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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. [ABSTRACT FROM AUTHOR]

The synthesis of previously unknown 4,5-dimethylfuro[3,4-d]pyridazin-1(2H)-one has been proposed and structurally characterized via a single-crystal X-ray diffraction analysis, 1H, 13C–{1H}, 1H–13C HMQC, and 1H–13C HMBC NMR spectroscopy, and IR spectroscopy. [ABSTRACT FROM AUTHOR]

From the point of view of the search for new pharmaceuticals, pyridazinone derivatives are a very promising group of compounds. In our previous works, we have proved that newly synthesized ligands from this group have desirable biological and pharmacokinetic properties. Therefore, we decided to continue the research evaluating the activity of pyrrolo[3,4-dpyridazinone derivatives. In this work, we focused on the interactions of five pyridazinone derivatives with the following biomolecules: DNA and two plasma proteins: orosomucoid and gamma globulin. Using several of spectroscopic methods, such as UV-Vis, CD, and fluorescence spectroscopy, we proved that the tested compounds form stable complexes with all biomacromolecules selected for analysis. These findings were also confirmed by the results obtained by molecular modeling. All tested pyridazinone derivatives bind to the ctDNA molecule via groove binding mechanisms. All these molecules can also be bound and transported by the tested plasma proteins; however, the stability of the complexes formed is lower than those formed with serum albumin. [ABSTRACT FROM AUTHOR]

26 derivatives of myricetin containing pyridazinone were designed and synthesized from the natural product myricitrin, which were structurally characterized by nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry (HRMS), and the structure of A14 was further determined using an X-ray single crystal diffractometer. The in vivo anti-tobacco mosaic virus (TMV) activity was tested by the half-leaf method, and the results showed that A4, A23 and A26 possessed better curative activity with effective concentration 50% (EC50) of 131.6, 138.5 and 118.9 μg mL−1, which were superior to that of ningnanmycin (NNM) (235.6 μg mL−1), respectively. A24 and A26 possessed better protective activity with EC50 values of 117.4 and 162.5 μg mL−1, superior to that of NNM (263.2 μg mL−1). Microcalorimetric thermophoresis (MST) and molecular docking assays showed that A23 and A26 had strong binding ability with TMV-CP. After treatment with A26, the chlorophyll content in tobacco was significantly higher than that in the control group, and the growth rate of malondialdehyde content was slowed down. This further confirmed that the drug molecules have good antiviral activity. [ABSTRACT FROM AUTHOR]

Multiple inhibitions of CA, COX-2 and 5-LOX enzymes has been recognised as a useful strategy for the development of anti-inflammatory drugs that can avoid the disadvantages of using NSAIDs alone. Here, we report new pyridazine-based sulphonamides (5a-c and 7a-f) as potential multi-target anti-inflammatory candidates. First, the furanone heterocycle in the dual CA/COX-2 inhibitor Polmacoxib was replaced with the pyridazinone one. Then, a hydrophobic tail was appended through benzylation of the 3-hydroxyl group of the pyridazinone scaffold to afford benzyloxy pyridazines 5a-c. Furthermore, the structures were adorned with the polar sulphonate functionality, in pyridazine sulphonates 7a-f, that are expected to be engaged in interactions with the hydrophilic half of the CA binding sites. All of the disclosed pyridazinones were tested for inhibitory activities against 4 hCA isoforms (I, II, IX, and XII), as well as against COX-1/2, and 5-LOX. Furthermore, in vivo anti-inflammatory and analgesic effects of pyridazinones 7a and 7b were examined. [ABSTRACT FROM AUTHOR]

This research aimed to discover novel isoniazid (INH) derivatives as anti-tubercular (anti-TB) agents. The chemical structures of isoniazid-based pyridazinone (IBP) derivatives were designed, and their toxicity and pharmacokinetic properties were predicted using the ProTox II and Swiss-ADME databases. The molecular docking of non-toxic IBPs was also performed concerning INH, pyrazinamide (PYZ), ethionamide (ETH), macozinone (MCZ), and BTZ043 utilizing DprE1 enzyme's proteins (PDB IDs: 4F4Q, 4NCR and 6HEZ). Based on the in silico study results, IBP19, IBP21, IBP22, and IBP29 were selected for their synthesis, and the spectral analysis confirmed their chemical structures. In vitro, anti-TB activity against Mtb H37Rv strain and MTT assay (against HepG2 and Vero cell lines) of IBP19, IBP21, IBP22, and IBP29 were also carried out. A total of eleven non-toxic IBPs were identified with promising pharmacokinetic parameters. The docking score (DS in kcal/mol against 6HEZ protein) of IBP19 (-9.52), IBP21 (-8.78), IBP22 (-9.07), and IBP29 (-9.99) was better than MCZ (-8.76) and BTZ043 (-8.56) revealing their DprE1 enzyme inhibitory action. The in vitro anti-TB activity evaluation (MIC values) confirmed that IBP19 (1.562 µg/ml), IBP21 (1.562 µg/ml), IBP22 (1.562 µg/mL), and IBP29 (1.562 µg/mL) had almost double potency than INH (3.125 µg/mL), and PYZ (3.125 µg/mL). IBP19, IBP21, IBP22, and IBP29 also displayed a CC50 value of > 300 µg/mL against HCL and VCL cell lines. This effect was better than INH (> 200 µg/mL), ETH (> 150 µg/mL), and PYZ (> 200 µg/mL). Accordingly, IBP19, IBP21, IBP22, and IBP29 provide a new template for developing safe and effective novel DprE1 inhibitors. [ABSTRACT FROM AUTHOR]

