Synthesis and antiviral activity of new pyrazole and thiazole derivatives

Synthesis of new selective agents with dual anti-inflammatory and SARS-CoV-2 Mpro inhibitory activity: Antipyrine-celecoxib hybrid analogues; COX-2, COVID-19 cytokine storm and replication inhibitory activities

Herein, a great aim to introduce novel pyrazolone derivatives with multiple activities, including selective COX-2 and cytokine inhibition in addition to SARS-CoV-2 Mpro inhibitory effects. All the synthesized compounds 4a-c, 5, 6a,b, 7a-f, 8a,b, 9a,b, 10a,b and 11a-f were evaluated in vitro for investigation of selective COX-2 inhibitory activity. The results introduced the most selective compounds 7a, 7d, 7e, 9a, and 11f that were further screened in vivo to evaluate their anti-inflammatory activity, safety concerning gastric ulcer and myocardial infarction. Compounds 7e, 9a and 11f exhibited % edema inhibition (43.87-54.31) compared to celecoxib (54.17%17 %) at the same time. Histopathological examination of gastric and cardiac tissues proved the safe profiles of compounds 7e and 11 f. The reduction in cardiac biomarkers level (CK-MP, AST, LDH) and the pro-inflammatory cytokines (TNF-α, IL-6 and IL-1β) ensured the cardiac safety of 7e and 11f. Also, RT-PCR results confirmed the efficacy of compounds 7e and 11f to inhibit gene expression of cytokines responsible for the overwhelming inflammation in COVID-19 infection, including TNF-α, IL-6, IL-2 and IL-1β. Additionally, SARS-CoV-2 Mpro inhibitory assay revealed the potency of the compound 7e against Mpro enzyme (IC50 = 13.24 μM). Furthermore, the proper fitting of 7e inside both COX-2 and Mpro active site through the docking study supported the affinity of 7e to inhibit both enzymes. Therefore, a belief stated that compound 7e is a promising lead compound with a safe profile, acting as a selective COX-2 and cytokine inhibitor. Also, 7e reduces the COVID-19 infection's cytokine storm and inhibits viral replication via targeting the Mpro enzyme.

Evaluation of the Antifungal Properties of Azomethine-Pyrazole Derivatives from a Structural Perspective

About 95 % of candidiasis infections worldwide are attributed to five Candida fungi species, with C. albicans being the most prevalent and severe. Due to resistance phenomena, the last decade has seen a significant challenge for candidiasis treatment with antifungal drugs, which has led to an urgent need for new antifungal agents. In this article, we report the synthesis of a series of azomethine-pyrazole derivatives bearing a para-substituted azo-phenyl ring. These compounds were evaluated as antifungal agents against Candida species and Cryptococcus neoformans strains. Compound ClAzoNH, substituted by chloride, displayed the highest toxicity on Candida albicans, with an MIC50 value of 2.08 μg/mL, while methoxy-substituted MeOAzoNH showed moderate inhibitory activity. The unsubstituted AzoNH compound exhibited the highest activity towards Candida tropicalis, Candida glabrata, Candida parapsilosis, and Candida krusei strains. In the case of C. albicans, the CaCYP51 protein appears to be the most probable biological target, while for C. neoformans, interactions with the CnFTase protein explained the in vitro results.

Synthesis, antibacterial activity, in silico ADMET prediction, docking, and molecular dynamics studies of substituted phenyl and furan ring containing thiazole Schiff base derivatives

This study synthesized eighteen phenyl and furan rings containing thiazole Schiff base derivatives 2(a-r) in five series, and spectral analyses confirmed their structures. The in vitro antibacterial activities of the synthesized analogs against two gram-positive and two gram-negative bacteria were evaluated by disk diffusion technique. Compounds (2d) and (2n) produced prominently high zone of inhibition with 48.3 ±  0.6 mm and 45.3 ±  0.6 mm against B. subtilis, respectively, compared to standard ceftriaxone (20.0 ±  1.0 mm). However, the antibacterial potency of the compounds with furan ring was more notable than that of phenyl ring-containing derivatives. Molecular docking and dynamic study were performed based on the wet lab outcomes of (2d) and (2n), where both derivatives remained in the binding site of the receptors during the whole simulation time with RMSD and RMSF values below 2 nm. In silico ADMET prediction studies of the synthesized compounds validated their oral bioavailability. A more detailed study of the quantitative structure-activity relationship is required to predict structural modification on bioactivity and MD simulation to understand their therapeutic potential and pharmacokinetics.

Synthesis of New Thiazole-Pyrazole Analogues: Molecular Modelling, Antiproliferative/Antiviral Activities, and ADME Studies

Twelve thiazole-pyrazole analogues 4, 6, and 8 were synthesized by introducing various pyrazole systems into the core, 2-((4-acetylphenyl)amino)-4-methylthiazole (2), through many synthetic approaches. The density functional theory (DFT) study of the synthesized analogues revealed coincided configurations of their highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO), except for the nitro derivatives, in which the intramolecular charge-transfer (CT) may be denoted as π → π* and n → π*. In addition, the in vitro antiproliferative efficacy towards some cancer cell lines was examined (Panc-1, HT-29, MCF-7) and the non-cancerous (WI-38), using Dasatinib (Reference). The analogues 4c and 4d demonstrated the most potent anticancer effect, particularly against Panc-1 and MCF-7 cells. Moreover, the antiviral activity against H5N1, using a plaque reduction assay, showed that analogue 6a exhibited the most potent antiviral activity (100% inhibition and TC50 = 61 μg/μL), comparable to the reference drug amantadine (TC50 = 72 μg/μL, 100% inhibition). Furthermore, the molecular docking disclosed that the analogues exhibited a range of interactions, such as H-bonding and π-π stacking, with binding affinities between -4.8558 and - 8.3673 kcal/mol. Additionally, the SwissADME predictions indicated that the synthesized analogues possess promising drug-like characteristics, but analogues 4a-d and 8c demonstrated inadequate solubility and bioavailability, which restricts their use as viable oral medications.

