Fused tricyclic heteroaromatic derivatives as dopamine receptor subtype ligands

A compound of formula I, or a pharmaceutically acceptable salt thereof or a prodrug thereof:

• ##STR12## wherein the broken circle represents two non-adjacent double bonds whereby the five-membered ring containing X and Y is aromatic;
• one of X and Y represents nitrogen, and the other of X and Y represents N--R.sup.2 ;
• Z represents a chemical bond, an oxygen or sulphur atom, or a methylene group;
• Q represents a moiety selected from the group consisting of a moiety of formulae Qa, Qb, Qc and Qd:
• ##STR13## in which the broken line represents an optional chemical bond;
• V represents an oxygen atom or a moiety of formula N--R.sup.7 ;
• R.sup.6 represents hydrogen, or an optionally substituted C.sub.1-6 alkyl, C.sub.1-6 alkoxy, C.sub.2-6 alkenyl, C.sub.2-6 alkynyl, C.sub.3-7 cycloalkyl, C.sub.3-7 cycloalkyl(C.sub.1-6)alkyl, aryl, aryl(C.sub.1-6)alkyl, aryl(C.sub.1-6)alkoxy, aryl(C.sub.2-6)alkenyl, aryl(C.sub.2-6)alkynyl, C.sub.3-7 heterocycloalkyl(C.sub.1-6)alkyl, heteroaryl, heteroaryl(C.sub.1-6)alkyl, heteroaryl(C.sub.2-6)alkenyl or heteroaryl(C.sub.2-6)alkynyl group, wherein aryl is selected from phenyl or naphthyl and heteroaryl is selected from the group consisting of pyridyl, quinolyl, isoquinolyl, pyridazinyl, pyrimidinyl, pyrazinyl, pyranyl, furyl, benzofuryl, dibenzofuryl, thienyl, benzthienyl, indolyl, imidazolyl, oxadiazolyl and thiadiazolyl;
• R.sup.7 represents an optionally substituted C.sub.1-6 alkyl, C.sub.1-6 alkoxy, C.sub.2-6 alkenyl, C.sub.2-6 alkynyl, C.sub.3-7 cycloalkyl, C.sub.3-7 cycloalkyl(C.sub.1-6)alkyl, aryl, aryl(C.sub.1-6)alkyl, aryl(C.sub.1-6)alkoxy, aryl(C.sub.2-6)alkenyl, aryl(C.sub.2-6)alkynyl, C.sub.3-7 heterocycloalkyl(C.sub.1-6)alkyl, heteroaryl, heteroaryl(C.sub.1-6)alkyl, heteroaryl(C.sub.2-6)alkenyl or heteroaryl(C.sub.2-6)alkynyl group, wherein aryl and heteroaryl are defined above;
• W represents --CH.sub.2 -- or --CH.sub.2 CH.sub.2 --;
• and
• R.sup.8 represents hydrogen, C.sub.1-6 alkyl, C.sub.1-6 alkoxy, aryl, aryl(C.sub.1-6)alkyl, or halogen;
• R.sup.1 and R.sup.2 independently represent hydrogen or C.sub.1-6 alkyl;
• R.sup.3, R.sup.4 and R.sup.5 independently represent hydrogen, hydrocarbon, a heterocyclic group, halogen, cyano, trifluoromethyl, nitro, --OR.sup.a, --SR.sup.a, --SOR.sup.a, SO.sub.2 R.sup.a, --SO.sub.2 NR.sup.a R.sup.b, --NR.sup.a R.sup.b, --NR.sup.a COR.sup.b, --NR.sup.a CO.sub.2 R.sup.b, --COR.sup.a, --CO.sub.2 R.sup.a or --CONR.sup.a R.sup.b ;
• and
• R.sup.a and R.sup.b independently represent hydrogen, hydrocarbon or a heterocyclic group.