NOUVELLES (PIPERAZINYL 4-SUBSTITUE) PYRIDAZINES UTILES NOTAMMENT COMME MEDICAMENTS ANALGESIQUES ET ANTITUSSIFS, ET PROCEDE POUR LEUR PREPARATION

NOUVELLES (PIPERAZINYL 4-SUBSTITUE) PYRIDAZINES UTILES NOTAMMENT COMME MEDICAMENTS ANALGESIQUES ET ANTITUSSIFS, ET PROCEDE POUR LEUR PREPARATION ; LES COMPOSES DE L'INVENTION REPONDENT A LA FORMULE (I) OU LES SYMBOLES SONT DEFINIS OU CONSISTENT EN LES N-OXYDES, LES SELS D'ADDITION D'ACIDES CONVENANT EN PHARMACIE OU LES ISOMERES STEREOCHIMIQUES EVENTUELS CORRESPONDANTS Novel (4-substituted-piperazinyl)pyridazines of formula wherein R is hydrogen, halo, C1-6alkyloxy, hydroxy or phenyl; m is the integer 2 or 3; R , R , R and R are, each independently, hydrogen, or C1-6alkyl; or where R and R are substituted on a different carbon atom, R and R taken together, may form a bivalent radical -CH2-CH2-; R is (aryl)C2-6alkenyl, (aryl)C2-6alkynyl, (aryl)(hydroxy)C1-6alkyl or (aryl)(oxo)C1-6alkyl; the N-oxide forms, the pharmaceutically acceptable acid addition salts and the possible stereochemically isomeric forms, which compounds are analgesic and antitussive agents; pharmaceutical compositions containing such compounds as an active ingredient and methods of preparing said compounds and pharmaceutical compositions.