Pyridazine Derivatives Research Articles

Parkinson's Disease: Unravelling the Medicinal Perspectives and Recent Developments of Heterocyclic Monoamine Oxidase-B Inhibitors.

Parkinson's disease is a neurodegenerative condition characterized by slow movement (bradykinesia), tremors, and muscle stiffness. These symptoms occur due to the degeneration of dopamine- producing neurons in the substantia nigra region of the brain, leading to reduced dopamine levels. The development of Parkinson's Disease (PD) involves a combination of genetic and environmental factors. PD is associated with abnormal regulation of the monoamine oxidase (MAO) enzyme. Monoamine oxidase inhibitors (MAOIs) are an important class of drugs used to treat PD and other neurological disorders. In the early stages of PD, monotherapy with MAO-B inhibitors has been shown to be both safe and effective. These inhibitors are also commonly used as adjuncts in long-term disease management, as they can improve both motor and non-motor symptoms, reduce "OFF" periods, and potentially slow disease progression. However, current MAO-B inhibitors come with side effects like dizziness, nausea, vomiting, light-headedness, and fainting. Therefore, accelerating the development of new MAO-B inhibitors with fewer side effects is crucial. This review explores natural compounds that may inhibit monoamine oxidase B (MAO-B), focusing on key findings from the past seven years. It highlights the most effective heterocyclic compounds against MAO-B, including thiazolyl hydrazone, pyridoxine-resveratrol, pyridazine, isoxazole, oxadiazole, benzothiazole, benzoxazole, coumarin, caffeine, pyrazoline, piperazine, piperidine, pyrrolidine, and morpholine derivatives. The review covers in vitro, in silico, and in vivo data, along with the structure- activity relationship of these compounds. These findings offer valuable insights for the development of more effective MAO-B inhibitors and advancements in Parkinson's disease research.

Concise Synthesis of Tetra-substituted 1,6-Dihydropyridazine and Pyridazine derivatives

We have developed a novel one pot three steps process, including phosphine catalyzed Rauhut−Currier reaction of γ-alkyl allenoate, Diels-Alder reaction with di-tert-butyl azodicarboxylate and followed by deprotection of Boc group, to prepared tetra-substituted 1,6-dihydropyridazine in good yield. The 1,6-dihydropyridazine was easily converted to pyridazine derivatives via oxidative aromatization by DDQ.

Molecular Docking Studies of Synthesized Pyridazinone Scaffolds as Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs)

Pyridazinone derivatives, 6-aryl-pyridazinone (2a–f) and 2-(N-substituted)-6-aryl-pyridazinone (3a–h) derivatives were synthesized and assessed for cytotoxicity action using brine shrimp assessment method and in silico molecular studies. In silico molecular study of pyridazine derivatives used as NNRTIs and Doravirine is used as reference drug. The compounds were investigated for docking modes onto probable binding sites with HIV reverse transcriptase. The majority of these demonstrated favorable binding interactive connections with the active receptor domain. The majority of the compounds exhibited a remarkable docked binding affinity score when compared with the reference drugs. Among the synthesized pyridazine derivatives, compounds 3a and 3c–h exhibited a good docking score. For the designed compounds, in silico ADME assessment indicated the favorable physicochemical properties to be a suitable drug candidate. The synthesized compounds could serve as a novel alternative in designing safe and effective anti-HIV options with reverse transcriptase inhibitor potential. In the cytotoxicity study, all the compounds were evaluated at dose levels 10, and 20 (μg/mL), and potassium dichromate was used as a reference. Compounds 2c and 2e have shown potent lethality through LC50 2.23 and 3.20 μg respectively. Various compounds, including 2a, 2b, 2d, and 2f have demonstrated significant cytotoxicity. Their LC50 values are 7.58, 6.76, 8.91, and 4.46 μg, respectively. Additionally, compounds 3b and 3d exhibited potent lethality with LC50 values of 4.023 and 4.20 μg. Other compounds, namely 3g, 3f, 3c, 3h, 3a, and 3e, displayed noteworthy cytotoxicity ability13.91, 12.58, 11.91, 11.76, 10.58, 9.76, and 7.46 μg, respectively having LC50 values. This study supports the use of in silico molecular design and the brine shrimp bioassay as a suitable, reliable, and simple method for assessing the bioactivity of compounds. It provides further evidence for their use in medicine.

