Synthesis of novel coumarin appended bis(formylpyrazole) derivatives: Studies on their antimicrobial and antioxidant activities

Latest developments in coumarin-based anticancer agents: mechanism of action and structure-activity relationship studies

Many researchers around the world are working on the development of novel anticancer drugs with different mechanisms of action. In this case, coumarin is a highly promising pharmacophore for the development of novel anticancer drugs. Besides, the hybridization of this moiety with other anticancer pharmacophores has emerged as a potent breakthrough in the treatment of cancer to decrease its side effects and increase its efficiency. This review aims to provide a comprehensive overview of the recent development of coumarin derivatives and their application as novel anticancer drugs. Herein, we highlight and describe the largest number of research works reported in this field from 2015 to August 2023, along with their mechanisms of action and structure-activity relationship studies, making this review different from the other review articles published on this topic to date.

Unravelling the synthetic and therapeutic aspects of five, six and fused heterocycles using Vilsmeier-Haack reagent

The aim of this review is to encapsulate the synthetic protocols and medicinal aspects of a wide range of heterocyclic compounds using the Vilsmeier-Haack (V. H.) reagent. These derivatives act as excellent precursors having different aryl ring functionalities and could be used for the synthesis of a variety of heterocyclic scaffolds. The V. H. reagent, a versatile reagent in organic chemistry, is used to formylate various heterocyclic compounds of medicinal interest. Due to the different chemical interactions, efficacy, and potency of V. H. reagents, plenty of heterocyclic compounds can be synthesized which serve as a constituent in various novel medications and acts as a bridge between biology and chemistry. These carboxylate moieties can effectively cooperate as precursors for several multi-component reactions (MCR) including Strecker synthesis, Bucherer-Berg reaction and post-MCR cyclization, modified variants with various pharmaceutical applications such as anti-tumor, anti-convulsant, anti-chitosomal and so on.

Coumarin Based Fluorescent Probe for Detecting Heavy Metal Ions

Heavy metals such as Iron, Copper, and Zinc are micro-essential trace metal and involve animportant biological role, but it quickly turns toxic at exceeding the permissible limit, causing gastrointestinal irritation, liver, bone, and kidney damage, as well as disorders including Wilson's, Parkinson's, and Alzheimer's. It is important to detect the metal ions as well as their concentration quickly and affordable cost using organic probes. Among the organic probes,the coumarin fluorescent probe shows a very prominent candidate with heavy metal ions. Therefore, in the present review, we reviewed the very recent literature the identify the heavy metals using modified coumarin fluorescent probes. Readers will get information quickly about the method of preparation of modified coumarin core and their use as fluorescent probes with heavy metals using absorption and emission spectroscopic methods along with the probable mechanistic pathway of detection.

Designing Potent α-Glucosidase Inhibitors: A Synthesis and QSAR Modeling Approach for Biscoumarin Derivatives

Nineteen biscoumarins were synthesized, well-characterized, and evaluated against α-glucosidases in vitro. Of these, six compounds (10, 12, 16, and 17-19) were newly synthesized and not previously reported in the chemical literature. The majority of the synthesized derivatives demonstrated significant inhibitory activity. A quantitative structure-activity relationship (QSAR) model was developed, revealing a strong correlation between the anti-α-glucosidase activity and selected molecular descriptors. Based on this model, two new compounds (18 and 19) were designed, which exhibited the strongest inhibition with IC₅₀ values of 0.62 and 1.21 μM, respectively, when compared to the positive control (acarbose) with an IC₅₀ value of 93.63 μM. Enzyme kinetic studies of compounds 18 and 19 revealed their competitive inhibition with K_i values of 3.93 and 1.80 μM, respectively. Computational studies demonstrated that compound 18 could be inserted into the original binding site (OBS) of α-glucosidase MAL12 and form multiple hydrophobic interactions with nearby amino acids, with the bromo group playing an essential role in enhancing the binding strength and stability at the OBS of the enzyme based on the quantum mechanical calculations using the fragment molecular orbital method. These findings provide valuable insights into the design of potent α-glucosidase inhibitors, which may have potential therapeutic applications in the treatment of diabetes and related diseases.

Study on effective synthesis of 7-hydroxy-4-substituted coumarins

Many coumarin derivatives have good biological activity and application value in fluorescent probes. Therefore, synthetic routes to coumarin derivatives have also attracted the attention of many research groups. In this work, based on the Pechmann coumarin synthesis method, the influence of various Lewis acids on the reaction was discussed, and the optimal synthesis conditions of 7-hydroxy-4-substituted coumarins were explored. Based on the experimental results, a possible mechanism was proposed, which provides a reference for future industrialized production of coumarins.

