72782-05-9Relevant academic research and scientific papers
Importance of C-6 chirality in conferring irreversible opioid antagonism to naltrexone-derived affinity labels
Sayre,Larson,Fries,Takemori,Portoghese
, p. 1229 - 1235 (1983)
A series of five epimeric pairs of naltrexone derivatives that contain an electrophilic substituent at the 6α- or 6β-position was synthesized and tested on the guinea pig ileal longitudinal muscle (GPI) and mouse vas deferens (MVD) preparations in order to determine if the orientation of the electrophile is important for covalent bonding to opioid receptors. In the GPI all compounds were pharmacologically active as reversible agonists, but only the 6β-isomers of the fumaramate ester 2b (β-FNA) and isothiocyanate 6b exhibited covalent reactivity, involving a selective irreversible antagonism of the μ agonist, morphine, without affecting κ agonists. The 6α-isomer 2a (α-FNA) was itself nonalkylating but was able to protect the GPI against alkylation by its epimer, β-FNA, indicating that the two epimers bind to the same receptor. These results suggest that the proper orientation of the electrophilic substituent is required for covalent bonding with a proximal nucleophile in the case of μ receptor blockade. Moreover, the lack of covalent bonding to κ receptors by these or other ligands in this series indicates the possible absence of sufficiently reactive nucleophiles on this recognitition site. In the MVD, 2b, but not 2a, irreversibly antagonized morphine (as in GPI), whereas neither epimer exhibited irreversible antagonism toward the δ agonist, [D-Ala2-D-Leu5]enkephalin (DADLE). In contrast, both of the isothiocyanate epimers (6a,b) irreversibly blocked μ and δ receptors. Evidence suggesting differences between μ receptors in the MVD and GPI was obtained with the β-iodoacetamide 5b, which was an irreversible blocker of morphine only in the MVD. When analyzed together with those of previous studies with the nitrogen mustard analogues, α- and β-chlornaltrexamine, the data suggest that the receptor-alkylating ability of each isomer in an epimeric pair differs most when the electrophile possesses a narrow spectrum of reactivity.
Potential irreversible ligands for opioid receptors. Cinnamoyl derivatives of β-naltrexamine
Derrick, Jan,Lewis, John W.,Moynihan, Humphrey A.,Broadbear, Jillian,Woods, James H.
, p. 192 - 196 (2007/10/03)
Cinnamoyl derivatives of β-naltrexamine (β-NTA) have been prepared and evaluated as potential irreversible opioid antagonists. In receptor binding assays, isolated tissue preparations and mouse antinociception assays the p-methylcinnamoyl derivative BU42