Environmentally Friendly Synthesis of New Mono- and Bis-Pyrazole Derivatives; In Vitro Antimicrobial, Antifungal, and Antioxidant Activity; and In Silico Studies: DFT, ADMETox, and Molecular Docking

Background/Objectives: Antimicrobial resistance and oxidative stress are major global health challenges, necessitating the development of novel therapeutic agents. Pyrazole derivatives, known for their diverse pharmacological properties, hold promise in addressing these issues. This study aimed to synthesize new mono- and bis-pyrazole derivatives using an eco-friendly, catalyst-free approach and evaluate their antioxidant, antibacterial, and antifungal activities, supported by in silico ADMET profiling, molecular docking, and Density Functional Theory (DFT) analysis. Methods: The compounds were synthesized via a green condensation reaction and characterized using NMR and mass spectrometry, which was verified by DFT analysis. Biological activities were assessed through DPPH and FRAP antioxidant assays, as well as disk diffusion and MIC methods, against bacterial strains (Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli) and fungal strains (Candida albicans and Aspergillus niger). Computational ADMET profiling evaluated pharmacokinetics and toxicity, while molecular docking assessed interactions with target proteins, including catalase, topoisomerase IV, and CYP51. Results: Theoretical calculations using DFT were in agreement with the experimental results; regarding biological activities, O4 demonstrated the most significant antioxidant activity, with 80.14% DPPH radical scavenging and an IC50 value of 40.91 µg/mL. It exhibited potent antimicrobial activity, surpassing Streptomycin with a 30 mm inhibition zone against Pseudomonas aeruginosa and showing strong efficacy against Staphylococcus aureus and Candida albicans. Computational studies confirmed favorable pharmacokinetic properties, no AMES toxicity, and strong binding affinities. DFT analysis revealed O4's stability and reactivity, further validating its potential as a therapeutic candidate. Conclusions: This study identified and characterized novel pyrazole derivatives with promising biological and pharmacological properties. O4 emerged as the most potent compound, demonstrating strong antioxidant and antimicrobial activities alongside favorable computational profiles. These findings highlight the potential of the synthetized compounds for therapeutic development and underscore the value of integrating green synthesis with computational techniques in drug discovery.

Comprehensive Insight into Green Synthesis Approaches, Structural Activity Relationship, and Therapeutic Potential of Pyrazolic Chalcone Derivative

Pyrazolic chalcone exhibits diverse therapeutic activities, including anti-inflammatory, antioxidant, antimicrobial, antitumor, and anti-diabetic properties. Structural activity relationship (SAR) studies play a crucial role in understanding the molecular aspects governing their biological effects, guiding the rational design of derivatives with enhanced efficacy and reduced side effects. This review provides an overview of pyrazolic chalcone derivatives, emphasizing their synthesis through both conventional and green methods. In comparison, conventional synthesis methods have been widely employed in the past for the production of pyrazolic chalcones, often relying on traditional chemical processes that may involve the use of hazardous reagents and generate significant waste. On the other hand, green synthesis methods, in harmony with the growing emphasis on sustainable practices in drug discovery, offer a more environmentally friendly alternative. Green synthesis typically involves the use of eco-friendly reagents, solvents, and energy-efficient processes, resulting in reduced environmental impact and improved resource efficiency. Overall, pyrazolic chalcone derivatives represent a promising class of compounds with significant potential for therapeutic applications.

Insight into the therapeutic potential of pyrazole-thiazole hybrids: A comprehensive review

Several pyrazole-thiazole hybrids featuring two potentially bioactive pharmacophores with or without linker have been synthesized using the molecular hybridization approach as target structures by medicinal chemists to modulate multiple drug targets simultaneously. The presented review aims to provide an overview of the diversified and wide array of pharmacological activities of these hybrids bestowing anticancer, antifungal, antibacterial, analgesic, anti-inflammatory, antioxidant, antitubercular, antiviral, antiparasitic, and miscellaneous activities. The structure-activity relationships and potential mechanism of action are also reviewed to shed light on the development of more effective and biotargeted candidates. This review focuses on the latest research advances in the biological profile of pyrazole-thiazole hybrids reported from 2015 to the present, providing medicinal researchers with a comprehensive platform to rationally design and develop more promising pyrazole-thiazole hybrids.

Synthesis, characterization, and evaluation of pyrimidinone-linked thiazoles: DFT analysis, molecular docking, corrosion inhibition, and bioactivity studies

The paper describes the construction of a new series of pyrimidinone-linked thiazole derivatives through bromination of the initial Biginelli reaction product followed by the Hantzsch thiazole synthesis route. Various analytical techniques, including FT-IR, 1H NMR, 13C NMR, and LCMS analysis, were employed to confirm the formation of the products. The synthesized compounds were primarily evaluated for their antibacterial activity, with a specific focus on their IC50 values. Compound 4c demonstrated the most potent efficacy, displaying MIC and MBC values that varied from 0.23 to 0.71 mg/mL and 0.46-0.95 mg/mL, respectively. The anti-inflammatory potential was also observed in analogs 4a and 4c with marked activity in the 33.2-82.9 μM concentration range. Moreover, compounds 4a, and 4c demonstrated strong antioxidant effects, as reflected by their excellent IC50 values of 38.6-43.5 μM respectively. DFT investigation showed that B. cereus was more susceptible, and E. coli was more resistant, with chloro-substituted compounds exhibiting potential reactivity. Some molecules with chloro-substituents showed promising results in density functional theory when compared to other substituents. In addition, the molecules underwent a corrosion study and demonstrated a high level of inhibition efficiency (4c) in comparison to other molecules. Further in silico studies of the synthesized thiazoles confirmed the good interactions with the target.