Molecular Insights into Coumarin Analogues as Antimicrobial Agents: Recent Developments in Drug Discovery

Simple Summary

Coumarins are a large family of benzopyrones, and more than 1300 coumarins have been reported to date. Natural, as well as synthetic, coumarins have demonstrated a diverse activity spectrum. On the other hand, the demands of the current health scenario witnessing morbidity and mortality due to microbial infections and multidrug-resistant bacterial strains, the well-reported phytochemical coumarin can be of interest. Some of the well-reported coumarin analogues as antimicrobial agents include β-lactum derivatives, coumarin-based 1,2,3-triazole compounds, the miconazole analogue, coumarin-substituted pyrazole hybrids, pyranocoumarin, coumarin−sulphonamide hybrids, pyranocoumarins, coumarin−sulphonamide derivatives, chromenylpyrazoles candidates, 3-amidocoumarins analogues, uracil−coumarin hybrids, indolinedione−coumarin hybrids, coumarin−imidazole hybrids, coumarin-fused pyrazolones and methyl thiazole derivatives, coumarin−theophylline hybrids, etc. In the present review, several methods for the synthesis of coumarin derivatives as antimicrobial agents are reported, along with structure−activity relationship (SAR) studies focusing on the developments reported since 2016.

Abstract

A major global health risk has been witnessed with the development of drug-resistant bacteria and multidrug-resistant pathogens linked to significant mortality. Coumarins are heterocyclic compounds belonging to the benzophenone class enriched in different plants. Coumarins and their derivatives have a wide range of biological activity, including antibacterial, anticoagulant, antioxidant, anti-inflammatory, antiviral, antitumour, and enzyme inhibitory effects. In the past few years, attempts have been reported towards the optimization, synthesis, and evaluation of novel coumarin analogues as antimicrobial agents. Several coumarin-based antibiotic hybrids have been developed, and the majority of them were reported to exhibit potential antibacterial effects. In the present work, studies reported from 2016 to 2020 about antimicrobial coumarin analogues are the focus. The diverse biological spectrum of coumarins can be attributed to their free radical scavenging abilities. In addition to various synthetic strategies developed, some of the structural features include a heterocyclic ring with electron-withdrawing/donating groups conjugated with the coumarin nucleus. The suggested structure−activity relationship (SAR) can provide insight into how coumarin hybrids can be rationally improved against multidrug-resistant bacteria. The present work demonstrates molecular insights for coumarin derivatives having antimicrobial properties from the recent past. The detailed SAR outcomes will benefit towards leading optimization during the discovery and development of novel antimicrobial therapeutics.

Research progress of coumarins and their derivatives in the treatment of diabetes

Diabetes is a group of metabolic diseases characterised by chronic hyperglycaemia caused by multiple causes, which is caused by insulin secretion and/or utilisation defects. It is characterised by increased fasting and postprandial blood glucose levels due to insulin deficiency or insulin resistance. It is reported that the harm of diabetes mainly comes from its complications, and the cardiovascular disease caused by diabetes is the primary cause of its harm. China has the largest number of diabetic patients in the world, and the prevention and control of diabetes are facing great challenges. In recent years, many kinds of literature have been published abroad, which have proved that coumarin and its derivatives are effective in the treatment of diabetic complications such as nephropathy and cardiovascular disease. In this paper, the types of antidiabetic drugs and the anti-diabetic mechanism of coumarins were reviewed.

Coumarins and Gastrointestinal Cancer: A New Therapeutic Option?

Cancers of the gastrointestinal (GI) tract are often life-threatening malignancies, which can be a severe burden to the health care system. Globally, the mortality rate from gastrointestinal tumors has been increasing due to the lack of adequate diagnostic, prognostic, and therapeutic measures to combat these tumors. Coumarin is a natural product with remarkable antitumor activity, and it is widely found in various natural plant sources. Researchers have explored coumarin and its related derivatives to investigate their antitumor activity, and the potential molecular mechanisms involved. These mechanisms include hormone antagonists, alkylating agents, inhibitors of angiogenesis, inhibitors of topoisomerase, inducers of apoptosis, agents with antimitotic activity, telomerase inhibitors, inhibitors of human carbonic anhydrase, as well as other potential mechanisms. Consequently, drug design and discovery scientists and medicinal chemists have collaborated to identify new coumarin-related agents in order to produce more effective antitumor drugs against GI cancers. Herein, we summarize the therapeutic effects of coumarin and its derivatives against GI cancer.

