Pyrazole-based Compounds Research Articles

In Silico ADME And Molecular Docking Studies of New Thiazolyl-bipyrazole, Pyrazolopyridine and Pyrano[2,3-d]pyrazolopyridine Derivatives as Antibacterial Agents

: In this study, a series of novel pyrazole-based compounds were synthesized starting from the precursor ethyl 3-(4-amino-1-phenyl-3-((4-sulfamoylphenyl)carbamoyl)-1Hpyrazol- 5-yl)-3-oxopropanoate (2). Various synthetic routes were used to obtain pyrazolylpyrazolone 3, tricyclic dipyrazolopyridine 4a-c, thiazolyl-bipyrazoles 5 & 6, pyrazolo[4,3- b]pyridines 7 & 9, and tricyclic pyranopyrazolopyridine 10a–c. These compounds were screened for their antibacterial activity against four bacterial strains. The promising candidates 4a, 4b, 4c, 7, 9, and 10c exhibited minimum inhibitory concentrations ranging from 0.98 to 31.25 μg/mL. The in silico ADME properties for the active compounds exhibited similar physiochemical properties, with compound 9 demonstrating the best likeness and no inhibition effect on the popular drug metabolism enzyme CYP. Molecular docking simulations highlighted compounds 9 and 10c as potent antibacterial agents via DNA-gyrase inhibition

Design, synthesis and biological evaluation of novel pyrazole-based compounds as potential chemotherapeutic agents.

Aim: Design and synthesis of pyrazole-based chemotherapeutic agents. Materials & methods: A series of novel diphenyl pyrazole-chalcone derivatives were synthesized and assessed for their cytotoxic activities against 14 cancer cell lines and their antimicrobial activities against MRSA and Escherichia coli along with their safety using HSF normal cell line. Results & conclusion: Majority of the compounds showed moderate-to-significant anticancer activity with selective high percentage inhibition (>80%) against HNO-97 while being nontoxic toward normal cells. Compounds 6b and 6d were the most potent congeners with IC50 of 10 and 10.56μM respectively. The synthesized compounds exhibited moderate to potent antimicrobial activities. Interestingly, compound 6d exhibited a minimum inhibitory concentrationof 15.7μg/ml against MRSA; and a minimum inhibitory concentrationof 7.8μg/ml versus E. coli.

Unraveling the unexpected aggregation behavior of Pyrazole-Based compounds Targeting Mycobacterium tuberculosis UDP-Galactopyranose mutase

A pyrazole-based compound, MS208, was previously identified as an inhibitor of UDP-Galactopyranose Mutase from Mycobacterium tuberculosis (MtUGM). Targeting this enzyme is a novel therapeutic strategy for the development of new antituberculosis agents because MtUGM is an essential enzyme for the bacterial cell wall synthesis and it is not present in human. It was proposed that MS208 targets an allosteric site in MtUGM as MS208 followed a mixed inhibition model. DA10, an MS208 analogue, showed competitive inhibition rather than mixed inhibition. In this paper, we have used an integrated biophysical approach, including thermal shift assays, dynamic light scattering and nuclear magnetic resonance experiments, to show that MS208 and many analogues displayed unexpected aggregation behavior against MtUGM.

Exploring the Pharmacological Potential of Pyrazole Derivatives: A Comprehensive Review of Diverse Biological Activities

The different biological actions connected to pyrazole molecules are summarised in this review. The review emphasizes their potential as antimicrobial [1], anti-TMV analgesic [2], ACE inhibitor [3], anti-amoebic [5], and neuroprotective medicines [6]. The ability of pyrazole derivatives to modify particular enzymes, receptors, and pathways involved in a variety of illnesses and physiological processes has been thoroughly researched. Because of their adaptability in interacting with a variety of biological targets, pyrazole-based compounds are intriguing candidates for the creation of innovative medicines and agrochemicals. The synthesis and characterization of pyrazole derivatives are still being studied, and this work has the potential to lead to the development of novel therapeutics with applications in a variety of medical specialties. Key Words: Pyrazole, Biological Activity.

Amino-Pyrazoles in Medicinal Chemistry: A Review.

