof;
• or a pharmaceutically acceptable salt thereof.