Synthesis, Anti-Inflammatory Activity, and COX-1/2 Inhibition Profile of Some Novel Non-Acidic Polysubstituted Pyrazoles and Pyrano[2,3-c ]pyrazoles

Ligand-free palladium-catalyzed synthesis of 3-(2,2-dialkyl-2H-chromen-4-yl)-2-phenylimidazo[1,2-a]pyridine derivatives: molecular docking investigation of their potential as DNA gyrase inhibitors and evaluation of their antibacterial activities

Palladium-catalyzed reactions between imidazo[1,2-a]pyridine derivatives and 4-bromo-2,2-dialkyl-substituted 2H-chromenes under microwave irradiation at 100 W, 120 °C for 20-30 min provided a series of new 3-(2,2-dialkyl-2H-chromen-4-yl)-2-phenylimidazo[1,2-a]pyridine derivatives in good to excellent yields. The structures of the synthesized compounds were confirmed through spectroscopic techniques (NMR and HRMS). The X-ray single-crystal structure of compound 16e was also determined. Shorter reaction time, high yield and good substrate scope were the major advantages of this method. All these compounds were further investigated in vitro for the evaluation of their antibacterial potency using the agar well diffusion method against human pathogenic Gram-negative E. coli and Gram-positive S. aureus bacteria, with the determination of their minimum inhibitory concentration (MIC) values. Indeed, compound 16h strongly inhibited DNA gyrase in silico with a binding affinity of -8.7 kcal mol-1 and exhibited zone of inhibition (ZI) values of 19 mm and MIC values of 10 μg mL-1 in both Gram-negative E. coli and Gram-positive S. aureus, relative to the standard drug gentamicin. By analyzing the structure-activity relationships based on the molecular docking results and the potent antibacterial activities, it could be concluded that these new phenylimidazo[1,2-a]pyridine-chromene derivatives have the potential to be effective druggable antibacterial agents.

New Pyranopyrazole-Based Indolin-2,3-Dione Hybrid as Effective Inhibitors of Xanthine Oxidase: Synthesis, In Vitro, and Molecular Modeling Approaches

In the current study, new pyranopyrazole analogs (9a-d and 10a-d) were synthesized through a one-pot condensation reaction of 2-arylacetohydrazide. The inhibitory abilities were investigated against the xanthine oxidase (XO) enzyme through experimental and molecular docking analyses. The synthesis studies were based on ultrasound-mediated condensation reactions of four-component containing 2-arylacetohydrazide, ethyl acetoacetate, indoline-2,3-dione, and ethyl 2-cyanoacetate/malononitrile in various solvents and catalysts to yield pyranopyrazole analogs (9a-d and 10a-d) in a short reaction time and remarkably favorable yields ranging from 79% to 92%. On the basis of the XO inhibition study of compounds 9a-d and 10a-d, compound 10d was the most potent (IC50 = 0.09 ± 0.22 µM), followed by 9c (0.12 ± 0.11 µM). With IC50 values of 0.20 ± 0.27 and 0.17 ± 0.11 µM respectively, compounds 10a and 10c exhibited moderate activity. The other compounds have shown less activity compared to the allopurinol control (IC50 = 0.14 ± 0.10 µM). Furthermore, in the molecular docking analysis, compound 10d was predicted to have the highest binding affinity against the target XO enzyme.

Access Polyarylbipyrazoles via Palladium-Catalysis and Visible-Light-Driven C(sp3)-P(V) Cleavage Relay Strategy

An unprecedented palladium-catalyzed and visible-light-driven relay reaction of allenylphosphine oxide with in situ generated nitrile imines is presented for the direct synthesis of highly valuable polyarylbipyrazole skeletons. This one-pot strategy involves double 1,3-dipolar cycloaddition and C(sp3)-P(V) bond cleavage under photocatalyst-free and mild reaction conditions. The approach features simple operation, a high step economy, and a broad substrate scope, affording the corresponding products in moderate to excellent yields.