Facile benzothiazole-triazole based thiazole derivatives as novel thymidine phosphorylase and α-glucosidase inhibitors: Experimental and computational approaches

The present study reports the new thiazole (A-L) derivatives based on benzothiazole fused triazole which were synthesized and assessed against thymidine phosphorylase and α-glucosidase enzymes. Several compounds with the same basic structure but different substituents were found to have high activity against the targeted enzymes, while others with the same basic skeleton but different substituents were found to have medium to low activity among the members of tested series. These analogs showed a varied range of inhibition in both case thymidine phosphorylase and alpha glucosidase, A (IC50 = 7.20 ± 0.30 µM and IC50 = 1.30 ± 0.70 µM), B (IC50 = 8.80 ± 0.10 µM and IC50 = 2.10 ± 0.30 µM), C (IC50 = 8.90 ± 0.40 µM and IC50 = 3.20 ± 0.20 µM) and thiazole containing analogs such as G (IC50 = 11.10 ± 0.20 µM and IC50 = 7.80 ± 0.20 µM) and H (IC50 = 12.30 ± 0.30 µM and IC50 = 6.30 ± 0.20 µM). When compared with standard drugs 7-Deazaxanthine, 7DX (IC50 = 10.60 ± 0.50 µM) and acarbose (IC50 = 4.30 ± 0.30 µM) respectively. These analogs were also subjected to molecular docking studies which indicated the binding interaction of molecules with active sites of the enzyme and strengthen the drug profile of these compounds. ADMET studies also predict the drug-like properties of these compounds, with no violations of drug likeness rules.

Synthesis of 4-functionalized pyrazoles via oxidative thio- or selenocyanation mediated by PhICl2 and NH4SCN/KSeCN

A series of 4-thio/seleno-cyanated pyrazoles was conveniently synthesized from 4-unsubstituted pyrazoles using NH4SCN/KSeCN as thio/selenocyanogen sources and PhICl2 as the hypervalent iodine oxidant. This metal-free approach was postulated to involve the in situ generation of reactive thio/selenocyanogen chloride (Cl-SCN/SeCN) from the reaction of PhICl2 and NH4SCN/KSeCN, followed by an electrophilic thio/selenocyanation of the pyrazole skeleton.

N-Heterocycles as Promising Antiviral Agents: A Comprehensive Overview

Viruses are a real threat to every organism at any stage of life leading to extensive infections and casualties. N-heterocycles can affect the viral life cycle at many points, including viral entrance into host cells, viral genome replication, and the production of novel viral species. Certain N-heterocycles can also stimulate the host's immune system, producing antiviral cytokines and chemokines that can stop the reproduction of viruses. This review focused on recent five- or six-membered synthetic N-heterocyclic molecules showing antiviral activity through SAR analyses. The review will assist in identifying robust scaffolds that might be utilized to create effective antiviral drugs with either no or few side effects.

Synthesis, In Silico Study, and In Vitro Antifungal Activity of New 5-(1,3-Diphenyl-1H-Pyrazol-4-yl)-4-Tosyl-4,5-Dihydrooxazoles

The increase in multi-drug resistant Candida strains has caused a sharp rise in life-threatening fungal infections in immunosuppressed patients, including those with SARS-CoV-2. Novel antifungal drugs are needed to combat multi-drug-resistant yeasts. This study aimed to synthesize a new series of 2-oxazolines and evaluate the ligands in vitro for the inhibition of six Candida species and in silico for affinity to the CYP51 enzymes (obtained with molecular modeling and protein homology) of the same species. The 5-(1,3-diphenyl-1H-pyrazol-4-yl)-4-tosyl-4,5-dihydrooxazoles 6a-j were synthesized using the Van Leusen reaction between 1,3-diphenyl-4-formylpyrazoles 4a-j and TosMIC 5 in the presence of K2CO3 or KOH without heating, resulting in short reaction times, high compound purity, and high yields. The docking studies revealed good affinity for the active site of the CYP51 enzymes of the Candida species in the following order: 6a-j > 4a-j > fluconazole (the reference drug). The in vitro testing of the compounds against the Candida species showed lower MIC values for 6a-j than 4a-j, and for 4a-j than fluconazole, thus correlating well with the in silico findings. According to growth rescue assays, 6a-j and 4a-j (like fluconazole) inhibit ergosterol synthesis. The in silico toxicity assessment evidenced the safety of compounds 6a-j, which merit further research as possible antifungal drugs.

Development of benzaldehyde-pyrazoline hybrids for functionalization of polymers with fluorescent pendant moieties

Compounds with a pyrazoline scaffold are useful as sensors for fluorescence detection of different types of analytes. Recovery of a pyrazoline-based sensor with a view to use it recurrently would be more facile when the sensing molecule is attached to a solid support. A reaction sequence has been designed to synthesize two benzaldehyde-pyrazoline hybrids as examples of a hitherto unknown type of compounds to be employed for the potential derivatization of polymers containing primary amino groups through azomethine formation. All intermediates, including the fairly unstable N1 -unsubstituted pyrazolines, along with the target compounds have been structurally characterized, with an emphasis on their particular NMR features. Examination of the photophysical properties of these benzaldehyde-pyrazoline hybrids showed that, despite the shortening of the extended N1-N2-C3 conjugated system common to 1,3,5-triarylpyrazolines through the replacement of the aryl at N1 by an aryloxyacetyl moiety, the novel compounds exhibit emission maxima at approximately 350 nm. Moreover, the introduction of a moderately electron-withdrawing substituent such as chlorine in the phenyl at C3 of pyrazoline leads to an amplification of fluorescence intensity.

Recent advances in the synthesis and medicinal perspective of pyrazole-based α-amylase inhibitors as antidiabetic agents

Diabetes is a serious health threat across the globe, claiming millions of lives worldwide. Among the various strategies employed, inhibition of α-amylase is a therapeutic protocol for the management of Type 2 diabetes mellitus. α-Amylase is a crucial enzyme involved in the breakdown of dietary starch into simpler units. However, the clinically used α-amylase inhibitors have various drawbacks. Therefore, design and development of novel α-amylase inhibitors have gained significant attention. The pyrazole motif has been identified as a versatile scaffold in medicinal chemistry, and recent studies have led to the identification of various pyrazole-based α-amylase inhibitors. This review compiles therapeutic implications of pyrazole-appended α-amylase inhibitors; their synthesis, biological activities, structure-activity relationships and molecular docking studies are discussed.

