Isoxazole and pyrazole derivatives as dopamine receptor subtype ligands

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

• ##STR10## 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 other of X and Y represents oxygen or N--R.sup.5 ;
• R.sup.1 represents hydrogen, C.sub.1-6 alkyl or trifluoromethyl;
• R.sup.2 and R.sup.3 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 ;
• wherein hydrocarbon is selected from the group consisting of:
• C.sub.1-6 alkyl, 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 and aryl(C.sub.1-6)alkyl;
• and aryl is phenyl or naphthyl;
• and the heterocyclic group is selected from the group consisting of:
• C.sub.3-7 heterocycloalkyl, C.sub.3-7 heterocycloalkyl(C.sub.1-6)alkyl, heteroaryl and heteroaryl(C.sub.1-6)alkyl;
• wherein heterocycloalkyl is selected from azetidinyl, pyrrolidyl, piperidyl, piperazinyl and morpholinyl groups;
• and heteroaryl is selected from:
• pyridyl, quinolyl, isoquinolyl, pyridazinyl, pyrimidinyl, pyrazinyl, pyranyl, furyl, benzofuryl, dibenzofuryl, thienyl, benzthienyl, indolyl, aza-indolyl, imidazolyl, oxadiazolyl and thiadiazolyl;
• wherein the hydrocarbon and heterocyclic groups can be substituted by one or more groups selected from C.sub.1-6 alkyl, adamantyl, phenyl, aryl(C.sub.1-6)alkyl, halogen, C.sub.1-6 haloalkyl, C.sub.1-6 aminoalkyl, trifluoromethyl, hydroxy, C.sub.1-6 alkoxy, aryloxy, keto, C.sub.1-3 alkylenedioxy, nitro, cyano, carboxy, C.sub.2-6 alkoxycarbonyl, C.sub.2-6 alkoxycarbonyl(C.sub.1-6)alkyl, C.sub.2-6 alkylcarbonyloxy, arylcarbonyloxy, C.sub.2-6 alkylcarbonyl, arylcarbonyl, C.sub.1-6 alkylthio, C.sub.1-6 alkylsulphinyl, C.sub.1-6 alkylsulphonyl, arylsulphonyl, trifluoromethane-sulphonyloxy, --NR.sup.v R.sup.w, --NR.sup.v COR.sup.w, --NR.sup.v CO.sub.2 R.sup.w, --NR.sup.v SO.sub.2 R.sup.w, --CH.sub.2 NR.sup.v SO.sub.2 R.sup.w, --NHCONR.sup.v R.sup.w, --PO(OR.sup.v)(OR.sup.w), --CONR.sup.v R.sup.w, --SO.sub.2 NR.sup.v R.sup.w and --CH.sub.2 SO.sub.2 NR.sup.v R.sup.w, in which R.sup.v and R.sup.w independently represent hydrogen, C.sub.1-6 alkyl, aryl or aryl(C.sub.1-6)alkyl;
• and
• R.sup.4 represents hydrocarbon or a heterocyclic group, as defined above;
• R.sup.5 represents hydrogen or C.sub.1-6 alkyl;
• and
• R.sup.a and R.sup.b independently represent hydrogen, hydrocarbon or a heterocyclic group, as defined above.