Patent ID: 8420622

Claim:
A compound of formula I: or a pharmaceutically acceptable salt thereof; wherein: p is 0, 1 or 2; n is 0, 1, 2 or 3; the moiety —C(R 1 ) 2 —Z is attached to the 3-, 4- or 5-position of the piperidine ring; Z represents CO 2 H or a tetrazole ring; each R 1 independently represents H or a non-aromatic hydrocarbon group of up to 6 carbon atoms; or the two R 1 groups complete a C 3-6 alicyclic group; each R 2 independently represents a non-aromatic hydrocarbon group of up to 6 carbon atoms; each R 3 independently represents halogen, C 1-6 alkyl bearing 0-3 fluorine substituents, C 1-6 alkoxy bearing 0-3 fluorine substituents, C 2-6 alkenyl, or Si(R 6 ) 3 ; R 4 is selected from: (i) H; (ii) Het-A- where A represents a bond, CH 2 or 1,4-phenylene and Het represents a heterocyclic ring system of up to 10 ring atoms which optionally bears up to 3 substituents selected from halogen, C 1-4 alkyl, CF 3 , Si(R 6 ) 3 , C 1-4 -alkoxy and C 1-4 -alkoxycarbonyl or which optionally bears a phenyl substituent which itself is optionally substituted with halogen, C 1-4 alkyl, Si(R 6 ) 3 , C 1-4 -alkoxy or C 1-4 alkoxycarbonyl; and (iii) hydrocarbon of up to 12 carbon atoms which optionally bears up to 3 substituents selected from halogen, perfluoroC 1-4 alkyl, CN, Si(R 6 ) 3 , OH, C 1-4 -alkoxy and OCF 3 ; R 5 is selected from: (i) H; (ii) hydrocarbon of up to 12 carbon atoms which optionally bears up to 3 substituents selected from halogen, perfluoroC 1-4 -alkyl, CN, Si(R 6 ) 3 , OH, C 1-4 -alkoxy and OCF 3 ; and (iii) CO 2 R 7 where R 7 represents hydrocarbon of up to 12 carbon atoms which optionally bears up to 3 substituents selected from halogen, perfluoroC 1-4 -alkyl, CN, Si(R 6 ) 3 , OH, C 1-4 -alkoxy and OCF 3 ; and each R 6 independently represents a hydrocarbon group of up to 6 carbon atoms; provided R 4 and R 5 do not both represent H and provided at least one of R 4 and R 5 bears Si(R 6 ) 3 as a substituent.