New 1,2,3-Triazole-Appended Bis-pyrazoles: Synthesis, Bioevaluation, and Molecular Docking

The present work describes design of a small library of new 1,2,3-triazole-appended bis-pyrazoles by using a molecular hybridization approach, and the synthesized hybrids were evaluated for their antifungal activity against different fungal strains, namely, Candida albicans, Cryptococcus neoformans, Candida glabrata, Candida tropicalis, Aspergillus niger, and Aspergillus fumigatus. All the compounds exhibited broad-spectrum activity against the tested fungal strains with excellent minimum inhibitory concentration values. The molecular docking study against sterol 14α-demethylase (CYP51) could provide valuable insights into the binding modes and affinity of these compounds. Furthermore, these compounds were also evaluated for their antioxidant activity, which also resulted in promising data.

Deciphering the detailed structure-activity relationship of coumarins as Monoamine oxidase enzyme inhibitors-An updated review

In the last few years, Monoamine oxidase (MAO) have emerged as a target for the treatment of many neurodegenerative diseases including anxiety, depression, Alzheimer's, and Parkinson's diseases. The MAO inhibitors especially selective and reversible inhibitors of either of the isoenzymes (MAO-A & MAO-B) have been given more attention as both the form have different therapeutic properties and hence can be used for different neurological disorders. The lack of selective and reversible inhibitors available for both the enzymes and severity of the neuronal disorder in society have opened a new door to the researchers to carry out large and dedicated researches in this field. Among the several classes of the molecule as the inhibitors, coumarins hold a rank as a potent scaffold with its ease of synthesis, high therapeutic potential, and reversibility in inhibiting MAOs. The current review is an update of the research in the field that covers the works during the last six years (2014-2020) with a major focus on the SAR of the coumarin derivatives including synthetic, natural, and hybrids of coumarins with FDA-approved drugs.

Optimization of Fermentation Process of Pomegranate Peel and Schisandra Chinensis and the Biological Activities of Fermentation Broth: Antioxidant Activity and Protective Effect Against H2O2-induced Oxidative Damage in HaCaT Cells

In this study, the lactobacillus fermentation process of pomegranate (Punica granatum L.) peel and Schisandra chinensis (Turcz.) Baill (PP&SC) was optimized by using the response surface method (RSM) coupled with a Box-Behnken design. The optimum fermentation condition with the maximal yield of ellagic acid (99.49 ± 0.47 mg/g) was as follows: 1:1 (w:w) ratio of pomegranate peel to Schisandra chinensis, 1% (v:v) of strains with a 1:1 (v:v) ratio of Lactobacillus Plantarum to Streptococcus Thermophilus, a 37 °C fermentation temperature, 33 h of fermentation time, 1:20 (g:mL) of a solid–liquid ratio and 3 g/100 mL of a glucose dosage. Under these conditions, the achieved fermentation broth (FB) showed stronger free radical scavenging abilities than the water extract (WE) against the ABTS⁺, DPPH, OH⁻ and O₂⁻ radicals. The cytotoxicity and the protective effect of FB on the intracellular ROS level in HaCaT cells were further detected by the Cell Counting Kit-8 (CCK-8) assay. The results showed that FB had no significant cytotoxicity toward HaCaT cells when its content was no more than 8 mg/mL. The FB with a concentration of 8 mg/mL had a good protective effect against oxidative damage, which can effectively reduce the ROS level to 125.94% ± 13.46% (p < 0.001) compared with 294.49% ± 11.54% of the control group in H₂O₂-damaged HaCaT cells. The outstanding antioxidant ability and protective effect against H₂O₂-induced oxidative damage in HaCaT cells promote the potential for the FB of PP&SC as a functional raw material of cosmetics.