Isoxazolo[3,4-d] pyridazinones ([3,4-d]s) were previously shown to have selective positive modulation at the metabotropic glutamate receptor (mGluR) Subtypes 2 and 4, with no functional cross-reactivity at mGluR1a, mGluR5, or mGluR8. Additional analogs were prepared to access more of the allosteric pocket and achieve higher binding affinity, as suggested by homology modeling. Two different sets of analogs were generated. One uses the fully formed [3,4-d] with an N6-aryl with and without halogens. These underwent successful selective lateral metalation and electrophilic quenching (LM&EQ) at the C3 of the isoxazole. In a second set of analogs, a phenyl group was introduced at the C4 position of the [3,4-d] ring via a condensation of 4-phenylacetyl-3-ethoxcarbonyl-5-methyl isoxazole with the corresponding hydrazine to generate the 3,4-ds 2b and 2j to 2n. [ABSTRACT FROM AUTHOR]

The synthesis of previously unknown 4,5-dimethylfuro[3,4-d]pyridazin-1(2H)-one has been proposed and structurally characterized via a single-crystal X-ray diffraction analysis, 1H, 13C–{1H}, 1H–13C HMQC, and 1H–13C HMBC NMR spectroscopy, and IR spectroscopy.

A convenient approach to substituted pyrazoles and pyridazinones based on 1,2,4-triketones is presented. Chemo- and regiocontrol in condensations of t-Bu, Ph-, 2-thienyl-, and CO2Et-substituted 1,2,4-triketone analogs with hydrazines are described. The direction of preferential nucleophilic attack was shown to be switched depending on the substituent nature in triketone as well as the reaction conditions. The acid and temperature effects on the selectivity of condensations were revealed. Regiochemistry of heterocyclic core formation was confirmed by NMR and XRD studies. The facile construction of heterocyclic motifs bearing acetyl and (or) carbethoxy groups suggests them as promising mono- or bifunctional building blocks for subsequent transformations. [ABSTRACT FROM AUTHOR]

Secure and efficient treatment of diverse pain and inflammatory disorders is continually challenging. Although NSAIDs and other painkillers are well-known and commonly available, they are sometimes insufficient and can cause dangerous adverse effects. As yet reported, derivatives of pyrrolo[3,4-d]pyridazinone are potent COX-2 inhibitors with a COX-2/COX-1 selectivity index better than meloxicam. Considering that N-acylhydrazone (NAH) moiety is a privileged structure occurring in many promising drug candidates, we decided to introduce this pharmacophore into new series of pyrrolo[3,4-d]pyridazinone derivatives. The current paper presents the synthesis and in vitro, spectroscopic, and in silico studies evaluating the biological and physicochemical properties of NAH derivatives of pyrrolo[3,4-d]pyridazinone. Novel compounds 5a-c–7a-c were received with high purity and good yields and did not show cytotoxicity in the MTT assay. Their COX-1, COX-2, and 15-LOX inhibitory activities were estimated using enzymatic tests and molecular docking studies. The title N-acylhydrazones appeared to be promising dual COX/LOX inhibitors. Moreover, spectroscopic and computational methods revealed that new compounds form stable complexes with the most abundant plasma proteins–AAG and HSA, but do not destabilize their secondary structure. Additionally, predicted pharmacokinetic and drug-likeness properties of investigated molecules suggest their potentially good membrane permeability and satisfactory bioavailability. [ABSTRACT FROM AUTHOR]

Heterocyclics containing pyridazinone and piperazine structures are potential anticancer agents in the treatment of cancer disease caused by increasing the number of abnormal cells disrupting body biochemistry. There is a need for the design of more biocompatible drugs for the treatment of cancer with minimal side effects. For this purpose, a series of piperazinyl‐methyl‐3(2H)pyridazinone based compounds were synthesized and their anticancer activities were studied in vitro and in silico. The chemical structures of all the new compounds 3 (a–k) were identified by spectral analysis. The new compounds were screened in human lung and colon cancer cell lines to learn about their cytotoxic effects. The importance of the structure activity relationship was seen in this study and the compounds containing methoxy groups on the phenyl ring (3 a, 3 b, 3 e–3 g) were found to have higher cytotoxic effects than those without. It was determined that one of these compounds (3 a) demonstrated significant cytotoxic effect against both cell lines for 72 h as in vitro. The geometry of the synthesized 3 a ligand was optimized using the hybrid B3LYP functional density functional theory (DFT). Molecular docking study of 3 a compound was performed against EGFR (PDB ID : 1M17) and VEGFR‐2 (PDB ID: 2RL5) molecular targets. [ABSTRACT FROM AUTHOR]

Pyridazinones are important nitrogen‐rich heterocyclic core that has been driving the substantial medicinal interest due to their wide range of biological activities. This privileged scaffold forms a central core in numerous potent compounds, which results in the development of novel anticancer drugs with fruitful biological activities. The current review article summarizes the progressive development of novel pyridazinone derivatives that are targets for numerous receptors such as C‐met kinase inhibitors, PARP inhibitors, Tubulin polymerization inhibitors, Dihydro folate reductase inhibitors, B‐Raf inhibitors, Bruton tyrosine kinase inhibitors, FER tyrosine kinase inhibitors, and fibroblast growth factors receptors. It features the various simple techniques for the synthesis of pyridazinones and also highlights the mechanistic insights into the anticancer properties of pyridazinone derivatives. [ABSTRACT FROM AUTHOR]

