Compounds

A compound of formula (I) or a salt thereof:

• in which the group D is selected from a group of formula (A), (B) or (C) below:
• in which
• P is a monocyclic alicyclic ring containing 4-10 carbon atoms;
• A is a single bond, a C1-6alkylene or a C2-6alkenylene group;
• R1 is halogen, C1-6alkyl optionally substituted by one or more fluorine atoms, C3-6cycloalkyl, C1-6alkoxy, OCF3, hydroxy, hydroxyC1-6alkyl, hydroxyC1-6alkoxy, C1-6alkoxyC1-6alkoxy, C1-6alkanoyl, amino, alkylamino or dialkylamino, SR11 where R11 is hydrogen or C1-6alkyl or R1 is aryl, or arylC1-6alkyl;
• n is 0, 1, 2 or 3;
• and
• R2 is hydrogen, C1-6alkyl, aryl, arylC1-6alkyl or C3-6cycloalkyl;
• or
• in which Ra is an alkyl group containing 1 to 20 carbon atoms or is an arylC1-6alkyl group, and Rb is hydrogen;
• or
• in which Q is a monocyclic group containing a nitrogen heteroatom bonded to the adjacent SO2 group or Q is a 5 or 6-membered heterocyclic ring containing a nitrogen heteroatom bonded to the adjacent SO2 group and a further heteroatom selected from nitrogen, oxygen or sulphur, and R1 and n are as defined above;
• R3 is a group R5;
• R4 is a piperazine ring optionally substituted by C1-6 alkyl;
• R5 is hydrogen, halogen, C1-6alkyl, C3-6cycloalkyl, C1-6alkoxy optionally substituted with one or more fluorine atoms, hydroxy, hydroxyC1-6alkyl, hydroxyC1-6alkoxy, C1-6alkoxyC1-6alkoxy, C1-6alkanoyl or trifluoromethyl.