Synthesis, biological evaluation, and docking studies of novel heterocyclic diaryl compounds as selective COX-2 inhibitors

Discovery of a new pyrido[2,3-d]pyridazine-2,8-dione derivative as a potential anti-inflammatory agent through COX-1/COX-2 dual inhibition

In this paper, we present the design and synthesis of a novel series of pyrido[2,3-d]pyridazine-2,8-dione derivatives via the annulation of the 2-pyridone pattern. The synthesized derivatives were evaluated for in vivo anti-inflammatory activity using an ear edema model. Compound 7c, which showed a greater inhibition of ear edema (82%), was further tested for its in vitro COX-1/COX-2 inhibitory activity. Compound 7c showed similar inhibitory activities against COX-1 and COX-2 isoenzymes. The structural features that ensure the dual inhibition of COX-1 and COX-2 were elucidated using molecular docking studies. Overall, the ring closing of 2-pyridone pattern I transformed this highly selective COX-2 inhibitor into a dual COX inhibitor (7c), which could serve as a model for determining selectivity for COX-2.

Computational Design, Synthesis, and Bioevaluation of 2-(Pyrimidin-4-yl)oxazole-4-carboxamide Derivatives: Dual Inhibition of EGFRWT and EGFRT790M with ADMET Profiling

The ongoing research in cancer treatment underscores the significance of dual epidermal growth factor receptor (EGFR) kinase inhibitors targeting both mutant and wild-type variants. In this study, employing in silico fragment-based drug design (FBDD) and computational analysis, we have successfully developed a novel chemical series of 2-(pyrimidin-4-yl)oxazole-4-carboxamide (16a-j) derivatives designed as dual EGFR kinase inhibitors. A comparative in vitro anticancer profile of the newly synthesized compounds (16a-j) was tested against a panel of five human cancer cell lines like prostate cancer (PC3 & DU-145), lung cancer (A549), human liver cancer (HEPG2), and breast cancer (MDA-MB-468) by employing MTT method. In this experiment a well-known anticancer agent, Etoposide was used as positive control. Most of the derivatives demonstrated significant cytotoxicity, ranging from excellent to moderate levels. The IC50 values for the synthesized compounds observed between 0.10 ± 0.052 to 9.83 ± 5.96 µM, while the positive control exhibited a range of 1.97 ± 0.45 µM to 3.08 ± 0.135 µM. These results indicate that the synthesized compounds demonstrate higher cytotoxic potency in comparison to the reference compound. Furthermore, all these compounds underwent screening against normal Vero cell lines to assess their cytotoxicity. In each case, the observed cytotoxicity values (IC50) were higher than 22 µM, affirming the compounds selectivity for cancer cell lines. Among the compounds investigated, three compounds (16a, 16e, and 16i) exhibited notable cytotoxicity, while two compounds (16g and 16h) demonstrated exceptional cytotoxicity. The selectivity index of the tested compounds indicates a pronounced preference for targeting cancer cell lines over normal cells. Furthermore, all the compounds 16a-j underwent assessment for their EGFR kinase inhibitory activity against both EGFRWT and mutated EGFRT790M. The results unveiled the potential eligibility of this new series of compounds as effective EGFR inhibitors. Moreover, compound 16h underwent additional testing for cell cycle analysis, revealing its capability to arrest the cell cycle in the G2/M phase and induce apoptosis at the IC50 concentration.