N-containing chemicals are increasingly utilized as building blocks in the synthesis of medicines, pesticides, polymers, and other functional materials. However, efficiently accessing N-containing chemicals from biomass and their platform compounds remains a pivotal challenge. We here report the first biomass-based click reaction to synthesize a nitrogen-containing compound, 4,5-dihydro-6-methylpyridazin-3(2H)-one (DHMP), from biomass-derived levulinic acid (LA) and hydrazine hydrate. The reaction proceeded in water under a catalyst-free condition and achieved a quantitative product yield at room temperature in a few minutes, fulfilling the criteria of a click reaction. Furthermore, DHMP was selectively transformed into a range of bio-based N-containing chemicals, namely pyrrolidone, pyridazinone, and alkyl pyridazinone, through different catalytic approaches, demonstrating the feasibility of using DHMP as a N platform. The current work opens up a new realm in biomass utilization and also adds a new category to the current bio-based N-containing chemical families. [ABSTRACT FROM AUTHOR]

Some pyrazole-based heterocycles, such as pyrrolone, pyridazinone, and imidazole derivatives were synthesized utilizing the pyrazolyl-2(3H)-furanone derivative 3, which was obtained in a good yield via Perkin condensation of 5-chloro-4-formyl-3-methyl-1-phenylpyrazole with 3-(4-methylbenzoyl)propionic acid in the presence of cyclo-dehydrating agent (sodium acetate and acetic anhydride). Also, the acid hydrazide obtained was reacted with some carbonyl reagents like acetic anhydride, benzoyl chloride, 4-chlorobenzaldehyde, and 1,3-diphenyl-4-formylpyrazole, aiming to achieve new pyrrolone derivatives. The antioxidant activity screening of some synthesized compounds demonstrated that pyridazinone and N-phenylhydrazide derivatives showed the most exceptional potencies. [ABSTRACT FROM AUTHOR]

In this work, a novel series of pyridazinone derivatives (3–17) were synthesized and characterized by NMR (1H and 13C), FT-IR spectroscopies, and ESI-MS methods. All synthesized compounds were screened for their antibacterial activities against Staphylococcus aureus (Methicillin-resistant), Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa, and Acinetobacter baumannii. Among the series, compounds 7 and 13 were found to be active against S. aureus (MRSA), P. aeruginosa, and A. baumannii with the lowest MIC value range of 3.74–8.92 µM. Afterwards, DFT calculations of B3LYP/6-31++G(d,p) level were carried out to investigate geometry structures, frontier molecular orbital, molecular electrostatic potential maps, and gap energies of the synthesized compounds. In addition, the activities of these compounds against various bacterial proteins were compared with molecular-docking calculations. Finally, ADMET studies were performed to investigate the possibility of using of the target compounds as drugs. [ABSTRACT FROM AUTHOR]

Fatty acid binding protein (FABP4) inhibitors are of synthetic and therapeutic interest and ongoing clinical studies indicate that they may be a promise for the treatment of cancer, as well as other diseases. As part of a broader research effort to develop more effective FABP4 inhibitors, we sought to identify new structures through a two-step computing assisted molecular design based on the established scaffold of a co-crystallized ligand. Novel and potent FABP4 inhibitors have been developed using this approach and herein we report the synthesis, biological evaluation and molecular docking of the 4-amino and 4-ureido pyridazinone-based series. [ABSTRACT FROM AUTHOR]

The ribosome is a macromolecular machine that catalyzes the sequence-defined polymerization of L-α-amino acids into polypeptides. The catalysis of peptide bond formation between amino acid substrates is based on entropy trapping, wherein the adjacency of transfer RNA (tRNA)-coupled acyl bonds in the P-site and the α-amino groups in the A-site aligns the substrates for coupling. The plasticity of this catalytic mechanism has been observed in both remnants of the evolution of the genetic code and modern efforts to reprogram the genetic code (e.g., ribosomal incorporation of non-canonical amino acids, ribosomal ester formation). However, the limits of ribosome-mediated polymerization are underexplored. Here, rather than peptide bonds, we demonstrate ribosome-mediated polymerization of pyridazinone bonds via a cyclocondensation reaction between activated γ-keto and α-hydrazino ester monomers. In addition, we demonstrate the ribosome-catalyzed synthesis of peptide-hybrid oligomers composed of multiple sequence-defined alternating pyridazinone linkages. Our results highlight the plasticity of the ribosome's ancient bond-formation mechanism, expand the range of non-canonical polymeric backbones that can be synthesized by the ribosome, and open the door to new applications in synthetic biology. Ribosomes have evolved to polymerize L-α-amino acids into proteins comprising a peptide backbone. Here, a pyridazinone backbone is formed using ribosomes in vitro, producing a variety of sequence-defined alternating block-copolymers. [ABSTRACT FROM AUTHOR]