Synthesis, in vitro potency of inhibition, enzyme kinetics and in silico studies of quinoline-based α-glucosidase inhibitors

Diabetes mellitus is a multifactorial global health disorder that is rising at an alarming rate. One effective therapeutic approach for controlling hyperglycemia associated with type-2 diabetes is to target α-glucosidase, which catalyzes starch hydrolysis in the intestine. In an attempt to find potential α-glucosidase inhibitors, a series of twenty new quinoline linked benzothiazole hybrids (8a-t) were synthesized in good yields from suitable reaction procedures and their chemical structures were analyzed by 1HNMR, 13CNMR, IR, and ESI-MS analysis. The synthesized derivatives further screened for their activity against α-glucosidase. Among them, compounds 8b, 8h, 8n and 8o exhibited remarkable α-glucosidase inhibitory activity with IC50 values ranging from 38.2 ± 0.3 to 79.9 ± 1.2 µM compared with standard drug acarbose (IC50 = 750.0 ± 2.0 µM). Enzyme kinetic studies of the most active compound (8h) indicated a non-competitive inhibition with Ki value of 38.2 µM. Moreover, the homology modeling, molecular docking and molecular dynamics simulation studies were conducted to reveal key interactions between the most active compound 8h and the targeted enzyme. These results are complementary to the experimental observations. In order to predict the druggability of the novel derivatives, the pharmacokinetic properties were also applied. These findings could be useful for the design and development of new α-glucosidase inhibitors.

Pyrazoles as Anti-inflammatory and Analgesic Agents: In-vivo and In-silico Studies

BACKGROUND

Pyrazole is a well-known nucleus in the pharmacy field with a wide range of other activities in addition to anti-inflammatory and analgesic, i.e., anticonvulsant, antiviral, and anticancer activities. There are well-known marketed drugs having pyrazole moiety as celecoxib, and lonazolac as COX-II inhibitors.

AIMS

We aim to synthesize better anti-inflammatory than existing ones. Thiophene is also known for its analgesic and anti-inflammatory action. Thus, the fusion of both gives better anti-inflammatory agents. In the present studies, derivatives from two series of pyrazole were prepared by reacting substituted chalcone (3a-3f) derivatives prepared from 2-acetyl thiophene. They substituted aromatic aldehydes with phenyl hydrazine to form (5a-5f) and with 2, 4-dinitro phenyl hydrazine giving compounds (6a-6f) separately.

METHODS

Purified and characterized pyrazoles have been analyzed for in-vivo analgesic and anti-inflammatory activities by using standard methods. Compounds 5e, 5f, and 6d were proved to be potent analgesics and series (5a-5f) was found to have anti-inflammatory action, which was further validated using docking and ADME studies.

RESULTS

The ADME profile of synthesized compounds was found to be satisfactory.

CONCLUSION

The synthesized compounds can serve as lead for further drug designing.

A Literature Review Focusing on the Antiviral Activity of [1,2,4] and [1,2,3]-triazoles

Out of a variety of heterocycles, triazole scaffolds have been shown to play a significant part in a wide array of biological functions. Many drug compounds containing a triazole moiety with important antimicrobial, anticancer and antidepressant properties have been commercialized. In addition, the triazole scaffold exhibits remarkable antiviral activity either incorporated into nucleoside analogs or non-nucleosides. Many synthetic techniques have been produced by scientists around the world as a result of their wide-ranging biological function. In this review, we have tried to summarize new synthetic methods produced by diverse research groups as well as provide a comprehensive description of the function of [1,2,4] and [1,2,3]-triazole derivatives as antiviral agents. Antiviral triazole compounds have been shown to target a wide variety of molecular proteins. In addition, several strains of viruses, including the human immunodeficiency virus, SARS virus, hepatitis B and C viruses, influenza virus, Hantavirus, and herpes virus, were discovered to be susceptible to triazole derivatives. This review article covered the reports for antiviral activity of both 1,2,3- and 1,2,4-triazole moieties up to 2022.

Novel D-modified heterocyclic androstane derivatives as potential anticancer agents: Synthesis, characterization, in vitro and in silico studies

Cancer remains a major health concern worldwide. The most frequently diagnosed types of cancer are caused by abnormal production or action of steroid hormones. In the present study, the synthesis and structural characterization of new heterocyclic androstane derivatives with D-homo lactone, 17α-(pyridine-2''-ylmethyl) or 17(E)-(pyridine-2''-ylmethylidene) moiety are presented. All compounds were evaluated for their anti-proliferative activity against HeLa cervical cancer cell line and non-cancerous kidney MDCK cells, where A-homo lactam compound 9A showed the greatest selectivity. Based on in vitro binding assays, N-formyl lactam compound 18 appeared to be the strong and isoform-selective ligand for ERα, while compound 9A displayed binding affinity for the GR-LBD, but also inhibited aldo-keto reductase 1C4 enzyme. Out of four selected compounds, methylpyrazolo derivative 13 showed potential for aromatase binding, while in silico studies provided insight into experimentally confirmed protein-ligand interactions.

