The invention relates to the compounds of general formula (I) ##STR00001## where R.sub.1 represents H, a (C1-C4)alkyl, --CO(C1-C4)alkyl, (C1-C4)alkylphenyl or --CO-phenyl group, said phenyl being optionally substituted, R.sub.2 represents H, a halogen atom, an --S(O).sub.zR.sub.3, --NHSO.sub.2R.sub.3, --NHSO.sub.2-phenyl or --NHSO.sub.2--(C1-C4)alkylphenyl group where z is equal to 0, 1 or 2 and where R.sub.3 represents a (C1-C4)alkyl group, said phenyl being optionally substituted; A is chosen from ##STR00002## where n is equal to 0, 1 or 2, R.sub.4 and R.sub.5 represent H, a (C1-C4)alkyl, hydroxyl, cyano, phenyl, benzyl, piperidyl, --CONH.sub.2, --CO-phenyl, --COOR.sub.3, --CH(phenyl) (OH) and --C(phenyl).sub.2(OH) group, or R.sub.4 and R.sub.5 form together an optionally substituted 6-membered aromatic ring, R.sub.6 represents H, a (C1-C4)alkyl, phenyl or benzyl group, and B represents a 5- or 6-membered nitrogen-containing heterocycle or homocycle optionally fused with a phenyl Group or optionally substituted; their addition salts; their method of preparation and their therapeutic application.