Piperidine Derivatives Research Articles

Synthesis, identification and molecular docking studies of N-functionalized piperidine derivatives linked to 1,2,3-triazole ring

New derivatives of piperidine bearing a 1,2,3-triazole ring designed and synthesized smoothly over six steps from N-protected piperidone-4-one. These steps included reduction of the carbonyl group/tosylation of the resulting alcohol providing tosyl derivative in a good yield, followed by nucleophilic substitution and Cu-catalysed azide-alkyne cycloaddition. By removing the protecting group and functionalizing amine group via reductive amination gave the desired design in moderate to very good yields. Molecular modeling studies of these compounds predicted possible binding modes into the active site of dopamine receptor D2.

Synthesis and Evaluation of Antimicrobial Activities of New Piperidine Derivatives

Nitrogen heterocycles with piperidine rings are the most prominent structural features and frequently utilized by pharmaceuticals. In this study, we have disclosed the synthesis of new compounds with piperidine motif. The synthesis of these derivatives was achieved using Wittig olefination, O-alkylation, and nucleophilic substitution reaction. The antimicrobial activity was performed by disc diffusion method utilizing Staphylococcus aureus as gram-positive and Escherichia coli as a gram-negative bacterial pathogen, respectively.

Synthesis and characterization of a new class of phenothiazine molecules with 10H-substituted morpholine & piperidine derivatives: A structural insight

A series of 10H-substituted phenothiazine-based molecules were prepared by the base-catalyzed reactions. The synthesized compounds are characterized by Mass spectroscopy, NMR, and SCXRD to examine the role of different functional groups involved in the intermolecular interactions and conformational geometries. The crystal packing of the compounds is governed by O–H⋯O, C–H⋯O, and π–π interactions. A complete understanding of the intermolecular interactions is studied employing the Hirshfeld analysis, 2D Fingerprint plot. Furthermore, the density functional theory (DFT/B3LYP) method at the 6–311++G(d,p) basis set was performed to support and compare experimental & theoretical geometrical parameters of phenothiazine derivatives.

Zirconium tetrachloride catalyzed one-pot highly efficient green synthesis of functionalized piperidines under visible light

Abstract Highly efficient multicomponent one-pot green synthesis of a series of pharmaceutically interesting functionalized piperidine derivatives has been developed based on a low-cost and eco-friendly zirconium tetrachloride catalyst via tandem reactions of 1,3-dicarbonyl compounds, aromatic aldehydes, and various amines in ethanol under visible light. High atom-economy, high yields, less reaction times, eco-friendly, and mild reaction conditions are some of the important features of this protocol. Key words: ZrCl 4 , piperidines, multi-component reactions, visible light

Discovery of Aryl Formyl Piperidine Derivatives as Potent, Reversible, and Selective Monoacylglycerol Lipase Inhibitors

Most of the current monoacylglycerol lipase (MAGL) inhibitors function by an irreversible mechanism of action, causing a series of side effects. Herein, starting from irreversible inhibitors, 25 compounds were synthesized and evaluated in vitro for MAGL inhibition, among which, compound 36 showed the most potent inhibitory activity (IC50 = 15 nM). Crucially, docking studies demonstrated that the m-chlorine-substituted aniline fragment occupied a hydrophobic subpocket enclosed by side chains of Val191, Tyr194, Val270, and Lys273, which creatively identify a new key anchoring point for the development of new MAGL inhibitors. Furthermore, in vivo evaluation innovatively revealed that this reversible inhibitor 36 significantly ameliorated depressive-like behaviors induced by reserpine. To the best of our knowledge, this is the first time that reversible inhibitors of MAGL were developed to support MAGL as a potential therapeutic target for depression.

Synthesis, In vitro and In silico Evaluation of a Series of Pyrazolines as New Anticholinesterase Agents