Pyridazine Derivatives as New Antidiabetic Agents: Synthesis, In‐Vitro α‐Amylase Inhibitory Activity, Molecular Docking and Molecular Dynamics Simulations Studies

AbstractThis study involved the synthesis, characterization, and assessment of fourteen pyridazine analogs (designated as 1–14) to investigate their efficacy in inhibiting the α‐amylase enzyme for potential diabetes treatment using an in vitro approach. Additionally, in silico molecular docking and molecular dynamic (MD) simulations were conducted to assess the inhibitory properties of these analogs. Physicochemical and pharmacokinetic properties of the fourteen pyridazine analogs were predicted using the DataWarrior tool. Results indicated that all tested compounds demonstrated significant α‐amylase inhibitory activity, with IC50 values ranging from 81.28±0.00 to 1623.54±2.67 μM compared to the standard drug acarbose (IC50=220.42±36.40 μM). Notably, compounds 8 and 12 exhibited the most potent α‐amylase inhibitory activity, with IC50 values of 81.28±0.00 μM and 200.60±34.65 μM, respectively. Molecular docking analysis revealed binding energies ranging from −7.53 to −5.77 kcal/mol and inhibition constants ranging from 3.00 to 58.96 μM, with compounds 9, 7, 8, 5, and 3 demonstrating the best binding energies. Subsequent MD simulation analyses indicated that all five compound formed stable complexes after 100 ns MD simulation. Consequently, these compounds hold promise as potential α‐amylase inhibitors pending successful clinical validation.

Green One-Pot Synthesis of Thiazole Scaffolds Catalyzed by Reusable NiFe2O4 Nanoparticles: In Silico Binding Affinity and In Vitro Anticancer Activity Studies.

A facile, green, one-pot multicomponent synthesis strategy was employed to fabricate novel thiazole scaffolds incorporating phthalazine, pyridazine, and pyrido-pyridazine derivatives (4a-4o). This synthetic route entailed the reaction of an α-halo carbonyl compound (1) with thiosemicarbazide (2) and various anhydrides (3a-3o), utilizing NiFe2O4 nanoparticles as a reusable catalyst in an ethanol:water (1:1) solvent system. The cytotoxicity of the synthesized compounds was meticulously assessed against three cancer cell lines, A375, HeLa, and MCF-7, employing IC50 values (μM) as the benchmark, and compared to the reference drug erlotinib. Compound 4n displayed remarkable efficacy against A375 (0.87 ± 0.31 μM), HeLa (1.38 ± 1.24 μM), and MCF-7 (1.13 ± 0.96 μM) cell lines, significantly surpassing erlotinib's IC50 values. Additionally, compounds 4k, 4l, 4m, and 4o demonstrated notable cytotoxicity across all tested cell lines, indicating their potential as effective anticancer agents. In silico docking studies against Hsp82 and Hsp90 proteins indicated that ligands 4k, 4m, 4c, 4j, 4o, and 4l had superior binding affinities compared to erlotinib. ADME analysis showed that compounds 4n, 4j, 4l, 4m, and 4o had favorable pharmacokinetic profiles, including nontoxicity, high human intestinal absorption, and low CYP inhibitory promiscuity. Structure-activity relationship analysis revealed that cyano and benzylidene substitutions significantly enhanced anticancer activity. Overall, the synthesized compounds, particularly 4n, demonstrated high efficacy, favorable binding interactions, and promising pharmacokinetic profiles, making them strong candidates for further development as anticancer agents.

A Promising Paradigm Shift in Cancer Treatment with FGFR Inhibitors.