A Computational Method for the Binding Mode Prediction of COX-1 and COX-2 Inhibitors: Analyzing the Union of Coxibs, Oxicams, Propionic and Acetic Acids

Among the biological targets extensively investigated to improve inflammation and chronic inflammatory conditions, cyclooxygenase enzymes (COXs) occupy a prominent position. The inhibition of these enzymes, essential for mitigating inflammatory processes, is chiefly achieved through Non-Steroidal Anti-Inflammatory Drugs (NSAIDs). In this work, we introduce a novel method-based on computational molecular docking-that could aid in the structure-based design of new compounds or the description of the anti-inflammatory activity of already-tested compounds. For this, we used eight crystal complexes (four COX-1 and COX-2 each), and each pair had a specific NSAID: Celecoxib, Meloxicam, Ibuprofen, and Indomethacin. This selection was based on the ligand selectivity towards COX-1 or COX-2 and their binding mode. An interaction profile of each NSAID was compiled to detect the residues that are key for their binding mode, highlighting the interaction made by the Me group. Furthermore, we rigorously validated our models based on structural accuracy (RMSD < 1) and (R2 > 70) using eight NSAIDs and thirteen compounds with IC50 values for each enzyme. Therefore, this model can be used for the binding mode prediction of small and structurally rigid compounds that work as COX inhibitors or the prediction of new compounds that are designed by means of a structure-based approach.

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

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

Vicinal Diaryl-Substituted Isoxazole and Pyrazole Derivatives with In Vitro Growth Inhibitory and In Vivo Antitumor Activity

The vicinal diaryl heterocyclic framework has been widely used for the development of compounds with significant bioactivities. In this study, a series of diaryl heterocycles were designed and synthesized based on an in-house diaryl isoxazole derivative (9), and most of the newly synthesized derivatives demonstrated moderate to good antiproliferative activities against a panel of hepatocellular carcinoma and breast cancer cells, exemplified with the diaryl isoxazole 11 and the diaryl pyrazole 85 with IC₅₀ values in the range of 0.7-9.5 μM. Treatments with both 11 and 85 induced apoptosis in these tumor cells, and they displayed antitumor activity in vivo in the Mahlavu hepatocellular carcinoma and the MDA-MB-231 breast cancer xenograft models, indicating that these compounds could be considered as leads for further development of antitumor agents. Important structural features of this compound class for the antitumor activity have also been proposed, which warrant further exploration to guide the design of new and more potent diaryl heterocycles.

Inhibitory potential of nitrogen, oxygen and sulfur containing heterocyclic scaffolds against acetylcholinesterase and butyrylcholinesterase

Heterocycles are the key structures in organic chemistry owing to their immense applications in the biological, chemical, and pharmaceutical fields. Heterocyclic compounds perform various noteworthy functions in nature, medication, innovation etc. Most frequently, pure nitrogen heterocycles or various positional combinations of nitrogen, oxygen, and sulfur atoms in five or six-membered rings can be found. Inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes is a popular strategy for the management of numerous mental diseases. In this context, cholinesterase inhibitors are utilized to relieve the symptoms of neurological illnesses like dementia and Alzheimer's disease (AD). The present review focuses on various heterocyclic scaffolds and their role in designing and developing new potential AChE and BChE inhibitors to treat AD. Moreover, a detailed structure-activity relationship (SAR) has been established for the future discovery of novel drugs for the treatment of AD. Most of the heterocyclic motifs have been used in the design of new potent cholinesterase inhibitors. In this regard, this review is an endeavor to summarize the biological and chemical studies over the past decade (2010-2022) describing the pursuit of new N, O and S containing heterocycles which can offer a rich supply of promising AChE and BChE inhibitory activities.

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.

Urease inhibitory kinetics, molecular docking, SAR and ADME studies of imine analogues

A series of synthesized imine derivatives (3a–m), including thio-semicarbazone, semicarbazone, thiazole and oxazole functional moieties, were examined for in vitro urease inhibition activity.

