Combination of cyclohexane and piperazine based κ-opioid receptor agonists: Synthesis and pharmacological evaluation of trans,trans-configured perhydroquinoxalines
摘要:
Desymmetrization of the pseudochiral (2r)-configured cyclohexane-1,2,3-triamines 8 with dimethyl oxalate led to racemic aminoquinoxaline-2,3-diones 9. Selective introduction of the kappa pharmacophoric structural elements pyrrolidine and 3,4-dichlorophenylacetamide with a two-carbon distance afforded conformationally restricted kappa agonists 13-15 based on the quinoxaline ring system. In competitive radioligand receptor binding studies the benzylamine 13b, the secondary amine 14b, and the carbamate 15 displayed high kappa receptor affinity. The K-1 value of the lead compound derived methoxycarbonyl derivative 15 is 9.7 nM. However, the x affinity of 15 is exceeded by 13b and 14b with a basic functional group instead of the methoxycarbonyl group in 1-position of the quinoxaline system. The chlorine atoms of the dichlorophenylacetyl residue are essential, since the corresponding phenylacetyl analogs show considerably reduced x affinity. The potent kappa ligands 13b, 14b and 15 are selective over the related mu- and delta-opioid receptors, sigma(1), sigma(2) and NMDA receptors. In the [S-35]GTP gamma S-binding assay 13b behaved as partial agonist with lower activity than U-69,593. (C) 2014 Elsevier Ltd. All rights reserved.
Combination of cyclohexane and piperazine based κ-opioid receptor agonists: Synthesis and pharmacological evaluation of trans,trans-configured perhydroquinoxalines
摘要:
Desymmetrization of the pseudochiral (2r)-configured cyclohexane-1,2,3-triamines 8 with dimethyl oxalate led to racemic aminoquinoxaline-2,3-diones 9. Selective introduction of the kappa pharmacophoric structural elements pyrrolidine and 3,4-dichlorophenylacetamide with a two-carbon distance afforded conformationally restricted kappa agonists 13-15 based on the quinoxaline ring system. In competitive radioligand receptor binding studies the benzylamine 13b, the secondary amine 14b, and the carbamate 15 displayed high kappa receptor affinity. The K-1 value of the lead compound derived methoxycarbonyl derivative 15 is 9.7 nM. However, the x affinity of 15 is exceeded by 13b and 14b with a basic functional group instead of the methoxycarbonyl group in 1-position of the quinoxaline system. The chlorine atoms of the dichlorophenylacetyl residue are essential, since the corresponding phenylacetyl analogs show considerably reduced x affinity. The potent kappa ligands 13b, 14b and 15 are selective over the related mu- and delta-opioid receptors, sigma(1), sigma(2) and NMDA receptors. In the [S-35]GTP gamma S-binding assay 13b behaved as partial agonist with lower activity than U-69,593. (C) 2014 Elsevier Ltd. All rights reserved.