FGFR have been demonstrated to perform a crucial role in biological processes but their overexpression has been perceived as the operator component in the occurrence and progression of different types of carcinoma. Out of all the interest around cancer, FGFR inhibitors have assembled pace over the past few years. Therefore, FGFR inhibitors are one of the main fundamental tools to reverse drug resistance, tumor growth, and angiogenesis. Currently, many FGFR inhibitors are under the development stage or have been developed. Due to great demand and hotspots, different pharmacophores were approached to access structurally diverse FGFR inhibitors. Here, we have selected to present several representative examples such as Naphthyl, Pyrimidine, Pyridazine, Indole, and Quinoline derivatives that illustrate the diversity and advances of FGFR inhibitors in medicinal chemistry. This review focuses on the SAR study of FGFR inhibitors last five years which will be a great future scope that influences the medicinal chemist to work towards more achievements in this area.

Pyridazine Derivatives: Molecular Docking, ADMET Prediction, and Synthesis for Antihypertensive Activity.

The drug discovery and development domain has witnessed remarkable advancements due to the integration of computational methods, particularly Computer-Aided Drug Design (CADD). Discovering and creating new drugs involves structural modifications to enhance their effectiveness and physical attributes. This frequently includes employing semisynthetic techniques to investigate structure-activity relationships thoroughly. Noticeable progress in molecular biology, computational chemistry, combinatorial chemistry, and highthroughput screening is steering transformative changes in the pharmaceutical industry. High blood pressure or hypertension, a significant health issue, elevates the chances of heart, kidney, and brain complications, among other health concerns. It's a leading cause of untimely mortality globally. Therefore, it is important to search for new antihypertensive compounds that have fewer side effects and higher therapeutic activity. Following molecular docking of the pyridazine derivatives, compounds were subjected to In-silico ADMET analysis. Subsequently, a low molecular weight compound was synthesized. Among the synthesized compounds characterization procedures include TLC, FT-IR, 1HNMR, and LC-MS techniques. Compound 8 exhibited the most favorable molecular docking results with alpha A1 and beta 1 adrenergic receptors. Compounds 3, 5, and 6 fulfilled the essential ADMET criteria. Subsequently, Compounds 3, 4, and 5 underwent additional synthesis and characterization procedures, including TLC, FT-IR, 1H-NMR, and LC-MS techniques. Similar behavior was observed in compounds 6, 8, 10, and 11, all violating Pfizer's 3/75 rules in terms of TPAS. Hydrazinolysis of these b-benzoyl propionic acids produced pyridazine, which was utilized in synthesizing pyridazine derivatives. TLC, FT-IR, 1HNMR, and LCMS have characterized the compounds.

Novel 3,6-Disubstituted Pyridazine Derivatives Targeting JNK1 Pathway: Scaffold Hopping and Hybridization-Based Design, Synthesis, Molecular Modeling, and In Vitro and In Vivo Anticancer Evaluation.

A series of novel 3,6-disubstituted pyridazine derivatives were designed, synthesized, and biologically evaluated as preclinical anticancer candidates. Compound 9e exhibited the highest growth inhibition against most of the NCI-60 cancer cell lines. The in vivo anticancer activity of 9e was subsequently investigated at two dose levels using the Ehrlich ascites carcinoma solid tumor animal model, where a reduction in the mean tumor volume allied with necrosis induction was reported without any signs of toxicity in the treated groups. Interestingly, compound 9e was capable of downregulating c-jun N-terminal kinase-1 (JNK1) gene expression and curbing the protein levels of its phosphorylated form, in parallel with a reduction in its downstream targets, namely, c-Jun and c-Fos in tumors, along with restoring p53 activity. Furthermore, molecular docking and dynamics simulations were carried out to predict the binding mode of 9e and prove its stability in the JNK1 binding pocket.