Background: Pyrazolines, electron-rich nitrogen carriers, are of great importance due to their potential applications for the treatment of many diseases including inflammation, infectious diseases and neurodegenerative disorders. Objectives: The purpose of this work was to synthesize new pyrazoline derivatives and evaluate their anticholinesterase effects. Methods: 1-Aryl-5-[4-(piperidin-1-yl)phenyl]-3-(3,4-dimethoxyphenyl)-4,5-dihydro-1H-pyrazoles (1-7) were synthesized via the treatment of 1-(3,4-dimethoxyphenyl)-3-[4-(piperidin-1-yl)phenyl]prop-2- en-1-one with arylhydrazine hydrochloride derivatives in acetic acid, whereas 1-aryl-5-[4- (morpholin-4-yl)phenyl]-3-(3,4-dimethoxyphenyl)-4,5-dihydro-1H-pyrazoles (8-14) were obtained by the treatment of 1-(3,4-dimethoxyphenyl)-3-[4-(morpholin-4-yl)phenyl]prop-2-en-1-one with arylhydrazine hydrochloride derivatives in acetic acid. Their inhibitory effects on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) were determined using a modification of Ellman’s spectrophotometric method. In silico docking and Absorption, Distribution, Metabolism and Excretion (ADME) studies were performed using Schrödinger’s Maestro molecular modeling package. Results: In general, piperidine derivatives were found to be more effective than morpholine derivatives on cholinesterases (ChEs). 1-Phenyl-5-[4-(piperidin-1-yl)phenyl]-3-(3,4-dimethoxyphenyl)- 4,5-dihydro-1H-pyrazole (1) and 1-(4-cyanophenyl)-5-[4-(piperidin-1-yl)phenyl]-3-(3,4- dimethoxyphenyl)-4,5-dihydro-1H-pyrazole (7) were identified as the most effective AChE inhibitors in this series with 40.92% and 38.98%, respectively. Compounds 1 and 7 were docked into the active site of human AChE (PDB code: 4EY7). Both the compounds were found to be capable of forming π-π stacking interactions with Trp286. Based on in silico ADME studies, these compounds are expected to have reasonable oral bioavailability. Conclusion: In the view of this work, the structural modification of the identified agents is going on for the generation of new anticholinesterase agents with enhanced efficacy.

Synthesis and Modeling Studies of Furoxan Coupled Spiro-Isoquinolino Piperidine Derivatives as NO Releasing PDE 5 Inhibitors.

Nitric oxide (NO) is considered to be one of the most important intracellular messengers that play an active role as neurotransmitter in regulation of various cardiovascular physiological and pathological processes. Nitric oxide (NO) is a major factor in penile erectile function. NO exerts a relaxing action on corpus cavernosum and penile arteries by activating smooth muscle soluble guanylate cyclase and increasing the intracellular concentration of cyclic guanosine monophosphate (cGMP). Phophodiesterase (PDE) inhibitors have potential therapeutic applications. NO hybridization has been found to improve and extend the pharmacological properties of the parental compound. The present study describes the synthesis of novel furoxan coupled spiro-isoquinolino-piperidine derivatives and their smooth muscle relaxant activity. The study reveals that, particularly 10d (1.50 ± 0.6) and 10g (1.65 ± 0.7) are moderate PDE 5 inhibitors as compared to Sidenafil (1.43 ± 0.5). The observed effect was explained by molecular modelling studies on phosphodiesterase.

Understanding the Conformational Behavior of Fluorinated Piperidines: The Origin of the Axial-F Preference.

Gaining an understanding of the conformational behavior of fluorinated compounds would allow for expansion of the current molecular design toolbox. In order to facilitate drug discovery efforts, a systematic survey of a series of diversely substituted and protected fluorinated piperidine derivatives has been carried out using NMR spectroscopy. Computational investigations reveal that, in addition to established delocalization forces such as charge–dipole interactions and hyperconjugation, solvation and solvent polarity play a major role. This work codifies a new design principle for conformationally rigid molecular scaffolds.

Design, Synthesis, Molecular Docking and Biological Activity of New Piperidine and Piperazine Derivatives of Dichloroacetate as Potential Anticancer Agents

Dichloroacetate (DCA) is a small anticancer agent acting through inhibition of pyruvate dehydrogenase kinases (PDKs) and preventing proliferation of tumor growth. In this study, a series of new piperidine and piperazine derivatives of DCA were designed and subjected to molecular docking analysis. Based on the docking results, nine compounds with a lowest binding energy and better interaction with PDK isoenzymes were selected and synthesized. The cytotoxic activities of the synthesized compounds were evaluated against HT-29 and MCF7 human cancer cell lines. These compounds showed moderate potency and much higher anticancer activity than DCA. The most active compound of the series (f1) showed IC50 value of 7.79 μM against HT-29 cell line.

Highly Diastereoselective Functionalization of Piperidines by Photoredox-Catalyzed α-Amino C-H Arylation and Epimerization.