A series of novel (p‐chlorophenyl)‐3(2H)pyridazinone compounds were synthesized starting from p‐chloroacetophenone as AChE/BChE inhibitors. The chemical structures of all the compounds were identified by spectral analysis. Cholinesterase inhibition activity studies and in silico studies of compounds designed to eliminate the symptomatic effects of Alzheimer's disease and slow down neurodegeneration were evaluated. According to the results obtained, it was revealed that N‐substituted‐(p‐ chlorophenyl)pyridazin‐3(2H)‐one derivatives inhibited enzymes significantly. Ki values were found for acetylcholinesterase in the range of 10.2±4.0–20.9±7.6 nM and for butyrylcholinesterase in the range of 0.70±0.34–1.67±1.12 nM. Compound 5e showed the best effect on AChE activity compared to Tacrine. Also, compound 5b showed the best effect in BChE inhibition. The interactions of the synthesized compounds with the best experimental activities against AChE, BChE, respectively, were investigated by in silico approaches. In molecular docking, 5b compound with AChE crystal structure (PDB ID:1ACJ), binding site and binding parameters of 5e compound with BChE crystal structure were investigated in detail. The results indicated that compound 5b and 5e could be a promising lead compound for further development as a therapeutic agent for Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Transient receptor potential canonical 5 (TRPC5) is a calcium-permeable non-selective cation channel involved in various pathophysiological processes, including renal injury. Recently, GFB-887, an investigational pyridazinone TRPC5 inhibitor, demonstrated significant therapeutic potential in a Phase II clinical trial for focal segmental glomerulosclerosis (FSGS), a rare and severe form of chronic kidney disease (CKD). In the current study, based on the structure of GFB-887, we conducted extensive structural modification to explore novel TRPC5 inhibitors with desirable drug-like properties and robust nephroprotective efficacy. A series of pyridazinone derivatives featuring a novel tetrahydroimidazo[1,2- a ]pyrazine scaffold were synthesized and their activities were evaluated in HEK-293 cells stably expressing TRPC5 using a fluorescence-based Ca2+ mobilization assay. Among these compounds, compound 12 is turned out to be a potent TRPC5 inhibitor with apparent affinity comparable to the parent compound GBF-887. Compound 12 is highly selective on TRPC4/5 over TRPC3/6/7 and hERG channels, along with acceptable pharmacokinetic properties and a favorable safety profile. More importantly, in a rat model of hypertension-induced renal injury, oral administration of compound 12 (10 mg/kg, BID) efficaciously reduced mean blood pressure, inhibited proteinuria, and protected podocyte damage. These findings further confirmed the potential of TRPC5 inhibitors on the CKD treatment and provided compound 12 to be a valuable tool for exploring TRPC4/5 pathophysiology. [Display omitted] • Pyridazinone derivatives featuring tetrahydroimidazo[1,2- a ]pyrazine scaffold were synthesized as potent TRPC5 inhibitors. • Compound 12 selectively inhibited TRPC4/5 over TRPC3/6/7 and hERG channels. • Compound 12 displayed acceptable pharmacokinetic properties. • Compound 12 suppressed hypertension-induced proteinuria and podocyte injury in DOCA-salt rats. [ABSTRACT FROM AUTHOR]

The pharmacotherapy of inflammatory bowel disease (IBD) is still not fully effective and safe. Attempts to search for new IBD drugs remain an incessant research aim. One of the novel approaches is targeting the developmental pathway molecules and effector cytokines of Th17/Treg axis. This study aimed to elucidate the impact of new pyrrolo[3,4-d]pyridazinone derivatives, compounds 7b, 10b, or 13b, on the course of experimental colitis in rats and to assess whether these new compounds may influence Th17/Treg axis. Rats were pretreated with studied compounds intragastrically before intrarectal administration of 2,4,6-trinitrobenzenesulfonic acid used for colitis induction. Body weight loss, disease activity index, colon index, and colon tissue damage were analyzed to evaluate the severity of colitis. The colonic levels of RORγt, STAT3, CCR6, Foxp3, IL-6, IL-10, IL-17, TNF-α, IL-23, and PGE2 were assessed. Pretreatment with compounds 7b and 13b alleviated the severity of colitis and concomitantly counteracted the increased levels of RORγt, STAT3, CCR6, IL-6, IL-17, IL-23, TNF-α, and PGE2. The beneficial effect of compounds 7b and 13b may be due to the decrease in the levels of Th17-specific transcription factors and cytokines. The studied compounds might therefore constitute a promising therapeutic strategy in Th17/Treg imbalance-driven inflammatory conditions such as IBD. [ABSTRACT FROM AUTHOR]

In this study, a series of N‐substituted‐(p‐tolyl)pyridazin‐3(2H)‐one derivatives were synthesized and evaluated for their AChE inhibitory activity. The chemical structures of novel compounds 5(a–m) were confirmed by 1H‐NMR, 13C‐NMR, IR and HRMS analysis. In order to eliminate the symptomatic effects of Alzheimer's disease, the proposed compounds were evaluated by acetylcholinesterase inhibition activity study in accordance with the cholinergic hypothesis. The results revealed that the N‐substituted‐(p‐tolyl)pyridazin‐3(2H)‐one derivatives inhibited the enzymes significantly. Ki values for acetylcholinesterase in the range of 0.56±0.15–4.12±1.42 μM. Compound 5 h demonstrated the greatest in AChE activity compared with tacrine (0.56±0.15 μM). Molecular docking studies were performed for all compounds that compared tacrine in AChE activity in‐vitro. As a result of molecular docking studies (ΔGBind, docking score, XP Gscore, Glide energy, Glide emodel), 5 f, 5 g and 5 h compounds showed good inhibitory properties in the AChE active site as in silico. [ABSTRACT FROM AUTHOR]

Depression is a serious psychological disorder that affects a significant population. We investigated the antidepressant activities of four pyridazinone derivatives that contain the hydrazide moiety using the forced swimming test (FST). The compounds tested exhibited good antidepressant activity compared to duloxetine. The most promising compound was compound 2, which reduced the duration of immobility during FST. The toxic effects of the four compounds on the histomorphology of the liver and stomach tissue also was evaluated. [ABSTRACT FROM AUTHOR]

