Patent ID: 7507721

Claim:
A compound of formula wherein X is a —C(═O)—, —C(═O)—O—, —C(═O)—N—, —SO 2 — or —SO 2 —N group; R is a hydrogen atom or methyl; R 1 is a hydrogen atom or a (C 1 -C 3 )-alkyl group; R 2 is a hydrogen atom, a (C 1 -C 4 )-alkoxy-(C 1 -C 4 )-alkyl group, a (C 5 -C 7 )-cycloalkyl group, a phenyl or a five- or six-membered heteroaryl having from one to three heteroatoms selected among nitrogen, oxygen and sulphur, a phenyl-(C 1 -C 4 )-alkyl or heteroaryl-(C 1 -C 4 )-alkyl group optionally substituted by 1 to 3 substituents selected among a (C 1 -C 4 )-alkyl group, a (C 1 -C 4 )-alkoxy group and halogen, or a chain of formula —(CH 2 ) r —Y—(CH 2 ) m -A wherein A is a phenyl or a five- or six-membered heteroaryl having from one to three heteroatoms selected among nitrogen, oxygen and sulphur, both ones optionally substituted by 1 to 3 substituents selected among a (C 1 -C 4 )-alkyl group, a (C 1 -C 4 )-alkoxy group or halogen; Y represents O, S or NR 6 wherein R 6 is a hydrogen atom, a linear or branched (C 1 -C 3 ) alkyl, a (C 1 -C 3 )-alkoxycarbonyl group or a benzyloxycarbonyl group; r is an integer from 1 and 3; m is an integer from 0 and 3; R 3 is a hydroxy group or R 3 taken together with R 4 forms a (═O) group or a ═N—O—R 5 group wherein R 5 is a hydrogen atom, a (C 1 -C 4 )-alkyl group, a benzyl or a —X—R 2 group wherein X and R 2 have the corresponding meanings defined above; R 4 is a hydrogen atom or R 4 taken together with R 3 forms a (═O) group or a ═N—O—R 5 group wherein R 5 has the meanings defined above; and furthermore R 2 is a (C 1 -C 10 )-alkyl group or a (C 4 -C 10 )-alkyl group when, at the same time, X is a —C(═O)— group, R 1 is a (C 1 -C 3 )-alkyl group and R 3 is a hydroxy group or R 3 taken together with R 4 forms a ═N—O—R 5 group wherein R 5 is different from —X—R 2 ; and pharmaceutically acceptable salts thereof.