Synthesis and biological activity of N,N-dialkylaminoalkyl-substituted bisindolyl and diphenyl pyrazolone derivatives

C(sp3)-H Carbonylative Cyclization of Hydrazones with CO2: Synthesis of Pyrazolone Derivatives

A novel method is reported to synthesize various pyrazolones through transition-metal-free and redox-neutral 1°, 2°, or 3° C(sp3)-H carbonylative cyclization using 1 atm of CO2 as a green carbonyl source, featuring good functional group tolerance, a broad substrate scope, facile scalability, and easy product transformation. The utility of this method could be demonstrated by the applications in preparing useful synthetic intermediates and bioactive compounds.

Role of hydrazone substituents in determining the nuclearity and antibacterial activity of Zn(II) complexes with pyrazolone-based hydrazones

Hydrazones and their metal derivatives are very important compounds in medicinal chemistry due to their reported variety of biological activities, such as antibacterial, antifungal and anticancer action. Five hydrazone-pyrazolone ligands...

Pd(ii)-Catalyzed regioselective functionalization of antipyrines: synthesis of pyrazolono-maleimides and pyrazolono-quinones

A Pd(ii)-catalyzed direct functionalization reaction of the 4Csp²-H bond of antipyrine derivatives is reported. This metal-catalyzed reaction of antipyrines with maleimides provided an easy and efficient access to biologically important pyrazolonomaleimides. This catalytic system is also applicable for C-4 functionalization of the antipyrine ring with quinone derivatives.

Investigation of antioxidant and anti-nociceptive potential of isoxazolone, pyrazolone derivatives, and their molecular docking studies

A series of new isoxazolone (3a-d) and pyrazolone (4a-d) derivatives were synthesized and assessed for their antioxidant and analgesic activity. Among synthesized compounds, 3b and 4b having nitro (NO₂ ) group show high analgesic activity at a dose of 6 mg/kg. Analgesic activity was further proceeded to explore the contribution of opioidergic mechanisms in the mediation of analgesic effects. Animals were administered with naloxone, a nonselective opioid inverse agonist, at the dose of 0.5 mg/kg. The results obtained suggested that the analgesic effects of the synthesized compounds were not reversed by naloxone, specifying that the compounds 3b and 4b do not follow the opioidergic pathway in order to relieve pain in animal models. Further, the binding interactions of compounds 3b and 4b were analyzed by docking them against nonopioid receptors COX-1 (3N8X) and COX-2 (3LN1). The results demonstrate the analgesic potential of isoxazolone and pyrazolone derivatives, especially compounds 3b and 4b can be considered promising lead molecules for further investigation and development into potent analgesic drugs. In addition, the antioxidant potential of compounds was also found to be related to better analgesic activity, thus providing an insight into the role of oxidative stress in the mediation of analgesia.

Pyrazolone structural motif in medicinal chemistry: Retrospect and prospect

The pyrazolone structural motif is a critical element of drugs aimed at different biological end-points. Medicinal chemistry researches have synthesized drug-like pyrazolone candidates with several medicinal features including antimicrobial, antitumor, CNS (central nervous system) effect, anti-inflammatory activities and so on. Meanwhile, SAR (Structure-Activity Relationship) investigations have drawn attentions among medicinal chemists, along with a plenty of analogues have been derived for multiple targets. In this review, we comprehensively summarize the biological activity and SAR for pyrazolone analogues, wishing to give an overall retrospect and prospect on the pyrazolone derivatives.

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The pyrazolone structural motif is a critical element of drugs aimed at different biological end-points.

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The pyrazolone analogues have been carried out to drug-like candidates with broad range of medicinal properties.

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This review wishes to give an overall retrospect and prospect on the pyrazolone derivatives.

Copper-catalyzed acylation of pyrazolones with aldehydes to afford 4-acylpyrazolones

Copper-catalyzed direct acylation of the alkenyl C-H bond in 1,2-dihydro-3H-pyrazol-3-ones has been developed, affording a series of 4-acylpyrazolones in moderate to good yields. Notably, this protocol involves readily accessible substrates and reagents, which have good functional group tolerance leading to pyrazolone derivatives under mild reaction conditions.

Efficient Preparation of Potassium Arylmethylene-4-(1H-Pyrazol-5-ol)-4′-(1H-Pyrazol-5-Olate) Derivatives via a Four-Component Reaction

A four-component reaction was investigated to prepare potassium arylmethylene-4-(1 H-pyrazol-5-ol)-4′-(1 H-pyrazol-5-olate) derivatives from dialkyl but-2-ynedioates, phenylhydrazine, substituted benzaldehydes and potassium carbonate without any catalyst or promoter. The structure of a typical product was confirmed by X-ray crystallography. The advantages of the present methodology are efficiency, broad scope, operational simplicity, high yields and mild reaction conditions.