Development of novel antibiotics derived from pyridazine: Synthesis, spectroscopic characterization, in vitro antimicrobial activity and molecular docking studies

In light of the increasing antibiotic resistance, it is crucial to discover new antimicrobial medications. Pyridazines are frequently investigated in research for the development of new chemical entities with enhanced therapeutic properties. Their structure allows for significant flexibility in the attachment of various functional groups, which is essential for drug discovery.Our work focuses on synthesizing new pyridazine derivatives (7a, 7b, 7c and 7d) through coupling reactions with various amino esters. The structures of these compounds have been analyzed using spectroscopic measurements including 1H, 13C NMR, IR, and mass spectroscopy. The compounds showed positive effects against two bacterial strains: Escherichia coli: ATCC25922 and Staphylococcus aureus: CIP543154. Molecular docking results of the protein 7AZ5 indicated significant affinities with these molecules through hydrogen bonds. Compounds 7a and 7d demonstrated the highest binding energies and the best antimicrobial activity, suggesting their potential as a model for creating novel and potent antimicrobial compounds.

Pyridazine (1, 2-diazine): A Versatile Pharmacophore Known for its Utility in Biological Systems

: The present review describes the biological essence of pyridazine scaffold. Around 142 biologically potential pyridazine entities are gathered in a pile from documented literature. Some of them are commercially available drugs, few are naturally occurring pyridazine compounds, and a wide variety of compounds containing pyridazine moiety are biologically tested, and some are under clinical trials. Rather than collecting large quantities of data, an attempt is made to compile valuable entities. However, efforts have been made to compile the maximum literature in brief. The main motto of this review is to provide a combination of therapeutically active pyridazine containing compounds for further drug design, discovery, and development to contribute to future medicinal chemistry. Our approach is to bring the most biologically potent pyridazine derivatives to medicinal chemists, biologists, pharmacists, and organic chemists. The present work encompasses the literature from 2000-2022 from different and authentic sources. The work is divided according to the bioactive nature of pyridazine nucleus.

Emerging therapeutics: The imidazo[1,2-b]pyridazine scaffold as a novel drug candidate for eumycetoma, a neglected tropical disease

Mycetoma is a neglected invasive infection endemic in tropical and subtropical regions, presenting as a chronic subcutaneous inflammatory mass that can spread to deeper structures, leading to deformities, disabilities, and potentially mortality. The current treatment of eumycetoma, the fungal form of mycetoma, involves antifungal agents, such as itraconazole, combined with surgical intervention. However, this approach has limited success, with low cure rates and a high risk of recurrence. This study addresses to the urgent need for more effective therapeutics by designing and synthesising 47 diversely pharmacomodulated imidazo [1,2-b]pyridazine derivatives using a simple synthetic pathway with good yields and purity. Of these, 17 showed promising in vitro activity against Madurella mycetomatis, the prime causative agent of eumycetoma, with IC50 ≤ 5 μM and demonstrated significantly lower cytotoxicity compared to standard treatments in NIH-3T3 fibroblasts. Notably, compound 14d exhibited an excellent activity with an IC50 of 0.9 μM, in the same order then itraconazole (IC50 = 1.1 μM), and achieved a favourable selectivity index of 16 compared to 0.8 for itraconazole. These promising results warrant further research to evaluate the clinical potential of these novel compounds as safer, more effective treatments for eumycetoma, thus addressing a profound gap in current therapeutic strategies.

Synthesis, COX-2 inhibition, anti-inflammatory activity, molecular docking, and histopathological studies of new pyridazine derivatives

Five new pyridazine scaffolds were synthesized and assessed for their inhibitory potential against both cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) compared with indomethacin and celecoxib. The majority of the synthesized compounds demonstrated a definite preference for COX-2 over COX-1 inhibition. Compounds 4c and 6b exhibited enhanced potency towards COX-2 enzyme with IC50 values of 0.26 and 0.18 µM, respectively, compared to celecoxib with IC50 = 0.35 µM. The selectivity index (SI) of compound 6b was 6.33, more than that of indomethacin (SI = 0.50), indicating the most predominant COX-2 inhibitory activity. Consequently, the in vivo anti-inflammatory activity of compound 6b was comparable to that of indomethacin and celecoxib and no ulcerative effect was detected upon the oral administration of compound 6b, as indicated by the histopathological examination. Moreover, compound 6b decreased serum plasma PEG2 and IL-1β. To rationalize the selectivity and potency of COX-2 inhibition, a molecular docking study of compound 6b into the COX-2 active site was carried out. The COX-2 inhibition and selectivity of compound 6b can be attributed to its ability to enter the side pocket of the COX-2 enzyme and interact with the essential amino acid His90. Together, these findings suggested that compound 6b is a promising lead for the possible design of COX-2 inhibitors that could be employed as safe and effective anti-inflammatory drugs.

