Alanyl-piperidine heterocyclic derivatives useful against cardiovascular diseases

A compound of formula (I)

• in which
• X1 represents N;
• n is 1 or 2;
• R1 represents trifluoromethyl, COOH, CONH2, SO2NH2, phenyl, pyridyl, C-linked imidazolyl (which may bear an N-(1–4C)alkyl substituent) or a (3–6C)cycloalkyl, oxa (4–6C)cycloalkyl, thia(4–6C)cycloalkyl or C-linked aza (4–6C)cycloalkyl group, which C-linked aza(4–6C)cycloalkyl group may bear an N-(1–4C)alkyl substituent;
• and
• R2 is selected from
• in which
• X2 represents a hydrogen atom, a halogen atom or an amino group;
• X3 represents a hydrogen atom, a methyl group, a fluorine atom, a chlorine atom or a bromine atom;
• X4 represents a hydrogen atom, a methyl, group or a halogen atom;
• X5 represents a chlorine atom, a methoxy group or a methyl group;
• and
• X6 represents a hydrogen atom, a halogen atom or a methyl group;
• or a pharmaceutically acceptable metabolically labile ester thereof, or a pharmaceutically acceptable salt thereof.