Sixteen compounds (TR1–TR16) were synthesized and evaluated for their inhibitory activities against monoamine oxidase A and B (MAOs). Most of the derivatives showed potent and highly selective MAO-B inhibition. Compound TR16 was the most potent inhibitor against MAO-B with an IC50 value of 0.17 μM, followed by TR2 (IC50 = 0.27 μM). TR2 and TR16 selectivity index (SI) values for MAO-B versus MAO-A were 84.96 and higher than 235.29, respectively. Compared to the basic structures, the para-chloro substituent in TR2 and TR16 increased the inhibitory activity of MAO-B. TR2 and TR16 were reversible MAO-B inhibitors that were competitive, with Ki values of 0.230 ± 0.004 and 0.149 ± 0.016 µM, respectively. The PAMPA method indicated that compounds TR2 and TR16 had the tendency to traverse the blood–brain barrier. Docking investigations revealed that lead compounds were beneficial for MAO-B inhibition via association with key as well as selective E84 or Y326 residues, but not for MAO-A inhibition via interaction primarily driven by hydrophobic contacts. In conclusion, TR2 and TR16 are therapeutic prospects for the management of multiple neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Persistent inflammation contributes to a number of diseases; therefore, control of the inflammatory response is an important therapeutic goal. In an effort to identify novel anti-inflammatory compounds, we screened a library of pyridazinones and structurally related derivatives that were used previously to identify N-formyl peptide receptor (FPR) agonists. Screening of the compounds for their ability to inhibit lipopolysaccharide (LPS)-induced nuclear factor κB (NF-κB) transcriptional activity in human THP1-Blue monocytic cells identified 48 compounds with anti-inflammatory activity. Interestingly, 34 compounds were FPR agonists, whereas 14 inhibitors of LPS-induced NF-κB activity were not FPR agonists, indicating that they inhibited different signaling pathways. Further analysis of the most potent inhibitors showed that they also inhibited LPS-induced production of interleukin 6 (IL-6) by human MonoMac-6 monocytic cells, again verifying their anti-inflammatory properties. Structure–activity relationship (SAR) classification models based on atom pair descriptors and physicochemical ADME parameters were developed to achieve better insight into the relationships between chemical structures of the compounds and their biological activities, and we found that there was little correlation between FPR agonist activity and inhibition of LPS-induced NF-κB activity. Indeed, Cmpd43, a well-known pyrazolone-based FPR agonist, as well as FPR1 and FPR2 peptide agonists had no effect on the LPS-induced NF-κB activity in THP1-Blue cells. Thus, some FPR agonists reported to have anti-inflammatory activity may actually mediate their effects through FPR-independent pathways, as it is suggested by our results with this series of compounds. This could explain how treatment with some agonists known to be inflammatory (i.e., FPR1 agonists) could result in anti-inflammatory effects. Further research is clearly needed to define the molecular targets of pyridazinones and structurally related compounds with anti-inflammatory activity and to define their relationships (if any) to FPR signaling events. [ABSTRACT FROM AUTHOR]

• Under the impact of ultrasonic irradiation in HFIP: THF solvent, pyridazinone, triazinone, and phthalimide-containing epoxides, CS 2 , and various primary/secondary amines reacted to synthesize the biologically important 2‑hydroxy dithiocarbamates in the current work. • DFT simulations are utilized in the computational study to optimize the structure and determine the interaction energies and HOMO-LUMO energy gap. • The hirshfeld surface analysis was used to evaluate the intermolecular interactions of compounds 4a and 4p within their crystal lattices. • Compounds 4a-4t docking experiments revealed that compounds 4a, 4e , and 4o may operate as potent anti-inflammatory drugs by inhibiting the cyclooxygenase-2 enzyme. • A molecular dynamic simulation study was also conducted for 100 ns to assess the stability of the most effective compound 4o. Under the influence of ultrasonic irradiation, pyridazinone, triazinone, or phthalimide containing 2‑hydroxy dithiocarbamates, a biologically relevant novel organo-sulfur compound, was synthesized. Detailed characterization, computational, and molecular docking studies are being investigated. Molecular interactions were studied using 3D Hirshfeld surfaces and corresponding 2D fingerprint plots. Theoretical (DFT) studies on the molecular structure, HOMO, LUMO, and quantum chemical descriptors were performed at the B3LYP/6–311++ G (d,p) level of theory. At the same time, the interaction energy was computed using the B3LYP/6–31G(d,p) level of theory. The FMO study revealed that molecules 4a and 4p in the gas phase have 3.545 eV and 3.263 eV HOMO-LUMO energy gaps, respectively, and they are hence kinetically stable. Quantum chemical calculations confirm the electrophilic character of compounds 4a and 4p , as the molecule is stable and highly electrophilic. The interactions of 2‑hydroxy dithiocarbamate derivatives (4a-4t) with the ligand-binding site of the target COX-2 (cyclooxygenase-2) enzyme were investigated using in-silico molecular docking experiments. Compared to the standard medicine celecoxib, the results showed that most synthesized derivatives had better glide scores and interaction. The docking study of all the synthesized compounds revealed that compounds 4a, 4e , and 4o interact well with the COX-2 enzyme as anti-inflammatory drugs. Molecular dynamic simulation was utilized to validate the docking study and explore the stable binding site and interaction of compound 4o , which is the most potent. The findings indicated that compound 4o exhibited better stability and interaction when compared to the reference drug. The ultrasound-assisted HFIP-induced synthesis of novel pyridazinone, triazinone, and phthalimide-containing biologically relevant synthesis of 2‑hydroxy dithiocarbamates, as well as their crystal structure, computational characteristics, and molecular docking study, is reported here. The docking investigation of all synthesized compounds demonstrated that compounds 4a, 4e , and 4o interact well with the COX-2 enzyme as anti-inflammatory drugs. [Display omitted] [ABSTRACT FROM AUTHOR]