A pyrazole nucleus is an easy-to-prepare scaffold with large therapeutic potential. Consequently, the search for new pyrazole-based compounds is of great interest to the academic community as well as industry. In the last ten years, a large number of papers and reviews on the design, synthesis, and biological evaluation of different classes of pyrazoles and many pyrazole-containing compounds have been published. However, an overview of pyrazole derivatives bearing a free amino group at the 3, 4, or 5 position (namely, 3-aminopyrazoles, 4-aminopyrazoles, and 5-aminopyrazoles, respectively) and their biological properties is still missing, despite the fact that aminopyrazoles are advantageous frameworks able to provide useful ligands for receptors or enzymes, such as p38MAPK, and different kinases, COX and others, as well as targets important for bacterial and virus infections. With the aim to fill this gap, the present review focuses on aminopyrazole-based compounds studied as active agents in different therapeutic areas, with particular attention on the design and structure-activity relationships defined by each class of compounds. In particular, the most relevant results have been obtained for anticancer/anti-inflammatory compounds, as the recent approval of Pirtobrutinib demonstrates. The data reported here are collected from different databases (Scifinder, Web of Science, Scopus, Google Scholar, and Pubmed) using "aminopyrazole" as the keyword.

Synthesis, Density Functional Theory, Insecticidal Activity, and Molecular Docking of Some N-Heterocycles Derived from 2-((1,3-Diphenyl-1H-Pyrazol-4-yl)Methylene)Malonyl Diisothiocyanate

The extensive pharmacological applications of the pyrazole-based compounds stimulated us to synthesize the highly functionalized, pyrazolylmalonyl diisothiocyanate derivative (2) via treating 2-((1,3-diphenyl-1H-pyrazol-4-yl)methylene)malonyl dichloride (1) with ammonium thiocyanate in acetonitrile at room temperature. The diisothiocyanate derivative 2 was subsequently conducted with a double molar ratio of different nitrogen nucleophiles like 4-acetylaniline, 2-aminobenzoic acid, 6-aminothiouracil, 2-aminothiadiazole derivative, hydrazine, phenylhydrazine, thiophene-2-carbohydrazide, 2-hydroxybenzohydrazide, 2-cyanoacetohydrazide, thiourea, thiosemicarbazide, 2-aminoaniline, and thiocarbohydrazide, aiming to construct some valuable heterocyclic systems. The synthesized compounds were screened for their insecticidal activity against healthy late third instar larvae P. interpunctella and Nilaparvata lugens and the results showed that pyrimidinethione, thiadiazolotriazine, and tetrazinethione derivatives exhibited the highest insecticidal potency that are supported by DFT stimulation and their molecular docking.

New N-Alkylated Heterocyclic Compounds as Prospective NDM1 Inhibitors: Investigation of In Vitro and In Silico Properties.

A new family of pyrazole-based compounds (1–15) was synthesized and characterized using different physicochemical analyses, such as FTIR, UV-Visible, 1H, 13C NMR, and ESI/LC-MS. The compounds were evaluated for their in vitro antifungal and antibacterial activities against several fungal and bacterial strains. The results indicate that some compounds showed excellent antibacterial activity against E. coli, S. aureus, C. freundii, and L. monocytogenes strains. In contrast, none of the compounds had antifungal activity. Molecular electrostatic potential (MEP) map analyses and inductive and mesomeric effect studies were performed to study the relationship between the chemical structure of our compounds and the biological activity. In addition, molecular docking and virtual screening studies were carried out to rationalize the antibacterial findings to characterize the modes of binding of the most active compounds to the active pockets of NDM1 proteins.

Identification of a Unique Cytotoxic Thieno[2,3-c]Pyrazole Derivative with Potent and Selective Anticancer Effects In Vitro.

Simple SummaryDespite their documented antitumor effects, thienopyrazole-based compounds remain an underexplored class of molecules. In this study, a screening of 2000 novel molecules revealed a unique thienopyrazole derivative, Tpz-1, that elicited potent and selective programmed cell death in human blood, breast, colon, and cervical cancer cell lines when compared to non-cancerous human fibroblast (Hs27) cells. Furthermore, in HL-60 leukemia cells, Tpz-1 interfered with components of signaling pathways and the cytoskeleton that are important to cell shape, internal organization, growth, and division. These findings encourage the continued investigation and development of Tpz-1 and other thienopyrazole derivatives to target and treat cancers.In recent years, the thienopyrazole moiety has emerged as a pharmacologically active scaffold with antitumoral and kinase inhibitory activity. In this study, high-throughput screening of 2000 small molecules obtained from the ChemBridge DIVERset library revealed a unique thieno[2,3-c]pyrazole derivative (Tpz-1) with potent and selective cytotoxic effects on cancer cells. Compound Tpz-1 consistently induced cell death at low micromolar concentrations (0.19 μM to 2.99 μM) against a panel of 17 human cancer cell lines after 24 h, 48 h, or 72 h of exposure. Furthermore, an in vitro investigation of Tpz-1’s mechanism of action revealed that Tpz-1 interfered with cell cycle progression, reduced phosphorylation of p38, CREB, Akt, and STAT3 kinases, induced hyperphosphorylation of Fgr, Hck, and ERK 1/2 kinases, and disrupted microtubules and mitotic spindle formation. These findings support the continued exploration of Tpz-1 and other thieno[2,3-c]pyrazole-based compounds as potential small-molecule anticancer agents.