Department of pharmaceutical Chemistry, bharati Vidyapeeth’s College of pharmacy, Sector 8, C.b.D. belapur, Navi mumbai-400 614, maharashtra, India, Shinkar SS, Bhairi SR, Khedkar PM, Dhande SR, Jagdale DM. DESIGNING, SYNTHESIS AND BIOLOGICAL EVALUATION OF PYRAZOLINE DERIVATIVES TARGETING PANCREATIC CANCER CELLS

In continuation of the previous work based upon pyrazoline derivatives having cytotoxic activity, twenty-one 1,3,5-substituted pyrazoline derivatives were designed taking into consideration the important functional groups of methisazone, sorafenib and chalcone. the designed derivatives were screened using a preliminary molecular docking simulation study for evaluation of their binding interactions with receptor-2 of vascular endothelial growth factor, i.e., pDb ID: 3WZD. the synthesized derivatives were biologically evaluated for in vivo anti-angiogenic activity using adult zebrafish, its embryo, and in vitro anti-proliferative activity against pancreatic cancer mIA-pA-CA-2 cell line using the sulforhodamine b assay. Compound 5b emerged as a promising hit molecule as it manifested moderate in vitro cytotoxic activity. besides, its ability to inhibit zebrafish caudal fin regeneration with less phenotypical changes in zebrafish embryos suggests its promising potential against pancreatic cancer by VeGFR-2 inhibition as a mode of action.

Exploration of Thiourea-Based Scaffolds for the Construction of Bacterial Ureases Inhibitors

A series of 32 thiourea-based urease inhibitors were synthesized and evaluated against native bacterial enzyme and whole cells of Sporosarcina pasteurii and Proteus mirabilis strains. The proposed inhibitors represented structurally diverse thiosemicarbazones and thiocarbohydrazones, benzyl-substituted thiazolyl thioureas, 1H-pyrazole-1-carbothioamides, and dihydropirimidine-2(1H)-thiones. Kinetic characteristics with purified S. pasteurii enzyme determined low micromolar inhibitors within each structural group. (E)-2-(1-Phenylethylidene)hydrazine-1-carbothioamide 19 (Ki = 0.39 ± 0.01 μM), (E)-2-(4-methylbenzylidene)hydrazine-1-carbothioamide 16 (Ki = 0.99 ± 0.04 μM), and N'-((1E,2E)-1,3-diphenylallylidene)hydrazinecarbothiohydrazide 29 (Ki = 2.23 ± 0.19 μM) were used in modeling studies that revealed sulfur ion coordination of the active site nickel ion and hydrogen bonds between the amide group and the side chain of Asp363 and Ala366 carbonyl moiety. Whole-cell studies proved the activity of compounds in Gram-positive and Gram-negative microorganisms. Ureolysis control observed in P. mirabilis PCM 543 (e.g., IC50 = 304 ± 14 μM for 1-benzyl-3-(4-(4-hydroxyphenyl)thiazol-2-yl)thiourea 52) is a valuable achievement, as urease is recognized as a major virulence factor of this urinary tract pathogen.

Synthesis, antimicrobial and antioxidant activity of triazole, pyrazole containing thiazole derivatives and molecular docking studies on COVID-19

New series of biologically active triazole and pyrazole compounds containing 2, 4-disubstituted thiazole analogues (12a-l) were synthesized from p-hydroxy benzaldehyde and phenyl hydrazine in excellent yields and purity. All the synthesized compounds were unambiguously identified based on their spectral data analyses (IR, ¹H-NMR, ¹³C-NMR spectra, and HRMS). The final derivatives were evaluated for their in vitro anti-microbial activity after thorough purification. Among all the tested compounds, the compound 12e, 12f and 12 k possess the highest growth inhibitory activity at MIC values of 4.8, 5.1 and 4.0 μg/ml respectively. The antioxidant properties of these compounds demonstrated and revealed remarkable activity compared to the standard antioxidant by using the DPPH free radical-scavenging assay. Moreover, molecular docking studies to evaluate the probable interactions with the catalytic domain of the gram-positive S. aureus topoisomerase IV enzyme may provide new insights for developing these new hybrids as potential antimicrobial agents. The binding affinities of compounds 12a-l were ranging from - 10.0 to - 11.0 kcal/mol with topoisomerase IV enzyme and with COVID-19 main protease binding affinities are ranging from - 8.2 to - 9.3 kcal/mol. These docking studies reveal that the compounds 12a-l could be the best inhibitors for the novel SARS Cov-2 virus and have more future in discovery of potent drug candidates.

Antifungal Activities of Fluorinated Pyrazole Aldehydes on Phytopathogenic Fungi, and Their Effect on Entomopathogenic Nematodes, and Soil-Beneficial Bacteria

Fluoro-substituted pyrazoles have a wide range of biological activities, such as antibacterial, antiviral, and antifungal activities. The aim of this study was to evaluate the antifungal activities of fluorinated 4,5-dihydro-1H-pyrazole derivatives on four phytopathogenic fungi: Sclerotinia sclerotiorum, Macrophomina phaseolina, Fusarium oxysporum f. sp. lycopersici, and F. culmorum. Moreover, they were tested on two soil beneficial bacteria-Bacillus mycoides and Bradyrhizobium japonicum-as well as two entomopathogenic nematodes (EPNs)-Heterorhabditis bacteriophora and Steinernema feltiae. The molecular docking was performed on the three enzymes responsible for fungal growth, the three plant cell wall-degrading enzymes, and acetylcholinesterase (AChE). The most active compounds against fungi S. sclerotiorum were 2-chlorophenyl derivative (H9) (43.07% of inhibition) and 2,5-dimethoxyphenyl derivative (H7) (42.23% of inhibition), as well as H9 against F. culmorum (46.75% of inhibition). Compounds were shown to be safe for beneficial soil bacteria and nematodes, except for compound H9 on EPN H. bacteriophora (18.75% mortality), which also showed the strongest inhibition against AChE (79.50% of inhibition). The molecular docking study revealed that antifungal activity is possible through the inhibition of proteinase K, and nematicidal activity is possible through the inhibition of AChE. The fluorinated pyrazole aldehydes are promising components of future plant protection products that could be environmentally and toxicologically acceptable.

