Structural modifications in the distal, regulatory region of histamine H3 receptor antagonists leading to the identification of a potent anti-obesity agent
concentration range. The most influential modification that affected the affinity toward the H3R appeared by introducing electron-withdrawing moieties into the distal aromaticring. In order to finally discuss the influence of the characteristic 4-pyridylpiperazine moiety on H3R affinity, two Ciproxifan analogues 2 and 3 with a slight modification in their basic part were obtained. The replacement of piperazine
Compounds of the formula: ##STR1## wherein R.sup.1 represents a methyl or ethyl group, R.sup.2 represents a bromine or chlorine atom, and R.sup.3 represents a hydrogen, chlorine, bromine or iodine atom, an alkyl or alkenyl group containing up to 4 carbon atoms, or a cyano or trifluoromethyl group, are new compounds possessing antimalarial properties.