Design and Development of Ruthenium-Based Catalysts for Enabling Hydrogen Storage

For past decades, hydrocarbon-based fuels have been the primary source of energy as a necessity for modern machines and automotive vehicles. Despite use in combustion engines and power plants, fossil fuels reserves are unpredictable and the associated CO2 emissions are now causing terrible effects on the environment and human health. Researchers have realized H2 as a potentially safe and efficient energy source, with an energy density of 33.3 kWh per kg. Moreover, H2 is significantly more environmentally friendly as H2O is the only by-product. Currently, the development of on-board storage technology is progress for use in the transportation industry. The chemical storage of hydrogen, in which H2 is bound to a carrier molecule, provides a more practical and safer method to store and release immense amounts of H2. Ammonia Borane (H3N-BH3, AB) is a useful material for storing up to 19.6 wt% of and 0.145kg L-1 of H2 with the ability to release H2 under mild ambient conditions through exposure to a suitable catalyst. This project investigates the use of pyrazole-based compounds as ligands for η6-arene Ru-complexes in order to formulate efficient catalysts for AB dehydrogenation. Pyrazoles are interesting diaza-five member heterocycles and have strong electron-donating properties. Mono- and di-coordinating substituted pyrazole complexes and an unusual Cl-bridging dimeric Ru complex were successfully synthesized and characterized (NMR, ESI-MS and X-ray diffraction crystallography) before undergoing evaluation for AB dehydrogenation studies in a high-pressure stainless steel reactor. The dimeric Ru Cl-bridging catalyst released the largest H2 equivalent per mol of AB with 1.45 with a total of 7.82 bar of H2 pressure, proving to be the most successful catalyst in the series. However, from the H2 release profiles, it appears that catalysts undergo slow transformation where it is possible that the pyrazole ligands are lost. Further mechanistic studies are required to determine the decomposition process.

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.

New pyrimidine and pyrazole-based compounds as potential EGFR inhibitors: Synthesis, anticancer, antimicrobial evaluation and computational studies

This study was focused on the synthesis of new pyrimidines 4a,b, 5a,b and pyrazoles 6a, b as ATP mimicking tyrosine kinase inhibitors of the epidermal growth factor receptor (EGFR). The new compounds were assessed as cytotoxic candidates against human breast cancer cells (MCF-7) and hepatocellular carcinoma cells (HepG-2). All the new compounds appeared as more potent cytotoxic agents than erlotinib, while only compound 4a exhibited more potency than 5-flourouracil and 4b analogue was equipotent to it. Accordingly, the kinase suppression effect of 4a and 4b was further evaluated against EGFRWT, EGFRL858R and EGFRT790M. Both pyrimidine analogues 4a and 4b displayed outstanding inhibitory activity against EGFRWT and its two mutated isoforms EGFRL858R and EGFRT790M in comparing to erlotinib and osimertinib as reference drugs. Additionally, all the new analogues were subjected to antimicrobial assay. Interestingly, both 4a and 4b represented the most promising activity of wide spectrum antimicrobial effect against the examined microbes in comparison to gentamycin and ketoconazole as standard drugs. Moreover, docking results proved the good binding interactions of the compounds 4a and 4b with EGFRWT and EGFRT790M which were in accordance with the results of the in vitro enzyme assay. Additional in silico ADMET studies were performed for the new derivatives which represented their good oral absorption, good drug-likeness properties and low toxicity risks in human.

Energetic Tricyclic Polynitropyrazole and Its Salts: Proton-Locking Effect of Guanidium Cations.