Synthesis and biological evaluation of 2,5-disubstituted furan derivatives containing 1,3-thiazole moiety as potential α-glucosidase inhibitors

α-Glucosidase, which is involved in the hydrolysis of carbohydrates to glucose and directly mediates blood glucose elevation, is a crucial therapeutic target for type 2 diabetes. In this work, 2,5-disubstituted furan derivatives containing 1,3-thiazole-2-amino or 1,3-thiazole-2-thiol moiety (III-01 ∼ III-30) were synthesized and screened for their inhibitory activity against α-glucosidase. α-Glucosidase inhibition assay demonstrated that all compounds had IC₅₀ in the range of 0.645-94.033 μM and more potent than standard inhibitor acarbose (IC₅₀ = 452.243 ± 54.142 µM). The most promising inhibitors of the two series were compound III-10 (IC₅₀ = 4.120 ± 0.764 μM) and III-24 (IC₅₀ = 0.645 ± 0.052 μM), respectively. Kinetic study and molecular docking simulation revealed that compound III-10 (Ki = 2.04 ± 0.72 μM) is a competitive inhibitor and III-24 (Ki = 0.44 ± 0.53 μM) is a noncompetitive inhibitor against α-glucosidase. Significantly, these two compounds showed nontoxicity towards HEK293, RAW264.7 and HepG2 cells, suggesting that compounds may be considered as a class of potential candidates for further developing novel antidiabetic drugs.

Pyrazole scaffold-based derivatives: A glimpse of α-glucosidase inhibitory activity, SAR, and route of synthesis

The α-glucosidase is a validated target to develop drugs for treating type 2 diabetes mellitus. The existing α-glucosidase inhibitors have certain shortcomings related to side effects and route of synthesis. Accordingly, it is inevitable to develop new chemical templates as α-glucosidase inhibitors. Pyrazole derivatives have a special place in medicinal chemistry because of various biological activities. Recently, pyrazole-based heterocyclic compounds have emerged as a promising scaffold to develop α-glucosidase inhibitors. This study focuses on the recently reported pyrazole-based α-glucosidase inhibitors, including their biological activity (in vivo, in vitro, and in silico), structure-activity relationship, and ways of synthesis. The literature revealed the development of several promising pyrazole-based α-glucosidase inhibitors and new synthetic routes for their preparation. The encouraging α-glucosidase inhibitory results of the pyrazole-based heterocyclic compounds make them an attractive target for further research. The authors also foresee the arrival of the pyrazole-based α-glucosidase inhibitors in clinical practice.

An efficient metal-free and catalyst-free C-S/C-O bond-formation strategy: synthesis of pyrazole-conjugated thioamides and amides

An operationally simple and metal-free approach is described for the synthesis of pyrazole-tethered thioamide and amide conjugates. The thioamides were generated by employing a three-component reaction of diverse pyrazole C-3/4/5 carbaldehydes, secondary amines, and elemental sulfur in a single synthetic operation. The advantages of this developed protocol refer to the broad substrate scope, metal-free and easy to perform reaction conditions. Moreover, the pyrazole C-3/5-linked amide conjugates were also synthesized via an oxidative amination of pyrazole carbaldehydes and 2-aminopyridines using hydrogen peroxide as an oxidant.

Pyrazoline scaffold: hit identification to lead synthesis and biological evaluation as antidiabetic agents

Background: Mining of novel scaffolds as potential DPP-IV inhibitors for future development of potential candidates as antidiabetic agents to address global issues. Methodology: The identified hit KB-10 from a previously reported study was taken as a lead for designing a library of analogues and screened initially based on in silico parameters and docking score. A series of selected (2[4-(1-acetyl-5-phenyl-4,5-dihydro-1H-pyrazol-3-yl)phenoxy]-1-phenylethanone derivatives were synthesized and evaluated through in vitro studies. Compounds KB-23, KB-22 and KB-06 were found to be as potent, with IC₅₀ values of 0.10 μM, 0.12 μM and 0.35 μM, respectively. They also showed promising antihyperglycemic potential in in vivo studies (oral glucose tolerance tests) in Wistar rats. Conclusion: This work establishes pyrazoline analogues KB-23, KB-22 and KB-06 as promising starting points for the development of potential antidiabetic agents.

Exploring the dual effect of novel 1,4-diarylpyranopyrazoles as antiviral and anti-inflammatory for the management of SARS-CoV-2 and associated inflammatory symptoms

COVID-19 and associated substantial inflammations continue to threaten humankind triggering death worldwide. So, the development of new effective antiviral and anti-inflammatory medications is a major scientific goal. Pyranopyrazoles have occupied a crucial position in medicinal chemistry because of their biological importance. Here, we report the design and synthesis of a series of sixteen pyranopyrazole derivatives substituted with two aryl groups at N-1 and C-4. The designed compounds are suggested to show dual activity to combat the emerging Coronaviruses and associated substantial inflammations. All compounds were evaluated for their in vitro antiviral activity and cytotoxicity against SARS-CoV infected Vero cells. As well, the in vitro assay of all derivatives against the SARS-CoV M^pro target was performed. Results revealed the potential of three pyranopyrazoles (22, 27, and 31) to potently inhibit the viral main protease with IC₅₀ values of 2.01, 1.83, and 4.60 μM respectively compared with 12.85 and 82.17 μM for GC-376 and lopinavir. Additionally, in vivo anti-inflammatory testing for the most active compound 27 proved its ability to reduce levels of two cytokines (TNF-α and IL-6). Molecular docking and dynamics simulation revealed consistent results with the in vitro enzymatic assay and indicated the stability of the putative complex of 27 with SARS-CoV-2 M^pro. The assessment of metabolic stability and physicochemical properties of 27 have also been conducted. This investigation identified a set of metabolically stable pyranopyrazoles as effective anti-SARS-CoV-2 M^pro and suppressors of host cell cytokine release. We believe that the new compounds deserve further chemical optimization and evaluation for COVID-19 treatment.