We report a photoredox-catalyzed α-amino C-H arylation reaction of highly substituted piperidine derivatives with electron-deficient cyano(hetero)arenes. The scope and limitations of the reaction were explored, with piperidines bearing multiple substitution patterns providing the arylated products in good yields and with high diastereoselectivity. To probe the mechanism of the overall transformation, optical and fluorescent spectroscopic methods were used to investigate the reaction. By employing flash-quench transient absorption spectroscopy, we were able to observe electron transfer processes associated with radical formation beyond the initial excited-state Ir(ppy)3 oxidation. Following the rapid and unselective C-H arylation reaction, a slower epimerization occurs to provide the high diastereomer ratio observed for a majority of the products. Several stereoisomerically pure products were resubjected to the reaction conditions, each of which converged to the experimentally observed diastereomer ratios. The observed distribution of diastereomers corresponds to a thermodynamic ratio of isomers based upon their calculated relative energies using density functional theory (DFT).

Arylaminopropanone Derivatives as Potential Cholinesterase Inhibitors: Synthesis, Docking Study and Biological Evaluation

Neurodegenerative diseases in which the decrease of the acetylcholine is observed are growing worldwide. In the present study, a series of new arylaminopropanone derivatives with N-phenylcarbamate moiety (1–16) were prepared as potential acetylcholinesterase and butyrylcholinesterase inhibitors. In vitro enzyme assays were performed; the results are expressed as a percentage of inhibition and the IC50 values. The inhibitory activities were compared with reference drugs galantamine and rivastigmine showing piperidine derivatives (1–3) as the most potent. A possible mechanism of action for these compounds was determined from a molecular modelling study by using combined techniques of docking, molecular dynamics simulations and quantum mechanics calculations.

Bioinformatic study on Some Phenyl piperidine derivatives as novel serotonin transporter (SERT) inhibitors for antipsychotic agents targeting Depression

Bioinformatic study on Some Phenyl piperidine derivatives as novel serotonin transporter (SERT) inhibitors for antipsychotic agents targeting Depression

Switching Electrophile Intermediates to Nucleophiles: Michael and Oxa-Diels-Alder Reactions to Afford Polyoxy-Functionalized Piperidine Derivatives with Tetrasubstituted Carbon.

Michael, Michael-annulation, and oxa-Diels-Alder reactions of carbohydrate derivatives that afford polyoxy-functionalized piperidine derivatives bearing tetrasubstituted carbon at the 3-position of the piperidine ring are reported. Iminium ions generated from carbohydrate derivatives with amines were converted to enamines in situ, which acted as nucleophiles. As a result, substituents were introduced at the 3-position or both 2- and 3-positions of the piperidines bearing polyoxy groups. This strategy will be useful in drug discovery efforts.

Synthesis and pharmacological evaluation of 3-[5-(aryl-[1,3,4]oxadiazole-2-yl]-piperidine derivatives as anticonvulsant and antidepressant agents

In the present study, we have synthesized a series of fifteen nipecotic acid 1,3,4-oxadiazole based hybrids with significant (60–78%) yields. All the compounds were characterized by using different spectroanalytical techniques such as FT-IR, 1H NMR, 13C NMR, and elemental analysis. This design strategy was validated by using in vivo anti-epileptic and anti-depressant bioassay models. Anti-convulsant activity was evaluated using subcutaneous pentylenetetrazol (scPTZ) in mice and MES induced seizure. Among a spectrum of activities, three compounds (4i, 4m, and 4n) displayed significant activity against pentylenetetrazole (scPTZ) induced seizures. No disruptions in motor co-ordination were observed in mice pretreated with the test compounds in the rotarod test. Their influence on the safety profile of elevated serum levels of biochemical markers such as hepatic and renal toxicity has been found to be safe. The derivatives also show marked anti-depressant activity, devoid of serotonergic augmentation as assessed using the despair swim test, 5-hydroxytryptophan (5-HTP)-induced head twitch test and learned helplessness test. In silico docking studies targeted on homology modelled GABA transporter 1 (GAT1) protein shows the critical enzyme-ligand interactions leading to the inhibition of the GAT1 transporter. The compound 4m was found to be the most active compound among all the synthesized compounds.

Antifungal Activity of Morpholine and Piperidine Based Surfactants

Abstract Microorganisms have the remarkable capacity to develop resistance to antimicrobial agents. This is of particular concern for fungal pathogens which cause devastating invasive infections with limited treatment options. Thus the need for new antifungal agents is undeniable. This work presents the antifungal properties of four surfactant groups, namely two groups of sulfobetaines and two groups of quaternary ammonium compounds, all morpholine and piperidine derivatives, against drug susceptible or drug resistant Candida albicans and Cryptococcus neoformans. The values of minimum inhibitory and fungicidal concentrations were determined. As follows from the results, the activities of the obtained compounds differed, however the most active agents from each homologous series of compounds, such as P16S3, P16S4 and C16S3, were pointed out.