Developing effective therapies and medicines to conquer nonalcoholic steatohepatitis (NASH) is of great significance for public health and is faced with a major challenge. The activation of the thyroid hormone receptor agonist THRβ could be regulated by target drugs that has brought huge potential to the treatment of NASH. In this work, pyridazinone compound YWS01125 was synthesized for the first time. In this study, an ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) method for YWS01125 determination was established, and the pharmacokinetics of YWS01125 was evaluated. The half-life values (t1/2)of three different doses of YWS01125 was 189.12 ± 95.27, 152.64 ± 37.98, and 181.95 ± 64.25 min, respectively, and the tissue distribution studies demonstrated that YWS01125 was quickly distributed to various tissues. With successful application in the pharmacokinetics study of YWS01125, the UPLC-MS/MS method has shown characteristics of high sensitivity, rapidity, and good selectivity.

[Display omitted] Employing pre-existing functionalized scaffolds to generate focused libraries exemplifies an expedited approach in terms of synthetic feasibility and efficiency. This strategic synthesis is particularly well-suited for scaffolds that are unattainable with DNA-compatible chemical tools. This manuscript utilizes pyridazinone as a paradigmatic scaffold to elucidate the synthetic workflow. Three functionalized pyridazinone reagents were obtained by conventional organic chemistries and then applied to prepare corresponding DNA-encoded libraries (DELs) by robust DNA-compatible reactions and abundant building blocks (BBs), ensuring both diversity and quality in the final libraries. The feasibility of these focused DELs were confirmed by subsequent affinity selection and off-DNA validation against the BRD4 target. [ABSTRACT FROM AUTHOR]

• Flame-retardant effect of pyridazinone on bio-based epoxy resin was detected. • Strong yet tough N-rich hollow vesicles were formed via "radical capturing" effect. • Potential for high value-added conversion from resin carbon to functional carbon. Aromatic nitrogen heterocyclic structure is a key building block of high-performance polymer materials and nitrogen-doped porous carbons, yet systematic studies on its flame-retardant effects and carbonization mechanisms in thermoset materials is still lacking. Here, a pyridazinone embedded bio-based epoxy resin (CSPZ-EP) cured by 4,4ʹ-methylenedianiline (DDM) was prepared. Benefiting from the rigid biphenyl-like pyridazinone structure and the high cross-linking density originated from the self-catalyzed transesterification, the cured CSPZ-EP/DDM can easily pass the UL-94 test with a V-0 rating suggesting excellent intrinsic flame retardancy. The cone calorimeter results further demonstrated that the peak heat release rate, the total heat release and flame growth rate of CSPZ-EP/DDM were significantly reduced by 84.4 %, 28.4 % and 90.5 %, respectively, compared with those of bisphenol A epoxy resin. The higher graphitization degree of the char residues and a large amount of non-flammable pyrolysis gas ejection synergistically prevented the further spread of fire. Strong yet tough nitrogen-rich char layer formed after thermal ablation together with the renewable features and the facile preparation route of CSPZ-EP/DDM make it a potential precursor for heteroatom porous carbons. [ABSTRACT FROM AUTHOR]

A practical and scalable synthetic method for the synthesis of new amides and pyridazinones was established starting from the readily accessible materials as arenes, cyclic anhydrides, and 2-aminobenzimidazole or phenylhydrazine. This synthetic method includes a scalable reaction using L-proline functionalized propyl modified nanomagnetic in aqueous media without using any other harmful organic reagents or inorganic as AlCl3. The synthetic method enables to synthesize new amides and pyridazinone derivatives in manufacturing scale, with low reaction steps and high purity. The catalyst could easily be separated from the reaction mixture by using an external magnetic field and it was reusable and green. [ABSTRACT FROM AUTHOR]

The large originator pharmaceutical companies need more and more new compounds for their molecule banks, because high throughput screening (HTS) is still a widely used method to find new hits in the course of the lead discovery. In the design and synthesis of a new compound library, important points are in focus nowadays: Lipinski’s rule of five (RO5); the high Fsp3 character; the use of bioisosteric heterocycles instead of aromatic rings. With said aim in mind, we have synthesized a small compound library of new spiro[cycloalkane-pyridazinones] with 36 members. The compounds with this new scaffold may be useful in various drug discovery projects.

Inflammation is associated with the development of several diseases comprising cancer and cardiovascular disease. Agents that suppress cyclooxygenase (COX) and lipoxygenase (LOX) enzymes, besides chemokines have been suggested to minimise inflammation. Here, a variety of novel heterocyclic and non-heterocyclic compounds were prepared from novel three furanone derivatives. The structures of all synthesised compounds were confirmed by elemental and spectral analysis including mass, IR, and 1H-NMR spectroscopy. Anti-inflammatory activities of these synthesised compounds were examined in vitro against COX enzymes, 15-LOX, and tumour necrosis factor-α (TNF-α), using inhibition screening assays. The majority of these derivatives showed significant to high activities, with three pyridazinone derivatives (5b, 8b, and 8c) being the most promising anti-inflammatory agents with dual COX-2/15-LOX inhibition activities along with high TNF-α inhibition activity. [ABSTRACT FROM AUTHOR]