Semicarbazones, thiosemicarbazone, thiazole and oxazole analogues as monoamine oxidase inhibitors: Synthesis, characterization, biological evaluation, molecular docking, and kinetic studies

A series of semicarbazone, thiosemicarbazone, thiazole, and oxazole derivatives were designed, synthesized, and examined for monoamine oxidase inhibition using two isoforms, i.e., MAO-A and MAO-B. Among all the analogues, 3c and 3j possessed substantial activity against MAO-A with IC₅₀ values of 5.619 ± 1.04 µM and 0.5781 ± 0.1674 µM, respectively. Whereas 3d and 3j were active against monoamine oxidase B with the IC₅₀ values of 9.952 ± 1.831 µM and 3.5 ± 0.7 µM, respectively. Other derivatives active against MAO-B were 3c and 3g with the IC₅₀ values of 17.67 ± 5.6 µM and 37.18 ± 2.485 µM. Moreover, molecular docking studies were achieved for the most potent compound (3j) contrary to human MAO-A and MAO-B. Kinetic studies were also performed for the most potent analogue to evaluate its mode of interaction with MAO-A and MAO-B.

Discovery of New Pyrazolopyridine, Furopyridine, and Pyridine Derivatives as CDK2 Inhibitors: Design, Synthesis, Docking Studies, and Anti-Proliferative Activity

New pyridine, pyrazoloyridine, and furopyridine derivatives substituted with naphthyl and thienyl moieties were designed and synthesized starting from 6-(naphthalen-2-yl)-2-oxo-4-(thiophen-2-yl)-1,2-dihydropyridine-3-carbonitrile (1). The chloro, methoxy, cholroacetoxy, imidazolyl, azide, and arylamino derivatives were prepared to obtain the pyridine-⁻C² functionalized derivatives. The derived pyrazolpyridine-N-glycosides were synthesized via heterocyclization of the C²-thioxopyridine derivative followed by glycosylation using glucose and galactose. The furopyridine derivative 14 and the tricyclic pyrido[3′,2′:4,5]furo[3,2-d]pyrimidine 15 were prepared via heterocyclization of the ester derivative followed by a reaction with formamide. The newly synthesized compounds were evaluated for their ability to in vitro inhibit the CDK2 enzyme. In addition, the cytotoxicity of the compounds was tested against four different human cancer cell lines (HCT-116, MCF-7, HepG2, and A549). The CDK2/cyclin A2 enzyme inhibitory results revealed that pyridone 1, 2-chloro-6-(naphthalen-2-yl)-4-(thiophen-2-yl)nicotinonitrile (4), 6-(naphthalen-2-yl)-4-(thiophen-2-yl)-1H-pyrazolo[3,4-b]pyridin-3-amine (8), S-(3-cyano-6-(naphthaen-2-yl)-4-(thiophen-2-yl)pyridin-2-yl) 2-chloroethanethioate (11), and ethyl 3-amino-6-(naphthalen-2-yl)-4-(thiophen-2-yl)furo[2,3-b]pyridine-2-carboxylate (14) are among the most active inhibitors with IC₅₀ values of 0.57, 0.24, 0.65, 0.50, and 0.93 µM, respectively, compared to roscovitine (IC₅₀ 0.394 μM). Most compounds showed significant inhibition on different human cancer cell lines (HCT-116, MCF-7, HepG2, and A549) with IC₅₀ ranges of 31.3–49.0, 19.3–55.5, 22.7–44.8, and 36.8–70.7 μM, respectively compared to doxorubicin (IC₅₀ 40.0, 64.8, 24.7 and 58.1 µM, respectively). Furthermore, a molecular docking study suggests that most of the target compounds have a similar binding mode as a reference compound in the active site of the CDK2 enzyme. The structural requirements controlling the CDK2 inhibitory activity were determined through the generation of a statistically significant 2D-QSAR model.

Synthesis, biological evaluation and molecular modeling of benzofuran piperidine derivatives as Aβ antiaggregant

