Sulfonamides, sulfamates and sulfamides as gamma-secretase inhibitors

A compound of formula I:

• wherein the pyrazole group is attached at one of the positions indicated by an asterisk and X is attached at a position adjacent thereto;
• X represents H, OH, C1-4alkoxy, Cl or F;
• Y represents a bond, O or NR3;
• Ar represents phenyl or 6-membered heteroaryl, either of which bears 0-3 substituents independently selected from halogen, CF3, CHF2, CH2F, NO2, CN, OCF3, C1-6alkyl and C1-6alkoxy;
• R1 represents a hydrocarbon group of 1-5 carbon atoms which is optionally substituted with up to 3 halogen atoms;
• and
• R2 represents a hydrocarbon group of 1-10 carbon atoms which is optionally substituted with up to 3 halogen atoms, or heteroaryl of 5 or 6 ring atoms optionally bearing up to 3 substituents independently selected from halogen, CF3, CHF2, CH2F, NO2, CN, OCF3, C1-6alkyl and C1-6alkoxy;
• or when Y represents NR3, R2 and R3 together may complete a heterocyclic ring of up to 6 members which optionally bears up to 3 substituents independently selected from halogen, CF3, CHF2, CH2F, NO2, CN, OCF3, C1-6alkyl and C1-6alkoxy;
• R3 represents H or C1-4alkyl, or together with R2 completes a heterocyclic ring as defined above;
• or a pharmaceutically acceptable salt thereof.