Synthesis of Spiro‐oxindole Analogs Engrafted Pyrazole Scaffold as Potential Alzheimer's Disease Therapeutics: Anti‐oxidant, Enzyme Inhibitory and Molecular Docking Approaches

About 19 spirooxindole analogs 8 a–s engrafted with pyrazole scaffolds were designed and constructed via [3+2] cycloaddition reaction (32CA) approach. The synthesized spirooxindole analogs was screened for anti‐cholinesterase against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) and antioxidant potentials against DPPH. The compounds 8 h and 8 i showed the strongest acetylcholine esterase (AChE) and butyrylcholinesterase (BChE) inhibition with IC50 values of 30 μg/mL respectively. The highest anti‐oxidant potential was demonstrated by compounds 8 p with IC50 values of 240 μg/mL, respectively. Molecular docking was used to study their interaction with the active site of enzymes.

Catalytic and Multicomponent Reactions for Green Synthesis of Some Pyrazolone Compounds and Evaluation as Antimicrobial Agents

A green synthetic approach and facile method was developed to produce pyrazole compounds (6a-d) by the reaction of ethyl acetoacetate (1), hydrazines (2a-d), and catalytic imidazole (3) in aqueous media. 4-Dicyanomethylene-2-pyrazoline-5-one derivatives (14a-d) were synthesized through the reaction of 2-pyrazoline-5-one derivatives (6a-d) with tetracyanoethylene (TCE) (7) by using catalytic imidazole (3) in an aqueous medium. Moreover, the 4-dicyanomethylene derivative (16) was obtained via treatment of 1-phenyl-3,5-pyrazolidinedione (15) with TCE (7). The spiropyrazoleoxirane derivatives (18 and 20) were prepared by treating the precursor 4-dicyanomethylene-2-pyrazoline-5-one derivative (14b) with hydrogen peroxide in various polar solvents under alkaline conditions. The spiropyrazole oxirane derivative (18) was used as a precursor for the design of functionalized pyrazolone derivatives (24 and 27a, b). The chemical structure of the novel designed derivatives was ascertained based on elemental analyses, mp, thin-layer chromatography, and spectral analyses. Furthermore, some of the synthesized derivatives were examined against different pathogenic bacterial and fungal strains. Their results demonstrated that some of them revealed notable antimicrobial activities.

Synthesis and In Silico Docking Study towards M-Pro of Novel Heterocyclic Compounds Derived from Pyrazolopyrimidinone as Putative SARS-CoV-2 Inhibitors

In addition to vaccines, antiviral drugs are essential in order to suppress COVID-19. Although some inhibitor candidates have been determined to target the SARS-CoV-2 protein, there is still an urgent need to continue researching novel inhibitors of the SARS-CoV-2 main protease 'Omicron P132H', a protein that has recently been discovered. In the present study, in the search for therapeutic alternatives to treat COVID-19 and its recent variants, we conducted a structure-based virtual screening using docking studies for a new series of pyrazolo[3,4-d]pyrimidin-4(5H)-one derivatives 5-13, which were synthesized from the condensation reaction of pyrazolopyrimidinone-hydrazide (4) with a series of electrophiles. Some significant ADMET predictions-in addition to the docking results-were obtained based on the types of interactions formed and the binding energy values were compared to the reference anti- SARS-CoV-2 redocked drug nirmatrelvir.

Pyrazole Scaffolds: Centrality in Anti-Inflammatory and Antiviral Drug Design

BACKGROUND

Pyrazole is a component of a diversity of bioactive heterocyclic congeners with a broad-spectrum range of biological and pharmacological uses. Designing novel pyrazole and its analogues, revealing new routes for synthesizing this nucleus, exploring various potencies of that heterocycles, and looking for possible applications of pyrazoles are all becoming more important due to their numerous potential applications.

OBJECTIVES

Pyrazole scaffolds have been proven to be successful as anti-viral and anti-inflammatory therapeutic against multiple targets like HSV-1, NNRTI, H1N1, CoX-1, and CoX-2. Due to this miscellany in the biotic area, this moiety has engrossed the consideration of many scientists to study chemistry and pharmacological profile.

RESULTS

The review encompasses pyrazole having various scaffolds with multiple biological activities and attempts have also been made to correlate their structure-activity relationship. Multiple pyrazole correspondents have been synthesized as lead molecules and performed valuation for their actions.

CONCLUSION

The incorporation of pyrazole with other pharmacophores in the molecule might lead to novel potent therapeutic agents that will further help in designing potent lead molecules.

NO in Viral Infections: Role and Development of Antiviral Therapies

Nitric oxide is a ubiquitous signaling radical that influences critical body functions. Its importance in the cardiovascular system and the innate immune response to bacterial and viral infections has been extensively investigated. The overproduction of NO is an early component of viral infections, including those affecting the respiratory tract. The production of high levels of NO is due to the overexpression of NO biosynthesis by inducible NO synthase (iNOS), which is involved in viral clearance. The development of NO-based antiviral therapies, particularly gaseous NO inhalation and NO-donors, has proven to be an excellent antiviral therapeutic strategy. The aim of this review is to systematically examine the multiple research studies that have been carried out to elucidate the role of NO in viral infections and to comprehensively describe the NO-based antiviral strategies that have been developed thus far. Particular attention has been paid to the potential mechanisms of NO and its clinical use in the prevention and therapy of COVID-19.

