SYNTHESIS OF 1,4-DISUBSTITUTED-2-METHYLPIPERAZINES AND STUDY OF THEIRANALGESIC PROPERTIES

A series of N,N-disubstituted-2-methylpiperazines (3a-e) has been synt hesized and compounds tested both in vitro and in vivo for their analg esic properties. Binding studies showed that the new compounds are dev oid of relevant affinity towards mu receptors. However, compound 3a di splayed significant analgesic properties both in the hot plate test an d in the mouse phenyl-p-benzoquinone induced abdominal constriction te st (MAC), whereas the other derivatives were found active only in MAC test. Moreover, it should be noted that compound 3a elicited a Straub- tail reaction also at the lowest administered dose (10 mg/kg, ip) and this effect was antagonized by naloxone.