An axisymmetric polynitro-pyrazole molecule, 3,5-di(3,5-dinitropyrazol-4-yl)]-4-nitro-1H-pyrazole (5), and its salts (6-12) were prepared and fully characterized. These compounds not only show promising energetic properties but also show a unique tautomeric switch via combining different cations with the axisymmetric compound (5). Its salts (6-9) remain axisymmetric when the cations are potassium, ammonium, or amino-1,2,4-triazolium. However, when the cations are guanidiums, the salts (10-12) dramatically become asymmetric owing to the fixed proton. The introduction of guanidium cations breaks the tautomeric equilibrium by blocking the prototropic transformations and results in the switch-off effect to tautomerism. The structural constraints of 1H NMR and 13C NMR spectra provide strong evidence for the unusual structural constraint phenomenon. These stabilized asymmetric tautomers are very important from the point of molecular recognition, and this research may promote further developments in synthetic and isolation methodologies for novel bioactive pyrazole-based compounds.

Tricyclic Pyrazole-Based Compounds as Useful Scaffolds for Cannabinoid CB1/CB2 Receptor Interaction.

Cannabinoids comprise different classes of compounds, which aroused interest in recent years because of their several pharmacological properties. Such properties include analgesic activity, bodyweight reduction, the antiemetic effect, the reduction of intraocular pressure and many others, which appear correlated to the affinity of cannabinoids towards CB1 and/or CB2 receptors. Within the search aiming to identify novel chemical scaffolds for cannabinoid receptor interaction, the CB1 antagonist/inverse agonist pyrazole-based derivative rimonabant has been modified, giving rise to several tricyclic pyrazole-based compounds, most of which endowed of high affinity and selectivity for CB1 or CB2 receptors. The aim of this review is to present the synthesis and summarize the SAR study of such tricyclic pyrazole-based compounds, evidencing, for some derivatives, their potential in the treatment of neuropathic pain, obesity or in the management of glaucoma.

Pyrazole-based compounds in chitosan liposomal emulsion for antimicrobial cotton fabrics

The chemistry of pyrazoles has gained increasing attention due to its diverse pharmacological properties such as antiviral, antagonist, antimicrobial, anticancer, anti-inflammatory, analgesic, anti-prostate cancer, herbicidal, acaricidal and insecticidal activities. 1-Phenyl pyrazole-3, 5-diamine, 4-[2-(4-methylphenyl) diazenyl] and 1H- pyrazole-3 (1), 5-diamine, 4-[2-(4-methylphenyl) diazenyl] (2) were synthesized, characterized and encapsulated into liposomal chitosan emulsions for textile finishing. The chemical modifications of cotton fabrics were demonstrated by infrared analysis. Retention of the fabric mechanical properties was investigated by reporting the tensile strength values. Synthesized pyrazole-based compounds were screened for cytotoxicity against skin fibroblast cell line and showed very limited toxicity for both compounds. Antimicrobial potentials of the treated cotton fabrics were tested against bacterial strains E. coli ATCC 8379 and Staphylococcus aureus ATCC 25923.

Structure of bis(nitrato)tetrakis(pyrazole)cobalt(II): Fine tuning in the stabilization of coordination entities by using intramolecular hydrogen bonding

The crystal and molecular structure of the title compound is presented and discussed in detail, and compared with some related pyrazole compounds. Focus is given on the often overlooked intramolecular hydrogen-bond stabilization that determines the structural conformation and also explains some unusual spectral properties. Ligand-field, EPR and infrared spectra are presented to illustrate the case on the title compound and also on a few related Cu(II) and Co(II) pyrazole-based compounds, compared with earlier reported Zn and Ni compounds. The observed N–H⋯O H-bond contacts correlate with the observed N–H stretching vibrations.

Perspective: the potential of pyrazole-based compounds in medicine

Pyrazoles are widely used as core motifs for a large number of compounds for various applications such as catalysis, agro-chemicals, building blocks of other compounds and in medicine. The attractiveness of pyrazole and its derivatives is their versatility that allows for synthesis of a series of analogues with different moieties in them, thus affecting the electronics and by extension the properties of the resultant compounds. In medicine pyrazole is found as a pharmacophore in some of the active biological molecules. While pyrazole derivatives have been extensively studied for many applications including anticancer, antimicrobial, anti-inflammatory, antiglycemic, anti-allergy and antiviral, much less has been reported on their metal counterparts in spite of the fact that metals have been shown to impart activity to ligands. Thus this perspective is intended to demonstrate the potential of pyrazole and pyrazolyl metal complexes in the areas of drug discovery and development. Several examples, that include palladium, platinum, copper, gold, zinc, cobalt, nickel, iron, copper, silver and gallium complexes, are used to bolster the above point. For the purposes of this review three areas are discussed, that is pyrazole metal complexes as: (i) anticancer, (ii) antibacterial/parasitic and (iii) antiviral agents.

