Design, synthesis, and anti-allergic activities of novel (R)(-)-1-[(4-chlorophenyl)phenyl methyl]piperazine derivatives

A series of novel (R)(-)-1-[(4-chlorophenyl)phenylmethyl]piperazine derivatives were designed, synthesized, and tested for in vivo anti-allergic activities. Most of these derivatives exhibited significant effects on both allergic asthma and allergic itching. Three of the 19 piperazine derivatives (namely, 3d, 3i, and 3r) have stronger potency against allergic asthma than levocetirizine, the positive control drug. Meanwhile, in the test of allergic itching, five of the 19 compounds (namely, 3b, 3g, 3k, 3o, and 3s) have more potent activities than levocetirizine.