摘要:
There is continuing interest in the discovery and development of new kappa opioid receptor antagonists. We recently reported that N-substituted 3-methyl-4-(3-hydroxyphenyl)piperazines were a new class of opioid receptor antagonists. In this study, we report the syntheses of two piperazine JDTic-like analogues. Evaluation of the two compounds in an in vitro [S-35]GTP gamma S binding assay showed that neither compound showed the high potency and kappa opioid receptor selectivity of JDTic. A library of compounds using the core scaffold 21 was synthesized and tested for their ability to inhibit [S-35]GTP gamma S binding stimulated by the selective kappa opioid agonist U69,593. These studies led to N-[(1S)-1-{[(3S)-4-(3-hydroxyphenyl)-3-methylpiperazin-1-yl]methyll-2-methylpropyl]-4-phenoxybenzamide (11a), a compound that showed good kappa opioid receptor antagonist properties. An SAR study based on 11a provided 28 novel analogues. Evaluation of these 28 compounds in the [S-35]GTP gamma S binding assay showed that several of the analogues were potent and selective kappa opioid receptor antagonists.