In Vivo Trypanosomicidal Activity of Imidazole- or Pyrazole-Based Benzo[g]phthalazine Derivatives against Acute and Chronic Phases of Chagas Disease

The in vivo trypanosomicidal activity of the imidazole-based benzo[g]phthalazine derivatives 1-4 and of the new related pyrazole-based compounds 5 and 6 has been studied in both the acute and chronic phases of Chagas disease. As a rule, compounds 1-6 were more active and less toxic than benznidazole in the two stages of the disease, and the monosubstituted derivatives 2, 4, and 6 were more effective than their disubstituted analogs. Feasible mechanisms of action of compounds 1-6 against the parasite have been explored by considering their inhibitory effect on the Fe-SOD enzyme, the nature of the excreted metabolites and the ultrastructural alterations produced. A complementary histopathological analysis has confirmed that the monosubstituted derivatives are less toxic than the reference drug, with the behavior of the imidazole-based compound 4 being especially noteworthy.

Rational Design, Synthesis, and Potency of N‐Substituted Indoles, Pyrroles, and Triarylpyrazoles as Potential Fructose 1,6‐Bisphosphatase Inhibitors

By using computer modeling and lead structures from our earlier SAR results, a broad variety of pyrrole-, indole-, and pyrazole-based compounds were evaluated as potential fructose 1,6-bisphosphatase (FBPase) inhibitors. The docking studies yielded promising structures, and several were selected for synthesis and FBPase inhibition assays: 1-[4-(trifluoromethyl)benzoyl]-1H-indole-5-carboxamide, 1-(alpha-naphthalen-1-ylsulfonyl)-7-nitro-1H-indole, 5-(4-carboxyphenyl)-3-phenyl-1-[3-(trifluoromethyl)phenyl]-1H-pyrazole, 1-(4-carboxyphenylsulfonyl)-1H-pyrrole, and 1-(4-carbomethoxyphenylsulfonyl)-1H-pyrrole were synthesized and tested for inhibition of FBPase. The IC(50) values were determined to be 0.991 and 1.34 microM, and 575, 135, and 32 nM, respectively. The tested compounds were significantly more potent than the natural inhibitor AMP (4.0 microM) by an order of magnitude; indeed, the best inhibitor showed an IC(50) value toward FBPase more than two orders of magnitude better than that of AMP. This level of activity is virtually the same as that of the best currently known FBPase inhibitors. This work shows that such indole derivatives are promising candidates for drug development in the treatment of type II diabetes.

Discovery of Novel Transcription Factor Inhibitors Using a Pyrazole-based Small Molecule Library

A focused library of pyrazole-based compounds was constructed towards novel transcription factor inhibitors. Complementary hydrogen bonding interaction with b-sheet peptide structures was the basis for the design of 5-amino-3-pyrazole carboxamide scaffold. From the preliminary inhibition assay against several transcription factors, compounds 7e and 8g were identified as novel lead compounds against HIF-1a and NF-AT transcription factors, respectively.

Helicobacter pylori-selective Antibacterials Based on Inhibition of Pyrimidine Biosynthesis

We report the discovery of a class of pyrazole-based compounds that are potent inhibitors of the dihydroorotate dehydrogenase of Helicobacter pylori but that do not inhibit the cognate enzymes from Gram-positive bacteria or humans. In culture these compounds inhibit the growth of H. pylori selectively, showing no effect on other Gram-negative or Gram-positive bacteria or human cell lines. These compounds represent the first examples of H. pylori-specific antibacterial agents. Cellular activity within this structural class appears to be due to dihydroorotate dehydrogenase inhibition. Minor structural changes that abrogate in vitro inhibition of the enzyme likewise eliminate cellular activity. Furthermore, the minimum inhibitory concentrations of these compounds increase upon addition of orotate to the culture medium in a concentration-dependent manner, consistent with dihydroorotate dehydrogenase inhibition as the mechanism of cellular inhibition. The data presented here suggest that targeted inhibition of de novo pyrimidine biosynthesis may be a valuable mechanism for the development of antimicrobial agents selective for H. pylori.