Antiviral Activity of Isoimperatorin Against Influenza A Virus in vitro and its Inhibition of Neuraminidase

Influenza A virus (IAV) poses a severe threat to human health and is a major public health problem worldwide. As global anti-influenza virus drug resistance has increased significantly, there is an urgent need to develop new antiviral drugs, especially drugs from natural products. Isoimperatorin, an active natural furanocoumarin, exhibits a broad range of pharmacologic activities including anticoagulant, analgesic, anti-inflammatory, antibacterial, anti-tumor, and other pharmacological effects, so it has attracted more and more attention. In this study, the antiviral and mechanistic effects of isoimperatorin on influenza A virus in vitro were studied. Isoimperatorin illustrated a broad-spectrum antiviral effect, especially against the A/FM/1/47 (H1N1), A/WSN/33 (H1N1, S31N, amantadine resistant), A/Puerto Rico/8/34 (H1N1), and A/Chicken/Guangdong/1996 (H9N2) virus strains. The experimental results of different administration modes showed that isoimperatorin had the best antiviral activity under the treatment mode. Further time-of-addition experiment results indicated that when isoimperatorin was added at the later stage of the virus replication cycle (6–8 h, 8–10 h), it exhibited an effective antiviral effect, and the virus yield was reduced by 81.4 and 84.6%, respectively. In addition, isoimperatorin had no effect on the expression of the three viral RNAs (mRNA, vRNA, and cRNA). Both the neuraminidase (NA) inhibition assay and CETSA demonstrated that isoimperatorin exerts an inhibitory effect on NA-mediated progeny virus release. The molecular docking experiment simulated the direct interaction between isoimperatorin and NA protein amino acid residues. In summary, isoimperatorin can be used as a potential agent for the prevention and treatment of influenza A virus.

An Overview of Coumarin as a Versatile and Readily Accessible Scaffold with Broad-Ranging Biological Activities

Privileged structures have been widely used as an effective template for the research and discovery of high value chemicals. Coumarin is a simple scaffold widespread in Nature and it can be found in a considerable number of plants as well as in some fungi and bacteria. In the last years, these natural compounds have been gaining an increasing attention from the scientific community for their wide range of biological activities, mainly due to their ability to interact with diverse enzymes and receptors in living organisms. In addition, coumarin nucleus has proved to be easily synthetized and decorated, giving the possibility of designing new coumarin-based compounds and investigating their potential in the treatment of various diseases. The versatility of coumarin scaffold finds applications not only in medicinal chemistry but also in the agrochemical field as well as in the cosmetic and fragrances industry. This review is intended to be a critical overview on coumarins, comprehensive of natural sources, metabolites, biological evaluations and synthetic approaches.

Overview on developed synthesis procedures of coumarin heterocycles

Considering highly valuable biological and pharmaceutical properties of coumarins, the synthesis of these heterocycles has been considered for many organic and pharmaceutical chemists. This review includes the recent research in synthesis methods of coumarin systems, investigating their biological properties and describing the literature reports for the period of 2016 to the middle of 2020. In this review, we have classified the contents based on co-groups of coumarin ring. These reported methods are carried out in the classical and non-classical conditions particularly under green condition such as using green solvent, catalyst and other procedures.

Unveiling the Different Chemical Reactivity of Diphenyl Nitrilimine and Phenyl Nitrile Oxide in [3+2] Cycloaddition Reactions with (R)-Carvone through the Molecular Electron Density Theory

The [3+2] cycloaddition (32CA) reactions of diphenyl nitrilimine and phenyl nitrile oxide with (R)-carvone have been studied within the Molecular Electron Density Theory (MEDT). Electron localisation function (ELF) analysis of these three-atom-components (TACs) permits its characterisation as carbenoid and zwitterionic TACs, thus having a different reactivity. The analysis of the conceptual Density Functional Theory ( DFT) indices accounts for the very low polar character of these 32CA reactions, while analysis of the DFT energies accounts for the opposite chemoselectivity experimentally observed. Topological analysis of the ELF along the single bond formation makes it possible to characterise the mechanisms of these 32CA reactions as cb- and zw-type. The present MEDT study supports the proposed classification of 32CA reactions into pdr-, pmr-, cb- and zw-type, thus asserting MEDT as the theory able to explain chemical reactivity in Organic Chemistry.

Recent Advances in the Synthesis of Coumarin Derivatives from Different Starting Materials

The study of coumarin dates back to 1820 when coumarin was first extracted from tonka bean by Vogel. Compounds containing coumarin backbone are a very important group of compounds due to their usage in pharmacy and medicine. Properties and biological activities of coumarin derivatives have a significant role in the development of new drugs. Therefore, many different methods and techniques are developed in order to synthesize coumarin derivatives. Coumarin derivatives could be obtained from different starting materials with various methods but with big differences in yield. This review summarized various methods, techniques and reaction conditions for synthesis of coumarins from different compounds such as aldehydes, phenols, ketones and carboxylic acids.