Design, synthesis and in silico insights of novel 1,2,3-triazole benzenesulfonamide derivatives as potential carbonic anhydrase IX and XII inhibitors with promising anticancer activity

Novel 1,2,3-triazole benzenesulfonamide derivatives were designed as inhibitors for the tumor- related hCA IX and XII isoforms. Most of the synthesized compounds showed good inhibitory activity against hCA IX and hCA XII isoforms. Compounds 4d, 5h and 6b, exhibited remarkable activity as hCA IX inhibitors, with Ki values in the range of 0.03 to 0.06 µM, more potent than AAZ. Additionally, compounds 5b and 6d, efficiently inhibited hCA XII isoform, with Ki value of 0.02 µM, respectively, similar to AAZ. Further investigation for those potent derivatives against MCF-7, Hep-3B and WI-38 cell lines was achieved. Compounds 4d and 6d exerted dual cytotoxic activity against MCF-7 and Hep-3B cell lines, with IC50 values of 3.35 & 2.12 µM against MCF-7 cell line and 1.72 & 1.56 µM against Hep-3B cell line, with high SI values ranged from 8.92 to 17.38 on both of the cell lines. Besides, they showed a high safety profile against normal human cell line, WI-38. Moreover, compound 5h had better cytotoxic effect on MCF-7 than the reference, DOX, with IC50 value of 4.02 µM. While, compounds 5b and 6b showed higher activity against Hep-3B if compared to the reference drug, 5-FU. From ADME study, compounds 4d, 5b, 6b and 6d obeyed Lipinski's rule of five, and they might be orally active derivatives, while, compound 5h exerted less oral bioavailability than the reference standard acetazolamide. Molecular docking and MDS studies predicted the binding mode and the stability of the target compounds inside hCA IX and hCA XII active sites, especially for compounds 5b and 6b.

Synthesis, anti-leukemia activity, and molecular docking of novel 3,16-androstenedione derivatives

In this study, we synthesized androsta-4,14-diene-3,16-dione, 12β-hydroxyandrosta-4,14-diene-3,16-dione, and other 3,16-androstenedione derivatives from commercially available dehydroepiandrosterone as a starting material in 9-13 steps with high yields. The bioactivity of the obtained compounds was evaluated. Compounds 14a and 23a were shown to have high antitumor activity against acute lymphoblastic leukemia cell lines Nalm-6 and BALL-1, respectively. Network pharmacology analysis showed that the anti-leukemia activity of compounds 14a and 23a might be related to the JAK2, ABL1 protein, and PI3K/Akt signaling pathways. The molecular docking of compounds 14a and 23a identified possible active sites, with the lowest docking scores for PTGS2 and MAPK14, respectively. In addition, the absorption, distribution, metabolism, and excretion prediction results revealed the drug-likeness of the two compounds. Therefore, compounds 14a and 23a should be considered anti-leukemia candidates in future studies.

Design and Development of COX-II Inhibitors: Current Scenario and Future Perspective

Innate inflammation beyond a threshold is a significant problem involved in cardiovascular diseases, cancer, and many other chronic conditions. Cyclooxygenase (COX) enzymes are key inflammatory markers as they catalyze prostaglandins production and are crucial for inflammation processes. While COX-I is constitutively expressed and is generally involved in "housekeeping" roles, the expression of the COX-II isoform is induced by the stimulation of different inflammatory cytokines and also promotes the further generation of pro-inflammatory cytokines and chemokines, which affect the prognosis of various diseases. Hence, COX-II is considered an important therapeutic target for drug development against inflammation-related illnesses. Several selective COX-II inhibitors with safe gastric safety profiles features that do not cause gastrointestinal complications associated with classic anti-inflammatory drugs have been developed. Nevertheless, there is mounting evidence of cardiovascular side effects from COX-II inhibitors that resulted in the withdrawal of market-approved anti-COX-II drugs. This necessitates the development of COX-II inhibitors that not only exhibit inhibit potency but also are free of side effects. Probing the scaffold diversity of known inhibitors is vital to achieving this goal. A systematic review and discussion on the scaffold diversity of COX inhibitors are still limited. To address this gap, herein we present an overview of chemical structures and inhibitory activity of different scaffolds of known COX-II inhibitors. The insights from this article could be helpful in seeding the development of next-generation COX-II inhibitors.