Functionalization of Piperidine Derivatives for the Site-Selective and Stereoselective Synthesis of Positional Analogues of Methylphenidate.

Rhodium‐catalyzed C−H insertions and cyclopropanations of donor/acceptor carbenes have been used for the synthesis of positional analogues of methylphenidate. The site selectivity is controlled by the catalyst and the amine protecting group. C−H functionalization of N‐Boc‐piperidine using Rh2(R‐TCPTAD)4, or N‐brosyl‐piperidine using Rh2(R‐TPPTTL)4 generated 2‐substitited analogues. In contrast, when N‐α‐oxoarylacetyl‐piperidines were used in combination with Rh2(S‐2‐Cl‐5‐BrTPCP)4, the C−H functionalization produced 4‐susbstiuted analogues. Finally, the 3‐substituted analogues were prepared indirectly by cyclopropanation of N‐Boc‐tetrahydropyridine followed by reductive regio‐ and stereoselective ring‐opening of the cyclopropanes.

Synthesis and Biological Activity of Triacetonamine

Sterically hindered amines such as triacetonamine and certain closely related analogs have been applied in medicine, pharmacology and industry. Various methods of synthesis of 2,2,6,6-tetramethylpiperidin-4-one (triacetonamine) derivatives start generally with acetone, phorone, piperidine N-oxides, piperidine alcohols, and 4-dimethylamine piperidine derivatives. Physical properties of triacetonamine including density, boiling point, flash point, and melting point have been determined. Reactions of triacetonamine derivatives with various organic reagents are also summarized. Triacetonamine derivatives react via three functional groups including carbonyl, methylenes adjacent to the carbonyl group, and NH. Some other miscellaneous reactions are presented. Conformation of triacetonamine is described. Theoretical models for the conformations of triacetonamine have been developed by quantum and molecular mechanics methods. Triacetonamine demonstrates different types of biological activities, such as antialzheimer, antifungal, antimicrobial, anti-HIV, anticancer, antioxidant, P38 kinase inhibitor, DNA labelling, antispasmodic, and psychotropic, and high ganglionic blocking.

Temperature‐Dependent Green Synthesis of New Series of Mannich Bases from 4‐Hydroxy‐pyridine‐2‐one and Their Antioxidant Activity Evaluation

AbstractA novel class of bio‐based 4‐hydroxy‐2‐pyridones was synthesized via Mannich reaction under solvent free conditions in absence any catalyst at room temperature. Interestingly, in thermal condition, the yields of these products were decreased and others products (from condensation of two molecules of 2‐pyridone and one molecule of aldehyde) were obtained. Then the antioxidant activity of the synthesized compounds were evaluated by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging assay methods. In general all of products showed significant radical scavenging potential, but the derivatives of pyrrolidine were more significant effective than the piperidine derivatives. This protocol provides a convenient, room temperature, solvent‐free, and catalyst‐free access to new 3‐substituted‐4‐hydroxy‐2‐pyridones.

Synthesis and Antimalarial Activity of 1,4-Disubstituted Piperidine Derivatives.

In order to prepare, at low cost, new compounds active against Plasmodium falciparum, and with a less side-effects, we have designed and synthesized a library of 1,4-disubstituted piperidine derivatives from 4-aminopiperidine derivatives 6. The resulting compound library has been evaluated against chloroquine-sensitive (3D7) and chloroquine-resistant (W2) strains of P. falciparum. The most active molecules—compounds 12d (13.64 nM (3D7)), 13b (4.19 nM (3D7) and 13.30 nM (W2)), and 12a (11.6 nM (W2))—were comparable to chloroquine (22.38 nM (3D7) and 134.12 nM (W2)).

Synthesis of β-Dicarbonylated Tetrahydropiperidines via Direct Oxidative Cross-Coupling between Different C(sp3)-H Bonds.

A novel and convenient synthesis of β-dicarbonylated tetrahydropiperidines from the cascade reactions of piperidine derivatives with methyl ketones is presented. Mechanistically, the formation of the title compounds involves a hitherto unreported oxidative cross-coupling between different C(sp3)-H bonds through the in situ generation of a cyclic enamine and an α-keto radical as the key intermediates followed by their radical addition and further oxidation of the addition adduct. To our knowledge, this is the first example in which β-dicarbonyl-substituted tetrahydropiperidines were prepared using readily available saturated cyclic amines as substrates and inexpensive and ubiquitous methyl ketones as dicarbonylation reagents. In addition, the product thus obtained could be easily transformed into structurally and pharmaceutically interesting polycyclic compounds in good efficiency.