Synthesis and Structure-Activity Relationships of (−)-cis-N-Normetazocine-Based LP1 Derivatives
Abstract(−)-cis-N-Normetazocine represents a rigid scaffold able to mimic the tyramine moiety of endogenous opioid peptides, and the introduction of different N-substituents influences affinity and efficacy of respective ligands at MOR (mu opioid receptor), DOR (delta opioid receptor), and KOR (kappa opioid receptor). We have previously identified LP1, a MOR/DOR multitarget opioid ligand, with an N-phenylpropanamido substituent linked to (−)-cis-N-Normetazocine scaffold. Herein, we report the synthesis, competition binding and calcium mobilization assays of new compounds 10–16 that differ from LP1 by the nature of the N-substituent. In radioligand binding experiments, the compounds 10–13, featured by an electron-withdrawing or electron-donating group in the para position of phenyl ring, displayed improved affinity for KOR (Ki = 0.85–4.80 μM) in comparison to LP1 (7.5 μM). On the contrary, their MOR and DOR affinities were worse (Ki = 0.18–0.28 μM and Ki = 0.38–1.10 μM, respectively) with respect to LP1 values (Ki = 0.049 and 0.033 μM). Analogous trends was recorded for the compounds 14–16, featured by indoline, tetrahydroquinoline, and diphenylamine functionalities in the N-substituent. In calcium mobilization assays, the compound 10 with a p-fluorophenyl in the N-substituent shared the functional profile of LP1 (pEC50MOR = 7.01), although it was less active. Moreover, the p-methyl- (11) and p-cyano- (12) substituted compounds resulted in MOR partial agonists and DOR/KOR antagonists. By contrast, the derivatives 13–15 resulted as MOR antagonists, and the derivative 16 as a MOR/KOR antagonist (pKBMOR = 6.12 and pKBKOR = 6.11). Collectively, these data corroborated the critical role of the N-substituent in (−)-cis-N-Normetazocine scaffold. Thus, the new synthesized compounds could represent a template to achieve a specific agonist, antagonist, or mixed agonist/antagonist functional profile. View Full-Text
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Pasquinucci, L.; Parenti, C.; Amata, E.; Georgoussi, Z.; Pallaki, P.; Camarda, V.; Calò, G.; Arena, E.; Montenegro, L.; Turnaturi, R. Synthesis and Structure-Activity Relationships of (−)-cis-N-Normetazocine-Based LP1 Derivatives. Pharmaceuticals 2018, 11, 40.
Pasquinucci L, Parenti C, Amata E, Georgoussi Z, Pallaki P, Camarda V, Calò G, Arena E, Montenegro L, Turnaturi R. Synthesis and Structure-Activity Relationships of (−)-cis-N-Normetazocine-Based LP1 Derivatives. Pharmaceuticals. 2018; 11(2):40.Chicago/Turabian Style
Pasquinucci, Lorella; Parenti, Carmela; Amata, Emanuele; Georgoussi, Zafiroula; Pallaki, Paschalina; Camarda, Valeria; Calò, Girolamo; Arena, Emanuela; Montenegro, Lucia; Turnaturi, Rita. 2018. "Synthesis and Structure-Activity Relationships of (−)-cis-N-Normetazocine-Based LP1 Derivatives." Pharmaceuticals 11, no. 2: 40.
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