A series of benzofuran piperidine derivatives were designed, synthesized and evaluated as multifunctional Aβ antiaggregant to treat Alzheimer's disease (AD). In vitro results revealed that all of them are very good Aβ antiaggregants and some of the compounds are potent acetylcholinesterase (AChE) inhibitors with moderate antioxidant property. Selected compounds were also tested for neuroprotection activity, LDH release, ATP production and inhibitory activity to prevent Aβ peptides binding to the cell membrane. The different modifications introduced in the structure of our lead compound 3 (hAChE IC₅₀ = 61 μM and self induced Aβ _25-35 aggregation 45.45%), to increase its activity toward AD related targets. The most interesting multifunctional Aβ antiaggregants were compounds 3a, 3h and 3i, highlighting 3h as potent Aβ antiaggregant and good antiacetylholinesterase inhibitor (self induced Aβ _25-35 aggregation 57.71% and hAChE IC₅₀ = 21 μM), with good neuroprotective and antioxidant activity. In addition, these three most promising compounds prevent intracellular reactive oxygen species (ROS) formation and cell apoptosis induced by Aβ_25-35 peptides in SH-SY5Y cells. Molecular docking studies were also accomplished to understand the binding interaction of these compounds on Aβ monomer, Aβ fibril and AChE. Based on all data, compounds 3a, 3h and 3i were concluded as potent multifunctional Aβ antiaggregant, useful candidate for the treatment of AD.

Crystal structure and Hirshfeld surface analysis of 4-(4-chloro-phen-yl)-5-methyl-3-{4-[(2-methyl-phen-yl)meth-oxy]phen-yl}-1,2-oxazole

In the title compound, C24H20ClNO2, the mean planes of 4-chloro-phenyl, 2-methyl-phenyl and phenyl-ene rings make dihedral angles of 62.8 (2), 65.1 (3) and 15.1 (2)°, respectively, with the 5-methyl-1,2-oxazole ring. In the crystal, mol-ecules are linked by inter-molecular C-H⋯N, C-H⋯Cl, C-H⋯π contacts and π-π stacking inter-actions between the phenyl-ene groups. Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯H (48.7%), H⋯C/C⋯H (22.2%), Cl⋯H/H⋯Cl (8.8%), H⋯O/O⋯H (8.2%) and H⋯N/N⋯H (5.1%) inter-actions.

Synthesis, characterization and anti-inflammatory properties of karanjin (Pongamia pinnata seed) and its derivatives

Karanja (Pongamia pinnata) is a medicinal tree used in the Indian traditional ayurvedic system for treating several ailments. The seeds contain a unique furano-flavonoid karanjin, which has shown to possess many medicinal properties. Its usage at the clinical level is affected due to poor solubility and absorption. In the present investigation, molecular modifications of karanjin were attempted and evaluated their effect on anti-inflammatory activity. Firstly, Karanja ketone was obtained from karanjin by hydrolysis, and it was converted into karanja ketone oxime. The oxime undergoes Beckmann rearrangement and cyclized to yield furano benzoxazole (karanja oxazole). The new derivatives were purified with >95% purity (HPLC) and spectrally characterized (HR-MS, FTIR, and NMR). Among the test compounds, karanja ketone oxime exhibited higher antioxidant activity with an IC50 value of 360 µg/ml (DPPH). Soy lipoxygenase-1 (LOX-1) inhibitory activity of oxime was higher (IC50 = 65.4 µM) than other compounds. Fluorescence studies showed that oxime had higher quenching capacity with a Qmax of 76.3% and a binding constant of 0.9 × 105 M-1 for soy LOX-1. In-silico interaction studies showed that karanja ketone oxime had the least binding energy of -5.76 kcal/mol with LOX-1 by forming two hydrogen bonds with hydrophobic amino acids Leu 390 and Gly 392. The compounds were evaluated for their acute anti-inflammatory activity by the paw and ear edema in the rat model. Karanjin inhibits paw edema and ear edema by 34.13% and 51.13%, respectively, whereas the derivatives inhibited by 45-57 % and 70-76.8%. This study reports a rational approach to synthesize karanjin derivatives with considerable anti-inflammatory properties, both in-vitro and in-vivo.