Background and Purpose: Due to the risk of gastrointestinal damage and various tissue toxicity associated with non-steroidal anti-inflammatory drugs (NSAIDs) use, investigating new anti-inflammatory agents with efficacy comparable to that of NSAIDs but reduced toxicity is still a major challenge and a clinical need. Based on our previous study, new 1,3,4-oxadiazole derivatives of pyrrolo[3,4-d]pyridazinone, especially 6-butyl-3,5,7-trimethyl-1-[[4-[[4-(4-nitrophenyl)piperazin-1-yl]methyl]-5-thioxo-1,3,4-oxadiazol-2-yl]methoxy]pyrrolo[3,4-d]pyridazin-4-one and 6-butyl-1-[[4-[[4-(4-chlorophenyl)-4-hydroxy-1-piperidyl]methyl]-2-thioxo-1,3,4-oxadiazol-5-yl]methoxy]-3,5,7-trimethyl-pyrrolo[3,4-d]pyridazin-4-one (hereafter referred to as the compounds 10b and 13b , respectively) seem to be promising anti-inflammatory agents. This study aimed to elucidate the effects of these two new derivatives on the course of experimental rat inflammation, liver and kidney function, and gastric mucosa. Methods: The anti-inflammatory effect of compounds 10b and 13b was evaluated using the carrageenan-induced paw edema test in rats. The increase in paw volume (paw edema), prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α) and myeloperoxidase (MPO) levels, histological alterations, and inflammatory cell infiltration in paw tissue were determined. Serum alanine transaminase (ALT) and aspartate transaminase (AST) activities, serum urea and creatinine levels, as well as changes in gastric mucosa, were measured as indicators of hepatic, renal, and gastric toxicity. Results: Pretreatment with both novel derivatives at 10 mg/kg and 20 mg/kg doses reduced paw edema, counteracted the increased PGE2 and TNF-α levels, reduced the influx of inflammatory cells, and decreased histopathological alterations in paw tissue. Compound 13b at a dose of 20 mg/kg was more effective than indomethacin in reversing the increased TNF-α levels and reducing the influx of inflammatory cells. Only compound 13b at all studied doses (5, 10, or 20 mg/kg) counteracted the increased MPO level in paw tissue. Both compounds neither caused alterations in ALT, AST, urea, creatinine parameters nor gastric mucosal lesions. Conclusion: New compounds exert an anti-inflammatory effect, presumably via inhibiting inflammatory mediators release and inflammatory cell infiltration. Moreover, both possess a more favorable benefit–risk profile than indomethacin, especially compound 13b. [ABSTRACT FROM AUTHOR]

We report here in silico repurposing studies on 52 new pyridazinone-based small-molecules through inverse virtual screening (iVS) methodologies. These analogues were originally designed as formyl peptide receptor (FPR) ligands. As it is sometimes the case in drug discovery programmes, subsequent biological screening demonstrated the inefficacy of the molecules in binding FPRs, failing in the identification of new hits. Through a focussed drug-repurposing approach we have defined a variety of potential targets that are suitable to interact with this library of pyridazinone-based analogues. A two-step approach has been conducted for computational analysis. Specifically, the molecules were initially processed through a pharmacophore-based screening. Secondly, the resulting features of binding were investigated by docking studies and following molecular dynamic simulations, in order to univocally confirm “pyridazinone-based ligand-target protein” interactions. Our findings propose aspartate aminotransferase as the most favourable repurposed target for this small-molecule series, worth of additional medicinal chemistry investigations in the field.

[Display omitted] The "clip-cycle" synthesis of 2-pyridazinones containing enaminonitriles from thioesters with dicyanohydrazones is achieved through a AgOAc-promoted acylation-cyclization-tautomerization cascade reaction. Moreover, the obtained 2-pyridazinones are further transformed into biologically significant bicyclic-fused pyridazinones exhibiting intriguing fluorescence emission properties. Additionally, quantum chemical calculations were performed to provide a rational explanation for the observed photophysical characteristics. [ABSTRACT FROM AUTHOR]

Sixteen compounds (TR1–TR16) were synthesized and evaluated for their inhibitory activities against monoamine oxidase A and B (MAOs). Most of the derivatives showed potent and highly selective MAO-B inhibition. Compound TR16 was the most potent inhibitor against MAO-B with an IC50 value of 0.17 μM, followed by TR2 (IC50 = 0.27 μM). TR2 and TR16 selectivity index (SI) values for MAO-B versus MAO-A were 84.96 and higher than 235.29, respectively. Compared to the basic structures, the para-chloro substituent in TR2 and TR16 increased the inhibitory activity of MAO-B. TR2 and TR16 were reversible MAO-B inhibitors that were competitive, with Ki values of 0.230 ± 0.004 and 0.149 ± 0.016 µM, respectively. The PAMPA method indicated that compounds TR2 and TR16 had the tendency to traverse the blood–brain barrier. Docking investigations revealed that lead compounds were beneficial for MAO-B inhibition via association with key as well as selective E84 or Y326 residues, but not for MAO-A inhibition via interaction primarily driven by hydrophobic contacts. In conclusion, TR2 and TR16 are therapeutic prospects for the management of multiple neurodegenerative diseases.

