Novel compounds

A compound of formula (I) or pharmaceutically acceptable salts thereof,

• wherein
• R1 is H, or halo or C1-4 alkyl;
• R2 is a 4 to 6 membered non-aromatic carbocylic group, or phenyl, or pyridinyl;
• which carbocylic or pyridinyl group is optionally substituted with one or two substituents, which may be the same or different, selected from the group consisting of:
• halo, C1-4 alkyl, C1-4 alkoxy, halo C1-4 alkyl and halo C1-4 alkoxy;
• or which phenyl group is substituted with one or two substituents, which may be the same or different, selected from the group consisting of:
• halo, C1-4 alkyl, C1-4 alkoxy, halo C1-4 alkyl and halo C1-4 alkoxy;
• R3 is halo;
• R4 is COOH, CH2COOH or tetrazolyl;
• X is C or N;
• and
• n is 0 or 1;
• with the proviso that when R4 is in the 4 position on the ring, it cannot be CH2COOH;
• and
• when R4 is in the 3 position on the ring, R2 is not 4-chloro-phenyl.