Vision on Synthetic and Medicinal Facets of 1,2,4-Triazolo[3,4-b][1,3,4]thiadiazine Scaffold

The present review article strives to compile the latest synthetic approaches for the synthesis of triazolothiadiazine and its derivatives, along with their diverse pharmacological activities, viz. anticancer, antimicrobial, analgesic and anti-inflammatory, antioxidant, antiviral, enzyme inhibitors (carbonic anhydrase inhibitors, cholinesterase inhibitors, alkaline phosphatase inhibitors, anti-lipase activity, and aromatase inhibitors) and antitubercular agents. The review focuses particularly on the structure–activity relationship of biologically important 1,2,4-triazolo[3,4-b][1,3,4]thiadiazines, which have profound importance in drug design, discovery and development. In silico pharmacokinetic and molecular modeling studies have also been summarized. It is hoped that this review article will be of help to researchers engaged in the development of new biologically active entities for the rational design and development of new target-oriented 1,2,4-triazolo[3,4-b][1,3,4]thiadiazine-based drugs for the treatment of multifunctional diseases.

Chemo- and regioselective defluorinative annulation of (trifluoromethyl)alkenes with pyrazolones: synthesis and insecticidal activity of 6-fluoro-1,4-dihydropyrano[2,3-c]pyrazoles

The chemo- and regioselective defluorinative [3 + 3] annulation of (trifluoromethyl)alkenes and pyrazolones gives useful 6-fluoro-1,4-dihydropyrano[2,3-c]pyrazoles.

Inhibitory activities of bipyrazoles: a patent review

Introduction: Bipyrazole is constituted from two pyrazole units either in their fully aromatic or partially hydrogenated forms. Pyrazoles are widely available in pharmaceutical and agrochemical products. Some pyrazoles are essential parts of commercial drugs in the market. This inspired us to collect the pharmacological activities of bipyrazoles that have potential therapeutic behaviors in several biological aspects but none of them were included in commercial drugs.Areas covered: This review covers all biological and pharmacological potentials of bipyrazole derivatives during 2010-2021. The topics of this review comprised anticancer, antioxidant, anti-inflammatory, antimicrobial, antitubercular, antimalarial, insecticidal activities as well as enzymatic inhibitions.Expert opinion: Bipyrazoles demonstrated a wide array of potent activities against various diseases such as anticancer, antitubercular, anti-inflammatory, and antimicrobial activities. Those are of great benefits for medicinal researchers to develop promising building blocks of bipyrazoles for treatment of diseases. The SAR studies showed that metallated bipyrazoles had better biological activities than bipyrazole ligands. For example, gold(III) and iridium(II) complexes of bipyrazoles were proved to be anticancer agents, and copper(I) as well as silver(I) complexes had excellent antibacterial activities. Several bipyrazoles were reported as antimalarial inhibitors better than chloroquine, the possible COVID-19 drug.

Synthesis, DFT calculation, pharmacological evaluation, and catalytic application in the synthesis of diverse pyrano[2,3-c]pyrazole derivatives

Pyranopyrazole and its derivatives are classified to be a pharmacologically significant active scaffold for almost all modes of biological activities. In this work, An efficient, green, and facile three-component reaction for preparing pyrano[2,3-c]pyrazole derivatives via the condensation reaction of 5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one, ethyl acetoacetate, and malononitrile in the presence of ZnO Nanoparticle. The products are produced with high yields and in shorter reaction times. It also is mild, safe, green, and environmentally friendly. The geometric parameters such as dipole moment, bond length, dihedral angles, total energy, heat of formation, atomic charges and energies at a highly accurate for prepared compounds were computed by Denisty Functional Theory along with the B3LYP functional. The newly synthesized compounds were screened for their anti-inflammatory and antioxidant activity. Some of the tested compounds displayed promising activities. The newly prepared compounds were found to be potent towards the antioxidant activity. Results indicated that compounds 11 and 12 exhibited significant (p ≥ 0.05) in vitro total antioxidant activity as 44.93 ± 0.15 and 39.60 ± 0.10 U/ML, respectively higher than standard ascorbic acid (29.40 ± 0.62).

