Synthesis and pharmacological evaluation of novel cis and trans 3-substituted anilidopiperidines.

BACKGROUND: 4-Anilidopiperidine class of synthetic opioid analgesics, with it's representative fentanyl, are by far the most potent and clinically significant for the treatment of the severe chronic and surgical pain. However, side effects of µ-opioids are often quite serious. In order to improve the pharmacological profile of this class of opioid analgesics, a novel fentanyl analogs were designed, synthesized and evaluated in vivo for their antinociceptive activity. METHODS: The title compounds were prepared using known synthetic transformations, including N-bromoacetamide mediated Hofmann rearrangement, highly selective carbamate cleavage with trimethylsilyl iodide and dehydration of carboxamide group to nitrile in the presence of SOCl2. The antinociceptive activity of the synthesized compounds was determined by tail-immersion and formalin test. RESULTS: The scalable synthetic route towards novel fentanyl analogs bearing nitrogen groups in position C3 of piperidine ring is designed. In addition, Hofmann rearrangement was substantially improved for the more efficient synthesis of previously published 3-substituted fentanyl analogs. The series of ten fentanyl analogs was tested in vivo for their antinociceptive activity. The most potent compound of the series was found to be cis-4, based on the determined ED50 values in tail-immersion test. CONCLUSION: Of ten compounds tested for their antinociceptive activity, compound cis-4 is characterized by high potency, rapid beginning and short duration of action and due to this might be incorporated in different pharmaceutical forms.

α-Glucosidase inhibitory activity and cytotoxic effects of some cyclic urea and carbamate derivatives.

The inhibitory activities of selected cyclic urea and carbamate derivatives (1-13) toward α-glucosidase (α-Gls) in in vitro assay were examined in this study. All examined compounds showed higher inhibitory activity (IC50) against α-Gls compared to standard antidiabetic drug acarbose. The most potent was benzyl (3,4,5-trimethoxyphenyl)carbamate (12) with IC50 = 49.85 ± 0.10 µM. In vitro cytotoxicity of the investigated compounds was tested on three human cancer cell lines HeLa, A549 and MDA-MB-453 using MTT assay. The best antitumour activity was achieved with compound 2 (trans-5-phenethyl-1-phenylhexahydro-1H-imidazo[4,5-c]pyridin-2(3H)-one) against MDA-MB-453 human breast cancer cell line (IC50 = 83.41 ± 1.60 µM). Cyclic ureas and carbamates showed promising anti-α-glucosidase activity and should be further tested as potential antidiabetic drugs. The PLS model of preliminary QSAR study indicated that, in planing the future synthesis of more potent compounds, the newly designed should have the substituents capable of polar interactions with receptor sites in various positions, while avoiding the increase of their lipophilicity.

Docking studies suggest ligand-specific delta-opioid receptor conformations.

An automated docking procedure was used to study binding of a series of delta-selective ligands to three models of the delta-opioid receptor. These models are thought to represent the three ligand-specific receptor conformations. Docking results are in agreement with point mutation studies and suggest that different ligands--agonists and antagonists--may bind to the same binding site under different receptor conformations. Docking to different receptor models (conformations) also suggests that by changing to a receptor-specific conformation, the receptor may open or close different binding sites to other ligands.