COMPOUNDS OF FORMULA (I): IN WHICH: X REPRESENTS AN OPTIONALLY SUBSTITUTED PHENYL GROUP; R1 REPRESENTS A HYDROGEN ATOM, A HALOGEN, A GROUP (C1-C6)ALKOXY, A GROUP (C1-C6)ALKYL OR A GROUP NRARB; R2 REPRESENTS AN OPTIONALLY SUBSTITUTED HETEROCYCLIC GROUP; R3 REPRESENTS A HYDROGEN ATOM, A GROUP (C1- C6)ALKYL, A GROUP (C1-C6)ALKOXY OR A HALOGEN ATOM; R4 REPRESENTS A HYDROGEN ATOM, A GROUP (C1-C4)ALKYL, A GROUP (C1-C4)ALKOXY OR A FLUORINE ATOM, IN THE FORM OF THE BASE OR OF AN ACID-ADDITION SALT. THERAPEUTIC USE.