Recent Advances in Design and Development of Diazole and Diazine Based Fungicides (2014-2023).

With fungal diseases posing a major threat to agricultural production, the application of fungicides to control related diseases is often considered necessary to ensure the world's food supply. The search for new bioactive agents has long been a priority in crop protection due to the continuous development of resistance against currently used types of active compounds. Heterocyclic compounds are an inseparable part of the core structures of numerous lead compounds, these rings constitute pharmacophores of a significant number of fungicides developed over the past decade by agrochemists. Among heterocycles, nitrogen-based compounds play an essential role. To date, diazole (imidazole and pyrazole) and diazine (pyrimidine, pyridazine, and pyrazine) derivatives make up an important series of synthetic fungicides. In recent years, many reports have been published on the design, synthesis, and study of the fungicidal activity of these scaffolds, but there was a lack of a comprehensive classified review on nitrogen-containing scaffolds. Regarding this issue, here we have reviewed the published articles on the fungicidal activity of the diazole and diazine families. In current review, we have classified the molecules synthesized so far based on the size of the ring.

In Silico and In Vitro Alpha-amylase Activities of Previously Synthesized Pyridazine Derivatives

Diabetes mellitus is one of the fastest-growing metabolic disorders. Worldwide, one out of 10 people suffer from diabetes mellitus. In this manuscript, we establish the antidiabetic potential of previously synthesized pyridazine derivatives using in silico and in vitro experiments. Molecular docking studies of pyridazine derivatives with pullulanase Amy12, isomaltase, and alpha-amylase receptors revealed that Molecules 45, 46, and 29 showed good docking interaction scores. ADMET analysis of the top three docked pyridazine derivatives (45, 46, and 29) showed lesser solubility and poor distribution behavior. Molecules 45, 46, and 29 maintained drug-like properties with good oral bioavailability. Molecules 45 and 29 showed reproductive toxicity without any sign of mutagenicity, tumorigenicity, or other irritancy. Molecule 46 emerged as a nontoxic molecule in all aspects. In vitro alpha-amylase inhibition data of molecules 45, 46, 29, and acarbose showed IC50 values of 8.67, 8.46, 8.83, and 66.65 μg/mL, respectively. The antidiabetic activity of pyridazine derivatives is increased with the presence of phenothiazine coupled with a biphenyl group, indole with a biphenyl group, and phenothiazine with an ethylphenyl group. Establishing these pyridazine derivatives using in vivo experiments could be beneficial in managing diabetes.

Discovery of Novel Pyridazine Herbicides Targeting Phytoene Desaturase with Scaffold Hopping.

Phytoene desaturase (PDS) is a critical functional enzyme in blocking ζ-carotene biosynthesis and is one of the bleaching herbicide targets. At present, norflurazon (NRF) is the only commercial pyridazine herbicide targeting PDS. Therefore, developing new and diverse pyridazine herbicides targeting PDS is urgently required. In this study, diflufenican (BF) was used as the lead compound, and a scaffold-hopping strategy was employed to design and synthesize some pyridazine derivatives based on the action mode of BF and PDS. The preemergence herbicidal activity tests revealed that compound 6-chloro-N-(2,4-difluorophenyl)-3-(3-(trifluoromethyl)phenoxy)pyridazine-4-carboxamide (B1) with 2,4-diF substitution in the benzeneamino ring showed 100% inhibition rates against the roots and stems of Echinochloa crus-galli and Portulaca oleracea at 100 μg/mL, superior to the inhibition rates of BF. Meanwhile, compound B1 demonstrated excellent postemergence herbicidal activity against broadleaf weeds, which was similar to that of BF (inhibition rate of 100%) but superior to that of NRF. This indicated that 6-Cl in the pyridazine ring is the key group for postemergence herbicidal activity. In addition, compound B1 could induce downregulation of PDS gene expression, 15-cis-phytoene accumulation, and Y(II) deficiency and prevent photosynthesis. Therefore, B1 can be considered as a promising candidate for developing high-efficiency PDS inhibitors.