Macrooxazoles A-D, New 2,5-Disubstituted Oxazole-4-Carboxylic Acid Derivatives from the Plant Pathogenic Fungus Phoma macrostoma

In our ongoing search for new bioactive fungal metabolites, four previously undescribed oxazole carboxylic acid derivatives (1–4) for which we proposed the trivial names macrooxazoles A–D together with two known tetramic acids (5–6) were isolated from the plant pathogenic fungus Phoma macrostoma. Their structures were elucidated based on high-resolution mass spectrometry (HR-MS) and nuclear magnetic resonance (NMR) spectroscopy. The hitherto unclear structure of macrocidin Z (6) was also confirmed by its first total synthesis. The isolated compounds were evaluated for their antimicrobial activities against a panel of bacteria and fungi. Cytotoxic and anti-biofilm activities of the isolates are also reported herein. The new compound 3 exhibited weak-to-moderate antimicrobial activity as well as the known macrocidins 5 and 6. Only the mixture of compounds 2 and 4 (ratio 1:2) showed weak cytotoxic activity against the tested cancer cell lines with an IC₅₀ of 23 µg/mL. Moreover, the new compounds 2 and 3, as well as the known compounds 5 and 6, interfered with the biofilm formation of Staphylococcus aureus, inhibiting 65%, 75%, 79%, and 76% of biofilm at 250 µg/mL, respectively. Compounds 5 and 6 also exhibited moderate activity against S. aureus preformed biofilm with the highest inhibition percentage of 75% and 73% at 250 µg/mL, respectively.

Synthesis and screening of (E)-3-(2-benzylidenehydrazinyl)-5,6-diphenyl-1,2,4-triazine analogs as novel dual inhibitors of α-amylase and α-glucosidase

(E)-3-(2-Benzylidenehydrazinyl)-5,6-diphenyl-1,2,4-triazines analogs 1-27 were synthesized by multi-step reaction scheme and subjected to in vitro inhibitory screening against α-amylase and α-glucosidase enzymes. Out of these twenty-seven synthetic analogs, ten compounds 14-17, 19, and 21-25 are structurally new. All compounds exhibited good to moderate inhibitory potential in terms of IC₅₀ values ranging (IC₅₀ = 13.02 ± 0.04-46.90 ± 0.05 µM) and (IC₅₀ = 13.09 ± 0.08-46.44 ± 0.24 µM) in comparison to standard acarbose (IC₅₀ = 12.94 ± 0.27 µM and 10.95 ± 0.08 µM), for α-amylase and α-glucosidase, respectively. Structure-activity relationship indicated that analogs with halogen substitution(s) were found more active as compared to compounds bearing other substituents. Kinetic studies on most active α-amylase and α-glucosidase inhibitors 5, 7, 9, 15, 24, and 27, suggested non-competitive and competitive types of inhibition mechanism for α-amylase and α-glucosidase, respectively. Molecular docking studies predicted the good protein-ligand interaction (PLI) profile with key interactions such as arene-arene, H-<, <-<, and <-H etc., against the corresponding targets.

Synthesis of novel 3,5,6-trisubstituted 2-pyridone derivatives and evaluation for their anti-inflammatory activity

The inflammatory response is the reaction of living tissue to an injury of a foreign nature, such as infection and irritants, and occurs as part of the body's natural defence response. Compounds capable of inhibiting cyclooxygenase (COX) enzymes, especially COX-2, have great potential as anti-inflammatory agents. Herein we present the regioselective synthesis of 49 novel compounds based on the 2-pyridone nucleus. The topical anti-inflammatory activity of seventeen compounds was evaluated in mice by croton oil (CO) induced ear edema assay. Most of the compounds exhibited a high level of in vivo anti-inflammatory activity, reducing ear edema and myeloperoxidase (MPO) activity. The most active compounds (2a and 7a) were inhibitors of COX enzymes. Compound 2a selectively inhibited the COX-2, while 7a was nonselective. Further, the compound 2a showed effective binding at the active site of COX-2 co-crystal by docking molecular study.