Optimization of pyrazole-based compounds with 1,2,4-triazole-3-thiol moiety as selective COX-2 inhibitors cardioprotective drug candidates: Design, synthesis, cyclooxygenase inhibition, anti-inflammatory, ulcerogenicity, cardiovascular evaluation, and molecular modeling studies

The cardiovascular side effects associated with COX-2 selective drugs were the worst for coxibs leading to their withdrawal from the market a few years after their discovery. Therefore, the design of new series of pyrazole (4a,b 5a,b, 7a,b, 9a,b, 10a-h, and 11a-f) substituted with a triazole moiety as selective COX-2 inhibitors with cardioprotective effect was aimed in this paper. The target compounds were prepared and evaluated in-vitro against COX-1 and COX-2 enzymes. Compound 5-(5-Methyl-1-phenyl-1H-pyrazol-4-yl)-4H-1,2,4-triazole-3-thiol (7a) showed the highest selectivity towards COX-2 enzyme (S.I. = 27.56) and was the most active anti-inflammatory agent. Interestingly, its cardiovascular profile showed the cardiac biomarkers (ALP, AST, CK-MB, and LDH), as well as inflammatory cytokines named (TNF-α and IL-6) nearly similar to the control. Besides, a histopathological study of the heart muscle and the stomach was also included. The results confirmed that compound 7a has a more favorable cardio profile than celecoxib. Moreover, docking simulation for the most selective compounds 4b, 7a, 10e, 11c, and 11e inside COX-2 active site was performed to explain their binding mode. Finally, an ADME study was applied and proved the promising activity of the new compounds as a new oral anti-inflammatory agent. In conclusion, the newly developed compound 7a represents a potential selective COX-2 NSAID candidate with minimum cardiovascular risks.

Development of pyrazole derivatives in the management of inflammation

The therapeutic limitations and poor management of inflammatory conditions are anticipated to impact patients negatively over the coming decades. Following the synthesis of the first pyrazole-antipyrine in 1887, several other derivatives have been screened for anti-inflammatory, analgesic, and antipyretic activities. Arguably, the pyrazole ring, as a major pharmacophore and central scaffold partly, defines the pharmacological profile of several derivatives. In this review, we explore the structural-activity relationship that accounts for the pharmacological profile of pyrazole derivatives and highlights future research perspectives capable of optimizing current advancement in the search for safe and efficacy anti-inflammatory drugs. The flourishing research into the pyrazole derivatives as drug candidates has advanced our understanding of inflammation-related diseases and treatment.

New substituted pyrazole derivatives targeting COXs as potential safe anti-inflammatory agents

Aim: Everyday studies prove the increasing need for newer and safer agents to control cellular inflammatory response, an underlying cause for the pathophysiology of many other clinical cases. Results: Two newly designed sets of schiff 5a-h and chlacone 6a-f substituted pyrazoles were synthesized and evaluated for their in vivo/vitro anti-inflammatory activities. Most potent representatives were chosen for investigation of ulcerogenic and molecular docking properties. Conclusion: The synthesized compounds showed considerable edema inhibition percentage range if compared with celecoxib (13-93% and 58-93%, respectively) at different time intervals. Compound 6e showed the best screening results if compared with celecoxib (inhibition % = 93.62 and 93.51% at 5 h, COX-1/COX-2 selectivity index SI = 215.44 and 308.16 and ulcer index = 7.25 and 8, respectively).

A chemo- and regiocontrolled approach to bipyrazoles and pyridones via the reaction of ethyl 5-acyl-4-pyrone-2-carboxylates with hydrazines

Chemo- and regiocontrolled syntheses of pyrazoles and pyridones are presented on the basis of 4-pyrones. A novel approach towards highly functionalized 3,4'-bipyrazoles has been developed by using reactions of ethyl 5-acylcomanoates with hydrazines. The acid-promoted double cyclocondensation allows switching of the structure of the pyrazole rings easily through changing both the nature of hydrazine and the reaction conditions. The transformation of 4-pyrones with phenylhydrazine in EtOH at -20 °C leads to hydroxypyridones as monoaddition products which can be used as precursors for the preparation of pyridone and pyrazole derivatives. A novel rearrangement of 2-hydroxypyridone to pyrazolyl-1,3-diketones in DMSO was found. The structure and regiochemistry of bipyrazoles were confirmed by X-ray analysis and 2D NMR experiments.

