The present invention relates to the compounds of formula (I): ##STR00001## in which A is a group of formula (a) or (b) ##STR00002## in which R represents a hydrogen or halogen atom, an --S(O).sub.z(C.sub.1-C.sub.4)alkyl group, an --NHSO.sub.2(C.sub.1-C.sub.4)alkyl group, an --SO.sub.2NH(C.sub.1-C.sub.4)alkyl group, an --NHSO.sub.2phenyl-(C.sub.1-C.sub.4)alkyl group or an --NHSO.sub.2phenyl group, said phenyl possibly being substituted with a halogen atom, with a (C.sub.1-C.sub.4)alkyl group or with a (C.sub.1-C.sub.4)alkoxy group; R.sub.1 represents a hydrogen atom or a (C.sub.1-C.sub.4)alkyl group, a --CO(C.sub.1-C.sub.4)alkyl group, a phenyl-(C.sub.1-C.sub.4)alkyl group or a --COphenyl group, said phenyl also possibly being substituted with a halogen atom or with a (C.sub.1-C.sub.4)alkoxy group; R.sub.2 is a hydrogen atom or an --SO.sub.2(C.sub.1-C.sub.4)alkyl group, an --SO.sub.2phenyl-(C.sub.1-C.sub.4)alkyl group or an --SO.sub.2phenyl group; X completes a ring of 5 to 8 atoms, said ring being saturated or unsaturated, possibly being substituted with one or two (C.sub.1-C.sub.4)alkyl groups and bearing one or two carbonyl groups; n, m and z are, independently, 0, 1 or 2; R.sub.3 represents a hydrogen or halogen atom, a (C.sub.1-C.sub.6)alkyl group, a (C.sub.1-C.sub.4)alkoxy group, a --COO(C.sub.1-C.sub.4)alkyl group, a --CO(C.sub.1-C.sub.4)alkyl group, an --NHSO.sub.2(C.sub.1-C.sub.4)alkyl group, an --NHSO.sub.2phenyl-(C.sub.1-C.sub.4)alkyl groups, --NO.sub.2, --CN, --CONR.sub.4R.sub.5, --COOH, or a 4,5-dihydro-1,3-oxazol-2-yl or 4,4-dimethyl-4,5-dihydro-1,3-oxazol-2-yl group; R.sub.4 and R.sub.5 represent, independently, a hydrogen atom, a phenyl, a (C.sub.1-C.sub.4)alkyl group or a phenyl-(C.sub.1-C.sub.4)alkyl group or R.sub.4 and R.sub.5 with the nitrogen atom to which they are attached, may form a ring of 5 to 7 atoms in total; and to the salts or solvates thereof, to the pharmaceutical compositions containing them, to a process for the preparation thereof and to intermediates in this process.