Patent ID: 6911451

Claim:
A compound of formula (1a): wherein: R is a carboxylic acid; R 1 is a pyridyl group substituted by one or two halogen atoms; -(Alk 1 ) r (L 1 ) s — is a —CH 2 O— or —CON(R 5 )— group; R 5 is a hydrogen atom or a straight or branched alkyl group; Alk 2 is a straight or branched alkylene chain; m is zero or an integer 1; R 2 is a hydrogen atom or a methyl group; X 1 is a group selected from —N(R 3 )CO—, (where R 3 is a hydrogen atom or a straight or branched alkyl group); —N(R 3 )SO 2 —, —N(R 3 )C(O)O— or —N(R 3 )CON(R 3a )— (where R 3a is a hydrogen atom or a straight or branched alkyl group); R 4 is a straight or branched C 1-6 alkyl group; or a pharmaceutically acceptable salt thereof.