The first regio‐, diastereo‐, and enantioselective direct Mannich reaction of β,γ,‐unsaturated ketones with benzoxazinone cyclic imines was enabled by Lewis acid/Brønsted base cooperative catalysis. The dinuclear zinc complex catalyzed the reaction of a broad range of β,γ‐unsaturated ketones to proceed at the α‐site exclusively, leading to corresponding adducts with two consecutive tertiary carbon stereocenters in diastereomeric ratios of up to >20:1 and enantioselectivities generally in the 90–99 % ee range. These products were used as general intermediates in the synthesis of multisubstituted cyclocanalines, tetrahydro pyridazinones, and 4H‐furo[2,3‐b][1,4]benzoxazine derivatives. [ABSTRACT FROM AUTHOR]

Fibroblast growth factor receptors (FGFRs) have emerged as promising targets for anticancer therapy. In this study, we synthesized and evaluated the biological activity of 66 pyrazolo[3,4- d ]pyridazinone derivatives. Kinase inhibition, cell proliferation, and whole blood stability assays were used to evaluate their activity on FGFR, allowing us to explore structure−activity relationships and thus to gain understanding of the structural requirements to modulate covalent inhibitors' selectivity and reactivity. Among them, compound 10h exhibited potent enzymatic activity against FGFR and remarkably inhibited proliferation of various cancer cells associated with FGFR dysregulation, and suppressed FGFR signaling pathway in cancer cells by the immunoblot analysis. Moreover, 10h displayed highly potent antitumor efficacy (TGI = 91.6%, at a dose of 50 mg/kg) in the FGFR1-amplified NCI-H1581 xenograft model. A series of pyrazolo[3,4- d ]pyridazinone derivatives were synthesized. Kinase inhibition, cell proliferation, and whole blood stability assays were performed, allowing us to explore structure−activity relationship and to gain understanding of the structural requirements to modulate covalent inhibitors' selectivity and reactivity. Compound 10h displayed highly potent antitumor efficacy in the NCI-H1581 xenograft model. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] An expedient access to novel 4-phosphonomethyl-containing 2,6-disubstituted 4,5-dihydropyridazin-3(2 H)-ones involves the reaction of β-phosphono γ'-keto ester intermediates with hydrazines. The construction of the pyridazinone ring allows the installation of various substituents at the positions 2 and 6 as well as a valuable 4-positioned phosphonomethyl fragment. [ABSTRACT FROM AUTHOR]

We report here in silico repurposing studies on 52 new pyridazinone-based small-molecules through inverse virtual screening (iVS) methodologies. These analogues were originally designed as formyl peptide receptor (FPR) ligands. As it is sometimes the case in drug discovery programmes, subsequent biological screening demonstrated the inefficacy of the molecules in binding FPRs, failing in the identification of new hits. Through a focussed drug-repurposing approach we have defined a variety of potential targets that are suitable to interact with this library of pyridazinone-based analogues. A two-step approach has been conducted for computational analysis. Specifically, the molecules were initially processed through a pharmacophore-based screening. Secondly, the resulting features of binding were investigated by docking studies and following molecular dynamic simulations, in order to univocally confirm "pyridazinone-based ligand-target protein" interactions. Our findings propose aspartate aminotransferase as the most favourable repurposed target for this small-molecule series, worth of additional medicinal chemistry investigations in the field. [ABSTRACT FROM AUTHOR]

A mild and highly efficient stereoselective reaction using silica supported bismuth(III) chloride (SiO2-BiCl3) has been successfully employed in the synthesis of 6-methyl-2-aryl-4, 5-dihydropyridazin-3(2H)-one derivatives (3a-o) with a variety of phenyl hydrazines (1a-o) bearing either electron withdrawing or donating functional groups and 4-pentynoic acid (2). The catalyzed reaction proceeded smoothly under room temperature in THF to give the corresponding 3a-o derivatives in good to excellent yields. The 3a-o derivatives have been characterized by IR, 1H NMR, 13C NMR, mass and elemental analysis. The use of this approach allowed us to rapidly screen a selection of conditions and quickly confirm the viability of preparing the target 3a-o derivatives in short reaction times. [ABSTRACT FROM AUTHOR]

Pyridazine derivatives represent one of the most active classes of compounds possessing a wide spectrum of biological activity. They are widely used in pharmaceuticals and agrochemicals. In view of these facts and in continuation of our interest in the chemistry of pyridazines, pyridazinones are six membered cyclic 1,2-diazine having carbonyl group at 3-position of ring system. They are widely used for industrial purposes and also exhibit a broad range of biological activities. This short review compiles examples of the most promising antibacterial activity. An overview on the antifungal activity is also described. [ABSTRACT FROM AUTHOR]

Pyridazine and pyridazinone are heterocycles that contain two adjacent nitrogen atoms and shown wide range of pharmacological activities such as antimicrobial, antidepressant anti-hypertensive, anticancer, antiplatelet, antiulcer, herbicidal, antifeedant and various other anticipated biological activities. Pyridazine ring are present in some commercially available drugs and agrochemicals. Pyridazine based systems have been shown to have numerous practical applications. [ABSTRACT FROM AUTHOR]

Pyridazinone is a unique template that is associated with several pharmacogical activities. A new class of pyridazinone derivatives containing cyclic/acyclic amine moiety was synthesized and evaluated for their in vitro cytotoxic activity against HEP3BPN 11 (liver), MDA 453 (breast) and HL60 (leukemia) cancer cells. Three derivatives 4a (76.78±0.7 against HEP3BPN 11), 4b (71.55±0.88 against HL60), and 4e (79.04±0.2 against HEP3BPN 11 & 73.09±01 against MDA 453) showed promising anticancer activity were further tested for their potential to inhibit the proangiogenic cytokines involved in tumor progression. Free radical scavenging activities of these compounds were demonstrated using 2,2-diphenyl-1-picryl hydrazine (DPPH), OH and superoxide anion radicals. [ABSTRACT FROM AUTHOR]