Syntheses and binding affinities of 6-nitroquipazine analogues for serotonin transporter. part 2: 4-Substituted 6-nitroquipazines

Eleven 4-substituted derivatives of 6-nitroquipazine were synthesized and evaluated for their abilities to displace [3H]citalopram binding to the rat cortical synaptic membranes. Among them, 4-chloro-6-nitroquipazine was shown to possess the highest binding affinity (Ki=0.03 nM) which was approximately 6 times higher than that of 6-nitroquipazine (Ki=0.17 nM) itself. In this paper, we describe the syntheses of 4-substituted 6-nitroquipazine derivatives, the results of corresponding biological evaluation and the SAR study.