Microwave-assisted synthesis, biological evaluation and molecular docking studies of new coumarin-based 1,2,3-triazoles

Coumarin-based 1,4-disubstituted 1,2,3-triazole derivatives were synthesized using a highly efficient, eco-friendly protocol via a copper(i)-catalyzed click reaction between various substituted arylazides and terminal alkynes.

Sulfamic acid incorporated HKUST-1: a highly active catalyst and efficient adsorbent

Herein we introduce an effective approach for incorporating sulfamic acid (SA) into HKUST-1. The synthesized materials have been characterized using XRD, XPS, BET, FT-IR, SEM, EDX and TEM. The X-ray diffraction pattern of SA@HKUST-1 is analogous to that of parent HKUST-1 in line shape and d-spacing, proving that chemical modification could be obtained without damage to structural solidity. The XPS spectra confirmed successful sulfonation, due to the single S 2p peak being attributable to SO₃H groups at 168 eV. Catalytic efficiency was studied for 7-hydroxy-4-methyl coumarin and 3,4-dihydropyrimidinone synthesis and it was found to be highly dependent on the amount of SA loaded over HKUST-1. Moreover, the adsorptive removal activity of some common organic and inorganic pollutants from water has been studied. To fully understand the adsorption process, the effects of initial dye concentration, pH of solution, adsorbent dosage, contact time and temperature on the adsorption process were successfully studied. Under the optimum conditions 10 wt% SA@HKUST-1 was able to reach the maximum adsorption capacity for Pb²⁺ (298 mg g⁻¹) and Malachite green (290 mg g⁻¹). Hopefully, this will facilitate research on improving the prospective use of MOFs for future applications.

Herein we introduce an effective approach for incorporating sulfamic acid (SA) into HKUST-1.

Synthesis of Novel Bis-pyrazole Derivatives as Antimicrobial Agents

BACKGROUND

Bis-heterocycles especially those containing pyrazole moiety display much better antibacterial activity than mono heterocycles.

OBJECTIVE

Herein, we synthesised a series of new bis-pyrazoles and investigated their antimicrobial agents.

METHODS

A novel series of bis-pyrazole derivatives have been synthesized in good yield by coupling reaction of cyanoacetic acid {4-[(2-cyano-acetyl)-hydrazonomethyl]-benzylidene}-hydrazide with a number of diazonium salts of aromatic amines in DMF in the presence of NaOH. Refluxing of the produced hydrazones with hydrazine-hydrate in ethanolic solution afforded the respective bis-pyrazoles. On the other hand, the reaction of bis(cyanoacetic acid hydrazide) derivative with a diversity of hydrazonoyl chlorides in dioxane under reflux gave bis-pyrazoles.

RESULTS

The structures of all the products were discussed and assured from all possible spectral data as well as for the elemental analysis. In addition, the results of the antimicrobial activity examination of selected derivatives revealed a high strength of some tested compounds compared to standard bactericides and fungicides utilized. Molecular docking of the newly synthesized compounds into the Enoyl ACP reductase active site supported the in vitro antimicrobial activity. All the tested compounds could fit in the enzyme binding pocket with significant binding affinities (-7.040 to -9.141 Kcal/mol).

CONCLUSION

The good results of the antimicrobial examination of the newly synthesized bis-pyrazoles comprise the considerable evidence of the importance of bis-heterocyclic compounds which encourages us to continue designing and synthesising a novel series with potent biological activity in the future.

Rational Design and Synthesis of Diverse Pyrimidine Molecules Bearing Sulfonamide Moiety as Novel ERK Inhibitors