Rational approaches, design strategies, structure activity relationship and mechanistic insights for therapeutic coumarin hybrids

Hybrid molecules, furnished by combining two or more pharmacophores is an emerging concept in the field of medicinal chemistry and drug discovery that has attracted substantial traction in the past few years. Naturally occurring scaffolds such as coumarins display a wide spectrum of pharmacological activities including anticancer, antibiotic, antidiabetic and others, by acting on multiple targets. In this view, various coumarin-based hybrids possessing diverse medicinal attributes were synthesized in the last five years by conjugating coumarin moiety with other therapeutic pharmacophores. The current review summarizes the recent development (2014 and onwards) of these pharmacologically active coumarin hybrids and demonstrates rationale behind their design, structure-activity relationships (SAR) and mechanistic studies performed on these hybrid molecules. This review will be beneficial for medicinal chemist and chemical biologist, and in general to the drug discovery community and will facilitate the synthesis and development of novel, potent coumarin hybrid molecules serving as lead molecules for the treatment of complex disorders.

Kinase Inhibitors of Novel Pyridopyrimidinone Candidates: Synthesis and In Vitro Anticancer Properties

A new class of pyridopyrimidinone compounds containing different nitrogenous heterocycles were synthesized starting from the key precursor 2-hydrazinyl-5-phenyl-7-(pyridin-3-yl)pyrido[2,3-d]pyrimidin-4(3H)-one via condensation with series of aromatic aldehydes and cyclization using different reagents as ethyl acetoacetate, ethyl cyanoacetate, diethyl malonate, and ammonium isothiocyanate. The bioassay results showed compound 6 to be highly effective towards three human cancer cell lines (HepG2, PC-3, and HCT-116) in vitro with promising activity values (IC50: 0.5 μM) relative to the standard doxorubicin (IC50: 0.6 μM). Kinase inhibitory evaluation of compound 6 displays hopeful inhibitory action against BRAF V600E, EGFR, and PDGFRβ at100 μM. The molecular docking studies supported the initial kinase assay.

A comprehensive review on biological activities of oxazole derivatives

The utility of oxazole as intermediates for the synthesis of new chemical entities in medicinal chemistry have been increased in the past few years. Oxazole is an important heterocyclic nucleus having a wide spectrum of biological activities which drew the attention of researchers round the globe to synthesize various oxazole derivatives and screen them for their various biological activities. The present review article aims to review the work reported on therapeutic potentials of oxazole scaffolds which are valuable for medical applications during new millennium.

Synthesis and characterization of new 4-aryl-2-(2-oxopropoxy)-6-(2,5-dichlorothiophene)nicotinonitrile and their furo[2,3-b]pyridine derivatives: Assessment of antioxidant and biological activity

A new series of furo[2,3-b]pyridine derivatives bearing aryl substituents were synthesized in two steps, where, the cyano-(2H)-pyridones (1a-l) were converted to the corresponding nicotinonitriles (2a-l), followed by the Thorpe-Ziegler ring cyclization to the furo[2,3-b]pyridine derivatives (3a-l). All new compounds were characterized by 1D-NMR experiments (1H and 13C) and 2D-NMR experiments (COSY, HMBC and HSQC), as well as ESI-MS and HR-ESI-MS data. The new compounds were screened for their antioxidant activities by 2,2-diphenyl-1-picryl-hydrazylhydrate (DPPH) free radical assay. The highest radical scavenging effect was observed for nicotinonitriles 2d, 2h and 2l and furo[2,3-b]pyridines 3b, 3f and 3j by methanolic solvent at 4.0 mg/mL concentration. Remarkably, all nicotinonitriles and furo[2,3-b]pyridine exhibited a significant radical scavenging activity after 24 and 48 hours compared with 0.5 hour.

Design, synthesis and biological potential of heterocyclic benzoxazole scaffolds as promising antimicrobial and anticancer agents

Background

Benzoxazole is the most important class of heterocyclic compound in medicinal chemistry. It has been incorporated in many medicinal compounds making it a versatile heterocyclic compound that possess a wide spectrum of biological activities.

