'Click' D1 receptor agonists with a 5-HT1A receptor pharmacophore producing D2 receptor activity

A series of new 1-aryl-3-benzazepine derivatives containing an arylpiperazinyl function as the N3 substituent were synthesized by combining a D-1 receptor agonistic pharmacophore and a 5-HT1A receptor pharmacophore through Click reaction. Interestingly, these compounds generally do not have good binding affinity at the D-1 receptor, but most compounds are potent at both D-2 and 5-HT1A receptors. Compound 8h, containing 1-m-tolyl-benzazepine scaffold and 2-methoxyphenylpiperazine core, displayed good affinity at all tested receptors, with K-i values of 144, 80, and 133 nM, for the D-1, D-2, and 5-HT1A receptors, respectively. Compound 13 with the triazole moiety formed differently from that in 8h showed the highest affinity at the D-2 receptor with K-i value of 19 nM. This compound also showed moderate affinity at the 5-HT1A (K-i, 105 nM), and D-1 (K-i, 551 nM) receptors. Functional assays indicated that both compounds 13 and 8h are antagonists at D-1 and D-2 receptors, whereas full agonistic activity at the 5-HT1A receptor was observed. In agreement with the binding affinity, compound 13 is a high efficacy D-2 antagonist and 5-HT1A agonist. (C) 2009 Elsevier Ltd. All rights reserved.