'Click' D(1) receptor agonists with a 5-HT(1A) receptor pharmacophore producing D(2) 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-HT(1A) 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-HT(1A) 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 133nM, for the D(1), D(2), and 5-HT(1A) 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 19nM. This compound also showed moderate affinity at the 5-HT(1A) (K(i), 105nM), and D(1) (K(i), 551nM) 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-HT(1A) receptor was observed. In agreement with the binding affinity, compound 13 is a high efficacy D(2) antagonist and 5-HT(1A) agonist.