Pyridazine derivatives as effective anti-corrosion additives for carbon steel in 1 M HCl: Electrochemical, surface and theoretical studies

The study aimed to investigate the corrosion inhibition performance of two new pyridazine derivatives namely ((E)-2-(3-(4-(carboxymethoxy)-3-methoxystyryl)-5-(2-chlorobenzyl)-6-oxopyridazin-1(6H)-yl)acetic acid (CO6) and (E)-6-(4-hydroxy-3-methoxystyryl)pyridazin-3(2H)-one (CO39) for carbon steel (C.S) in 1M HCl by combining electrochemical techniques, surface analysis and theoretical studies. The electrochemical impedance spectroscopy (EIS) data indicated that the inhibitory efficiencies of CO6 and CO39 increased with increasing inhibitor concentration but decreased with increasing temperature, achieving 97.0 % and 95.3 %, respectively. The results of the potentiodynamic polarization (PDP) measurements show that the two pyridazine derivatives acted as mixed inhibitors. In addition, experimental studies have shown that CO6 and CO39 reduce corrosion rates by adsorbing on the steel surface following Langmuir adsorption isotherms. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) indicated that a protective layer had been developed on the surface of the carbon steel, which prevented corrosion from progressing. Quantum chemical computations and the molecular structures of the inhibitors were employed to investigate the mechanism of inhibition. The adsorption of the compounds investigated on C.S was validated by theoretical calculations including density functional theory (DFT) and molecular dynamics simulation (MDS).

Synthesis of bioactive heterocyclic compounds using camphor

The aim of the work was to synthesize novel heterocyclic compounds derived from camphor with antibacterial activity. The pyridazine, xanthene, pyranothiazole, pyridinothiazole, thiophene and pyrazole derivatives were produced from 4,11,11-trimethyl-9-phenyl-7-(2-phenylhydrazono)-3,4,5,6,7,9-hexahydro-1H-1,4-methanoxanthen-8(2H)-one (1). Thiophene derivatives 6a,b were produced according to the Gewald’s reaction for thiophene synthesis. On the other hand, pyranothiazol derivatives 8a,b were synthesized by the multicomponent reactions between xanthene derivative 5, benzaldehyde and ethylcyanoacetate or malononitrile in ethanol/triethylamine. Whereas, pyridinothiazole derivative 9 was produced in ethanol/ammonium acetate by the multicomponent reaction between xanthene derivative 5, benzaldehyde and malononitrile. The antibacterial activity of the synthesized compounds was evaluated against E. coli bacteria. All synthesized compounds showed moderate activity against E. coli bacteria. KEY WORDS: Anti-microbial, Camphor, Heterocyclic, Pyrazol-3(2H)-one, Thiazol-4(5H)-one, Thieno[3,2-d]thiazole, Xanthenes Bull. Chem. Soc. Ethiop. 2024, 38(4), 1069-1076. DOI: https://dx.doi.org/10.4314/bcse.v38i4.20

Pyridazine derivative as potent antihyperglycemic agent: Synthesis, crystal structure, α-amylase and α-glucosidase inhibition and computational studies

