Oxime derivatives

An oxime derivative of the formula I ##STR14## wherein R.sup.4 is hydrogen, carboxy, carbamoyl, amino, cyano, trifluoromethyl, (1-4C)alkylamino, di-(1-4C)alkylamino, (1-4C)alkyl, (2-5C)alkanoyl, (1-4C)alkoxycarbonyl, N-(1-4C)alkylcarbamoyl, N,N-di-(1-4C)alkylcarbamoyl, (1-4C)alkylthio, (1-4C)alkylsulphinyl, (1-4C)alkylsulphonyl, hydroxy-(1-4C)alkyl, (1-4C)alkoxy-(1-4C)alkyl, (1-4C)alkylthio(1-4C)alkyl, phenyl, phenyl-(1-4C)alkyl or heteroaryl and wherein each phenyl or heteroaryl group may optionally bear one or two substituents selected from hydroxy, amino, halogeno, cyano, trifluoromethyl, (1-4C)alkyl, (1-4C)alkoxy, (1-4C)alkylamino, di-(1-4C)alkyamino, (1-4C)alkylthio, (1-4C)alkylsulphinyl and (1-4C)alkylsulphonyl;

• R.sup.5 is hydrogen, (1-4C)alkyl, (3-4C)alkenyl, (3-4C)alkynyl, (2-5C)alkanoyl, halogeno-(2-4C)alkyl, hydroxy-(2-4C)alkyl, (1-4C)alkoxy-(2-4C)alkyl, carbamoyl, N-(1-4C)alkylcarbamoyl, N,N-di-(1-4C)alkylcarbamoyl, amino-(2-4C)alkyl, (1-4C)alkylamino-(2-4C)alkyl, di-(1-4C)alkylamino-(2-4C)alkyl, (1-4C)alkylthio-(2-4C)alkyl, (1-4C)alkylsulphinyl-(2-4C)alkyl, (1-4C)alkylsulphonyl-(2-4C)alkyl, cyano-(1-4C)alkyl, carboxy-(1-4C)alkyl, (1-4C)alkoycarbonyl-(1-4C)alkyl, carbamoyl-(1-4C)alkyl, N-(1-4C)alkylcarbamoyl-(1-4C)alkyl, N,N-di-(1-4C)alkylcarbamoyl-(1-4C)alkyl, (2-5C)alkanoylamino-(2-4C)alkyl, (2-5C)alkanoyl-(1-4C)alkyl, phenyl-(1-4C)alkyl, heteroaryl-(1-4C)alkyl or heteroarylthio(2-4C)alkyl and wherein each phenyl or heteroaryl group may optionally bear one or two substituents selected from halogeno, cyano, trifluoromethyl, carboxy, (1-4C)alkyl, (1-4C)alkoxy, (1-4C)alkoxycarbonyl, carboxy-(1-4C)alkyl and (1-4C)alkoxycarbonyl-(1-4C)alkyl;
• and wherein said heteroaryl group in R.sup.4 or R.sup.5 is a 5-membered or 6-membered heterocyclic moiety containing up to four nitrogen heteroatoms and optionally containing a further heteroatom selected from oxygen and sulphur;
• Ar.sup.1 is phenylene or a 6-membered heteroaryl diradical containing one or two nitrogen heteroatoms which may optionally bear one or two substituents selected from halogeno, cyano, trifluoromethyl, hydroxy, amino, (1-4C)alkyl, (1-4C)alkoxy, phenyl-(1-4C)alkoxy, (1-4C)alkylamino and di-(1-4C)alkylamino;
• A.sup.1 is a direct link to X.sup.1, or A.sup.1 is (1-4C)alkylene;
• X.sup.1 is oxy, thio, sulphinyl or sulphonyl;
• Ar.sup.2 is phenylene, pyridinediyl, pyrimidinediyl, thiophenediyl, furandiyl, thiazolediyl, oxazolediyl, thiadiazolediyl or oxadiazolediyl which may optionally bear one or two substituents selected from halogeno, cyano, trifluoromethyl, hydroxy, amino, (1-4C)alkyl, (1-4C)alkoxy, (1-4C)alkylamino and di-(1-4C)alkylamino;
• R.sup.1 is (1-4C)alkyl, (3-4C)alkenyl or (3-4C)alkynyl;
• and R.sup.2 and R.sup.3 together form a group of the formula -A.sup.2 -X.sup.2 -A.sup.3 -which together with the carbon atom to which A.sup.2 and A.sup.3 are attached define a ring having 5 or 6 ring atoms, which each of A.sup.2 and A.sup.3 is independently (1-3C)alkylene and X.sup.2 is oxy, and which ring may optionally bear one or two substituents selected from hydroxy, (1-4C)alkyl and (1-4C)alkoxy;
• or a pharmaceutically-acceptable salt thereof.