Facile synthesis of new pyrazolo[4′,3′:5,6]pyrano[2,3-d]pyrimidin-5(1H)-ones via the tandem intramolecular Pinner–Dimroth rearrangement and their antibacterial evaluation

Some new 7-alkyl-4,6-dihydropyrazolo[4′,3′:5,6]pyrano[2,3-d]pyrimidin-5(1H)-ones were prepared through heterocyclization of 6-amino-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles with aliphatic carboxylic acids in the presence of phosphoryl chloride under reflux in high yields. The suggested mechanism involves a tandem intramolecular Pinner–Dimroth rearrangement. The products were characterized on the basis of FT-IR, 1H NMR, and 13C NMR spectral and microanalytical data and evaluated for their antibacterial activity against Gram-positive bacteria (Staphylococcus aureus and Staphylococcus epidermidis) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) using the disk diffusion method.

Synthesis, anti-inflammatory screening, molecular docking, and COX-1,2/-5-LOX inhibition profile of some novel quinoline derivatives

New quinoline compounds comprising pyrazole scaffold through different amide linkages were synthesized. The synthesized compounds were evaluated for their anti-inflammatory activity. Eight compounds (5c, 11b,c, 12c, 14a,b, 20a and 21a) were found to exhibit promising anti-inflammatory profiles in acute and sub-acute inflammatory models. They were screened for their ulcerogenic activity and none of them showed significant ulcerogenic activity comparable to the reference drug celecoxib and are well tolerated by experimental animals with high safety margin (ALD50 > 0.3 g/kg). Compounds 5c, 11b,c, 12c, 14a,b, 20a and 21a showed significant in vitro LOX inhibitory activity higher than that of zileuton. In vitro COX-1/COX-2 inhibition study revealed that compounds 12c, 14a,b and 20a showed higher selectivity towards COX-2 than COX-1. Among the tested compounds, 12c, 14a and 14b showed the highest inhibitory activity against COX-2 with an IC50 values of 0.1, 0.11 and 0.11 μM respectively. The docking experiments attempted to postulate the binding mode for the most active compounds in the binding site of COX-2 enzymes and confirmed the high selectivity binding towards COX-2 enzyme over COX-1.

An efficient and green approach for the synthesis of 2,4-dihydropyrano[2,3-c]pyrazole-3-carboxylates using Bi2O3/ZrO2 as a reusable catalyst

A novel material of bismuth loaded on zirconia (Bi2O3/ZrO2) is synthesized by simple wet-impregnation method and characterized by several techniques (P-XRD, TEM, SEM, BET, etc.). Bi2O3/ZrO2 proved to be a good catalyst for the four-component, one-pot reaction to produce a new series of 2,4-dihydropyrano[2,3-c]pyrazole-3-carboxylate derivatives with excellent yields (91 to 98%) under mild conditions at RT with short reaction times (≈20 min). The structures of the target molecules were confirmed by 1H NMR, 13C NMR, 15N NMR, HRMS and FT-IR. The catalyst is easily separable and can be reused for six cycles without ostensible loss of activity. This method is inexpensive, atom-efficient and no chromatographic separations are needed.

Synthesis, characterization and in vitro antitrypanosomal activities of new carboxamides bearing quinoline moiety

The reported toxicities of current antitrypanosomal drugs and the emergence of drug resistant trypanosomes underscore the need for the development of new antitrypanosomal agents. We report herein the synthesis and antitrypanosomal activity of 24 new amide derivatives of 3-aminoquinoline, bearing substituted benzenesulphonamide. Nine of the new derivatives showed comparable antitrypanosomal activities at IC50 range of 1-6 nM (melarsoprol 5 nM). Compound 11n and 11v are more promising antitrypanosomal agents with IC50 1.0 nM than the rest of the reported derivatives. The novel compounds showed satisfactory predicted physico-chemical properties including oral bioavailability, permeability and transport properties.