Synthesis, crystal structure, Hirshfeld surface investigation and comparative DFT studies of ethyl 2-[2-(2-nitrobenzylidene)hydrazinyl]thiazole-4-carboxylate

The ethyl 2-[2-(2-nitrobenzylidene)hydrazinyl]thiazole-4-carboxylate (1), a thiazole ester, was synthesized by refluxing 1-(2-nitrobenzylidene)thiosemicarbazide and ethyl bromopyruvate. The compound is characterized by spectrometric, spectroscopic and single crystal (SC-XRD) techniques. Non-covalent interactions that are responsible for crystal packing are explored by Hirshfeld surface analysis. All theoretical calculations were performed by DFT quantum chemical methods using 6-311G(d,p) and cc-pVTZ basis sets and compared. Theoretical harmonic frequencies of ethyl 2-[2-(2-nitrobenzylidene)hydrazinyl]thiazole-4-carboxylate (1) were optimized. Confirmation of hydrogen bonding sites was analyzed by molecular electrostatic potential (MEP) and Mulliken population analysis. The vibrational frequencies of characteristic functional groups and chemical shifts were found in good agreement with experimental assignments. Frontier molecular orbital (FMO) revealed relatively small HOMO–LUMO (highest occupied molecular orbital-lowest unoccupied molecular orbital) gape, which speaks off the nearly planar geometry and extended conjugation, as compared to the substituents with no conjugation possible. It has also been observed that –NO₂ substituent plays a vital role for this relatively small HOMO–LUMO gape and overall electronic properties when compared with similar thiazole carboxylates (2–6, Table 6). Ethyl 2-[2-(2-nitrobenzylidene)hydrazinyl]thiazole-4-carboxylate (1) was also evaluated for its anti-oxidant and anti-microbial activities.

Coordination complexes constructed from pyrazole-acetamide and pyrazole-quinoxaline: effect of hydrogen bonding on the self-assembly process and antibacterial activity

Two mononuclear coordination complexes of N-(2-aminophenyl)-2-(5-methyl-1H-pyrazol-3-yl)acetamide (L1), namely [Cd(L1)2Cl2] (C1) and [Cu(L1)2(C2H5OH)2](NO3)2 (C2) and one mononuclear complex [Fe(L2)2(H2O)2](NO3)2·2H2O (C3), obtained after in situ oxidation of L1, have been synthesized and characterized spectroscopically. As revealed by single-crystal X-ray diffraction, each coordination sphere made of two heterocycles is completed either by two chloride anions (in C1), two ethanol molecules (in C2) or two water molecules (in C3). The crystal packing analysis of C1, C2 and C3, revealed 1D and 2D supramolecular architectures, respectively, via various hydrogen bonding interactions, which are discussed in detail. Furthermore, evaluation in vitro of the ligands and their metal complexes for their antibacterial activity against Escherichia coli (ATCC 4157), Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 25923) and Streptococcus fasciens (ATCC 29212) strains of bacteria, revealed outstanding results compared to chloramphenicol, a well-known antibiotic, with a normalized minimum inhibitory concentration as low as 5 μg mL-1.

Design, Synthesis and Cytotoxicity of Thiazole-Based Stilbene Analogs as Novel DNA Topoisomerase IB Inhibitors

A series of new thiazole-based stilbene analogs were designed, synthesized and evaluated for DNA topoisomerase IB (Top1) inhibitory activity. Top1-mediated relaxation assays showed that the synthesized compounds possessed variable Top1 inhibitory activity. Among them, (E)-2-(3-methylstyryl)-4-(4-fluorophenyl)thiazole (8) acted as a potent Top1 inhibitor with high Top1 inhibition of ++++ which is comparable to that of CPT. A possible binding mode of compound 8 with Top1–DNA complex was further provided by molecular docking. An MTT assay against human breast cancer (MCF-7) and human colon cancer (HCT116) cell lines revealed that the majority of these compounds showed high cytotoxicity, with IC₅₀ values at micromolar concentrations. Compounds 8 and (E)-2-(4-tert-butylstyryl)-4-(4-fluorophenyl)thiazole (11) exhibited the most potent cytotoxicity with IC₅₀ values of 0.78 and 0.62 μM against MCF-7 and HCT116, respectively. Moreover, the preliminary structure–activity relationships of thiazole-based stilbene analogs was also discussed.

Microwave assisted C–S cross-coupling reaction from thiols and 2-(4-bromo phenyl)-benzothiazole employed by CuI in acetonitrile

A microwave assisted C–S and C–Se cross-coupling reaction was carried out in acetonitrile employing commercially available, low-cost CuI as the catalyst.

Synthesis of Spirooxindole Analogs Tethered Pyrazole Scaffold as Acetylcholinesterase Inhibitors

A new series of spirooxindole analogs tethered pyrazole scaffold constructed via [3+2] cycloaddition (32CA) reaction starting from the new chalcone named (E)‐3‐(5‐chloro‐3‐methyl‐1‐phenyl‐1H‐pyrazol‐4‐yl)‐1‐(5‐methyl‐1‐phenyl‐1H‐pyrazol‐4‐yl)prop‐2‐en‐1‐one which confirmed by single crystal X‐ray diffraction analysis. Synthesized spirooxindole analogs were evaluated for their neuroprotection through the inhibition of acetylcholine esterase enzyme using Ellman's method. Compounds 9 w, 9 e and 9 x showed the strongest acetylcholine esterase inhibition (AChEI) with IC50 values of 5.7, 7.8 and 8.3 μM, respectively. Obviously, the incorporation of NO2 group into isatin 5th position and N‐methylglycine (sarcosine) play a crucial role for the activity which lead to compound 9 w had the most potent inhibitory activity with IC50 value of 5.7 μM. Molecular docking was used to study their interaction with the active site of hAChE. These 32CA reactions takes place via a one‐step mechanism with a high polar character as a consequence of the supernucleophilic character of azomethine yildes and the strong electrophilic character of ethylenes.

Construction of Spirooxindole Analogues Engrafted with Indole and Pyrazole Scaffolds as Acetylcholinesterase Inhibitors

Twenty-five new hits of spirooxindole analogs 8a-y engrafted with indole and pyrazole scaffolds were designed and constructed via a [3+2]cycloaddition (32CA) reaction starting from three components: new chalcone-based indole and pyrazole scaffolds 5a-d, substituted isatins 6a-c, and secondary amines 7a-d. The potency of the compounds were assessed in modulating cholinesterase (AChE) activity using Ellman's method. Compounds 8i and 8y showed the strongest acetylcholine esterase inhibition (AChEI) with IC50 values of 24.1 and 27.8 μM, respectively. Molecular docking was used to study their interaction with the active site of hAChE.