Protein kinases orchestrate diverse cellular functions; however, their dysregulation is linked to metabolic dysfunctions, associated with many diseases, including cancer. Mitogen-Activated Protein (MAP) kinase is a notoriously oncogenic signaling pathway in human malignancies, where the extracellular signal-regulated kinases (ERK1/2) are focal serine/threonine kinases in the MAP kinase module with numerous cytosolic and nuclear mitogenic effector proteins. Subsequently, hampering the ERK kinase activity by small molecule inhibitors is a robust strategy to control the malignancies with aberrant MAP kinase signaling cascades. Consequently, new heterocyclic compounds, containing a sulfonamide moiety, were rationally designed, aided by the molecular docking of the starting reactant 1-(4-((4-methylpiperidin-1-yl)sulfonyl)phenyl)ethan-1-one (3) at the ATP binding pocket of the ERK kinase domain, which was relying on the molecular extension tactic. The identities of the synthesized compounds (4–33) were proven by their spectral data and elemental analysis. The target compounds exhibited pronounced anti-proliferative activities against the MCF-7, HepG-2, and HCT-116 cancerous cell lines with potencies reaching a 2.96 μM for the most active compound (22). Moreover, compounds 5, 9, 10b, 22, and 28 displayed a significant G2/M phase arrest and induction of the apoptosis, which was confirmed by the cell cycle analysis and the flow cytometry. Thus, the molecular extension of a small fragment bounded at the ERK kinase domain is a valid tactic for the rational synthesis of the ERK inhibitors to control various human malignancies.

Sustainable Synthetic Approach for (Pyrazol-4-ylidene)pyridines By Metal Catalyst-Free Aerobic C(sp2)-C(sp3) Coupling Reactions between 1-Amino-2-imino-pyridines and 1-Aryl-5-pyrazolones

A novel, metal catalyst-free, and efficient method has been developed for the synthesis of (pyrazol-4-ylidene)pyridine derivatives. The process involves dehydrogenative coupling of 1-amino-2-imino-pyridines with 1-aryl-5-pyrazolone derivatives utilizing O2 as the sole oxidant. The new method benefits from a high atom economy, efficiency, and substrate scope, as well as the simplicity of reaction and product purification procedures.

Synthesis, Characterization, Free-radical Scavenging Capacity and Antioxidant Activity of Novel Series of Hydrazone, 1,3,4-oxadiazole and 1,2,4- triazole Derived from 3,5-dimethyl-1H-pyrazole

Background:

Pyrazole is an important class of heterocyclic compound, has been shown to exhibit diverse biological and pharmacological activities such as anti-inflammatory, anti-cancer, antioxidant, etc.

Methods:

In this study, a series of novel 3,5-dimethyl-1H-pyrazole derivatives containing hydrazine 4a-l have been synthesized via the reaction of the 2-(3,5-dimethyl-1H-pyrazol-1-yl)acetohydrazide. All synthesized compounds have been tested for their in vitro antioxidant activities via utilization of 1,1-biphenyl-2-picrylhydrazyl (DPPH) as a free radical scavenging reagent.

Results:

The data reported herein indicates that compound 4k showed potential radical scavenging capacity and compounds 4f and 4g exhibited best activity for the iron binding while comparing with positive controls.

Conclusion:

Good activity was noted for some compounds. In particular, compound 4k showed the highest antioxidant activity with IC50 values of 22.79 ± 3.64 and 1.35 ± 0.66 μg/mL in the DPPH and ABTS tests, respectively.

Design and Amberlyst-15 mediated synthesis of novel thienyl-pyrazole carboxamides that potently inhibit Phospholipase A2 by binding to an allosteric site on the enzyme

Inflammation-mediated disorders are on the rise and hence, there is an urgent need for the design and synthesis of new anti-inflammatory drugs with higher affinity and specificity for their potential targets. The current study presents an effective and new protocol for the synthesis of thienyl-pyrazoles through 3 + 2 annulations using a recyclable heterogeneous catalyst Amberlyst-15. Chalcones 3(a-g) prepared from 3-methylthiophene-2-carbaldehyde and acetophenones by Claisen-Schmidt approach reacted with semicarbazide hydrochloride 4 in the presence of Amberlyst-15 in acetonitrile at room temperature producing thienyl-pyrazole carboxamides 5(a-h) in good yields. Alternatively, the compounds 5(a-h) were prepared by conventional method using acetic acid (30%) medium. Structures of synthesized new pyrazoles were confirmed by spectral and crystallographic studies. All the new compounds were evaluated for their in vitro inhibition of Phospholipase A2 from Vipera russelli and preliminary studies revealed that, amongst the designed series, compounds 5b, 5c and 5h showed promising inhibition. Further, the compounds exhibited linear mixed-type inhibition behavior for the sPLA2 enzyme indicating that they bind to an allosteric site distinct from either the calcium or substrate binding site on the enzyme. These kinetic conclusions were further validated by macromolecular rigid-body docking whereby compounds 5c and 5h showed binding to distinct pockets on the protein. These findings present a promising series of lead molecules that can serve as prototypes for the treatment of inflammatory related disorders.