In this study, a pyridazine derivative (PDZ-1) was synthesized and characterized by using 13C NMR, 1H NMR, FT-IR, UV–Vis, HRMS-ESI and single-crystal X-ray diffraction analysis (XRD). Density functional theory methods at the B3LYP/6–311++G** level of theory predict very good correlations in the geometrical parameters and spectra when they are compared with the corresponding experimental ones. The presence of dimer explains the broad IR band due to CH···O interactions. The scaled force constants and the 75 vibration modes of PDZ-1 have been completely assigned using the scaled quantum mechanical force field (SQMFF) methodology. The deactivating character of Cl atom probably explains that the densities of pyridazine rings in both media are higher than that corresponding to chlorobenzyl, as revealed by AIM study while NBO calculations show that the derivative is most stable in gas phase than ethanol solution. Frontier orbital studies reveal that PDZ-1 is most reactive in ethanol than in the gas phase. The title compound showed a potent α-glucosidase and α-amylase inhibition compared to Acarbose (IC50 = 113.6 ± 1.17 µM, 124.5 ± 0.64 µM, respectively) with IC50 values of 17.32 ± 0.76 and 109.41± 0.87 µM, respectively. In addition, molecular docking studies were performed to determine the binding modes and energies between PDZ-1 and the target enzymes.

Pyridazine and pyridazinone derivatives: Synthesis and in vitro investigation of their anti-inflammatory potential in LPS-induced RAW264.7 macrophages.

New pyridazine and pyridazinone derivatives 3a-g, 4a-f, 6a, and 6b were designed and synthesized. Cell viability of all compounds was established based on the viability of lipopolysaccharide-induced RAW264.7 macrophage cells determined via the MTT assay. In vitro inhibition assays on human COX-1 and COX-2 enzymes were conducted to probe the newly synthesized compounds' anti-inflammatory activity. The half maximal inhibitory concentration values for the most active compounds, 3d, 3e, and 4e towards COX-2 were 0.425, 0.519, and 0.356 µM, respectively, in comparison with celecoxib. The newly synthesized compounds' ability to inhibit the production of certain proinflammatory cytokines, such as inducible nitric oxide synthase, tumor necrosis factor-α, interleukin-6, and prostaglandin-E2, was also estimated in lipopolysaccharide-induced macrophages (RAW264.7 cells). Compounds 3d and 3e were identified as the most potent cytokine production inhibitors. The results of molecular modeling studies suggested that these compounds were characterized by a reasonable binding affinity toward the active site of COX-2, when compared to a reference ligand. These results might be taken into consideration in further investigations into new anti-inflammatory agents.

New thiazol-pyridazine derivatives as antimicrobial and antiviral candidates: Synthesis, and application

In this manuscript, we are motivated to investigate the reaction site-selectivity for the hydrazo thiazole derivatives (6a–c) with different types of active methylene groups such as malononitrile, and ethyl cyanoacetate. Based on their structural investigations and spectrum data, the results of these reactions have been established to be iminopyridazines (7a–c) and 6-oxopyridazine derivatives (8a–c). We tested the ability of the newly synthesized pyridazine derivatives to inhibit the microbes and COVID-19 proteins. Human coronavirus 229E (HCoV-229E) was used to investigate the antiviral efficacy of prepared compounds. Green monkey kidney (Vero-E6) cell lines were used to investigate MTT and cytopathic effect (CPE). The new 6-oxopyridazine derivatives (8a–c) revealed significant inhibitory efficacy and were capable of inhibiting the human coronavirus 229E. Moreover, the antimicrobial result showed that compounds iminopyridazine (7c) followed by iminopyridazine (7a) followed by iminopyridazine (7b) exhibited excellent antimicrobial properties toward all utilized strains, usually greater than that of common reference drugs, with MIC values ranging from 13 to 21 ppm, from 9 to 14 ppm, and from 8 to 19 ppm whereas, the remaining substances appeared to be promising effective. Structure-activity relationship (SAR) revealed that pyridazine scaffolds containing NH group, as well as substituted electron withdrawal group (Cl) in para-position for benzene ring attributed to thiazole moiety have the best activity. The current study successfully illustrated the possible application of heterocyclic derivatives with pyridazie nucleus including thiazole ring as the main compound in the development of dual antiviral (COVID-19) and antibacterial pharmaceuticals in the future.