Results

The molecular structures of synthesized benzoxazole derivatives were confirmed by physicochemical and spectral means. The synthesized compounds were further evaluated for their in vitro biological potentials i.e. antimicrobial activity against selected microbial species using tube dilution method and antiproliferative activity against human colorectal carcinoma (HCT 116) cancer cell line by Sulforhodamine B assay.

Conclusion

In vitro antimicrobial results demonstrated that compounds 4, 5, 7 and 16 showed promising antimicrobial potential. The in vitro anticancer activity indicated that compounds 4 and 16 showed promising anticancer activity against human colorectal cancer cell line (HCT 116) when compared to standard drug and these compounds may serve as lead compound for further development of novel antimicrobial and anticancer agents.

Knoevenagel Condensation between C-glycoside and Active Methylene Compounds without Catalysts

A Knoevenagel condensation reaction between a C-glycoside based aromatic aldehyde and cyclic active methylene compounds such as barbituric acid, thiobarbituric acid, 1,3-dimethylbarbituric acid, 5,5-dimethyl-1,3-cyclohexanedione, 2,2-dimethyl-1,3-dioxane-4,6-dione and 3-methyl-1-phenyl-2-pyrazolin-5-one has been developed, to give a series of unusual fused heterocyclic compounds. The structures of all the new compounds were established by the spectral data. This method which did not use any catalysts, has the advantages of operational simplicity and minimal environmental impact.

Molecular basis for nonspecificity of nonsteroidal anti-inflammatory drugs (NSAIDs)

Inhibition of the production of inflammatory mediators by the action of nonsteroidal anti-inflammatory drugs (NSAIDs) is highly accredited to their recognition of cyclooxygenase enzymes. Along with inflammation relief, however, NSAIDs also cause adverse effects. Although NSAIDs strongly inhibit enzymes of the prostaglandin synthesis pathways, several other proteins also serve as fairly potent targets for these drugs. Based on their recognition pattern, these receptors are categorised as enzymes modifying NSAIDs, noncatalytic proteins binding to NSAIDs and enzymes with catalytic functions that are inhibited by NSAIDs. The extensive binding of NSAIDs is responsible for their limited in vivo efficacy as well as the large spectrum of their effects. The biochemical nature of drugs binding to multiple protein targets and its implications on physiology are discussed.

Facile and expedient access to bis-coumarin–iminothiazole hybrids by molecular hybridization approach: synthesis, molecular modelling and assessment of alkaline phosphatase inhibition, anticancer and antileishmanial potential

A series of new cytotoxic bis-coumarin–iminothiazole hybrids was developed as potential inhibitors of alkaline phosphatase and leishmaniasis.

Crystal structure and DFT calculations of 5-(4-Chlorophenyl)-1-(6-methoxypyridazin-3-yl)-1H-pyrazole-3-carboxylic acid

The title compound, 5-(4-Chlorophenyl)-1-(6-methoxypyridazin-3-yl)-1H-pyrazole-3-carboxylic acid, has been characterized by using elemental analysis, MS, FT-IR, 1H NMR and 13C NMR spectroscopic, and crystallographic techniques. The title compound crystallizes in the triclinic space group P-1 with a=9.612(1), b=9.894(1), c=17.380(1)Å, α=90.213(5)°, β=104.99(1)°, γ=111.072(5)°, V=1481.3(2)Å3 and Dx=1.483 g cm(-3) respectively. The structure of the compound has also been examined by using quantum chemical methods. The molecular geometry and vibrational frequencies of monomeric and dimeric form of the title compound in the ground state have been calculated by using the B3LYP/6-31G(d,p) level of the theory. The calculated results show that the optimized geometry and the theoretical vibration frequencies of the dimeric form are good agreement with experimental data. In addition, HOMO-LUMO energy gap, molecular electrostatic potential map, thermodynamic properties of the title compound were performed at B3LYP/6-31G(d,p) level of theory.