Efficient pseudo five-component synthesis of 4,4′-(arylmethylene)-bis(3-methyl-1-phenyl-1H-pyrazol-5-ol) derivatives promoted by a novel ionic liquid catalyst

In this research, initial production and characterization of a novel Brønsted-acidic ionic liquid, namely, N,N,N′,N′-tetramethylethylenediaminium-N,N′-disulfonic acid hydrogen sulfate ([TMEDSA][HSO4]2), has been described (characterization was achieved using Fourier-transform infrared spectroscopy, 1H nuclear magnetic resonance (NMR), 13C NMR, and mass and thermal gravimetric spectra). Thereafter, utilization of [TMEDSA][HSO4]2 as a highly effectual catalyst for the synthesis of 4,4′-(arylmethylene)-bis(3-methyl-1-phenyl-1H-pyrazol-5-ol) derivatives through the one-pot pseudo five-component reaction of phenylhydrazine (2 eq.) with ethyl acetoacetate (2 eq.) and arylaldehydes (1 eq.) in relatively mild conditions, has been reported.

In vitro apoptosis-inducing effect and gene expression profiles of mixed ligand Cu(ii) complexes derived from 4-acyl pyrazolones on human lung cancer cells

Mixed-ligand Cu(ii) complexes of 4-acylpyrazolone ligands and poly pyridyls were synthesized, characterized and their anticancer activity was evaluated against A549 lung carcinoma cell lines.

4,5-Diaryl-3H-1,2-dithiole-3-thiones and related compounds as combretastatin A-4/oltipraz hybrids: Synthesis, molecular modelling and evaluation as antiproliferative agents and inhibitors of tubulin

A new series of 4,5-diaryl-3H-1,2-dithiole-3-thiones and related compounds were designed and synthesised as combretastatin A-4/oltipraz hybrids. We evaluated the antiproliferative activities, inhibition of tubulin polymerization, and cell-cycle effects of these compounds. Several compounds in this series, such as 4d and 5c, displayed significant activity against SGC-7901, KB and HT-1080 cell lines, as determined using MTT assays. The most active compound, 4d, markedly inhibited tubulin polymerization, with an IC50 value of 4.44 μM being observed. In mechanistic studies, 4d caused cell arrest in G2/M phase, induced apoptotic cell death, and disrupted microtubule formation. Molecular docking studies revealed that 4d interacts and binds efficiently with the tubulin protein.

Pyrazolone incorporating bipyridyl metallointercalators as effective DNA, protein and lung cancer targets: Synthesis, characterization and in vitro biocidal evaluation

Pyrazolone based metal complexes have strong bio-activity but the anti-cancer mechanism of these derivatives is not fully understood. In recent years, Cu(II) complexes have attracted the interest of researchers increasingly because of their high antitumor activities that are usually related to DNA binding. The reaction of three different derivatives (I) PPMP [3-methyl-1-phenyl-4-propionyl-1H-pyrazol-5(4H)-one], (II) TMCPMP [1-(3-chlorophenyl)-3-methyl-4-(4-methylbenzoyl)-1H-pyrazol-5(4H)-one] and (III) PPTPMP [3-methyl-4-propionyl-1-p-tolyl-1H-pyrazol-5(4H)-one] of 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one and 2.2' bipyridyl along with Cu(NO3)2·3H2O under methanolic condition allowed us to isolate and characterize a series of new mixed ligand complexes [Cu(TMCPMP) (Bipy)NCS] (1) [Cu(PPMP) (Bipy)NCS] (2) and [Cu(PPTPMP) (Bipy)NCS] (3). All complexes are well characterized by elemental analysis, metal estimation, molar conductivity, FT-IR and UV-Vis spectroscopy. The molecular geometry of these complexes has been determined by single crystal X-ray study. The single-crystal X-ray structures of complexes 1 and 2 exhibit square pyramidal geometry, while complex 3 revealed slightly distorted square-pyramidal geometry. The DNA binding of these compounds with Calf-Thymus DNA (CT-DNA) has been explored by emission titration methods, which revealed that 1-3 could interact with CT-DNA through intercalation mode. The complexes also exhibited a strong binding with Bovine Serum Albumin (BSA) over the ligands. Complexes were evaluated for their in vitro cytotoxic activities against lung cancer cell lines (A549) as well as noncancerous rat cardiomyocytes (H9C2) cell lines, which showed that all three complexes exhibited substantial cytotoxic activity with minimum effect on noncancerous cells. Complex 1 with more hydrophobic environment exhibited relatively high cytotoxic activity towards A549 cells. In summary, this new series of compounds belongs to a class of copper-pyrazolonate complexes that target many biochemical sites and with potential anti-cancer activity. All these results collectively suggested that complexes could serve as promising pharmacologically active substance against lung cancer.

Antibacterial, antifungal and in vitro antileukaemia activity of metal complexes with thiosemicarbazones

1-phenyl-3-methyl-4-benzoyl-5-pyrazolone 4-ethyl-thiosemicarbazone (HL) and its copper(II), vanadium(V) and nickel(II) complexes: [Cu(L)(Cl)]·C₂H₅OH·(1), [Cu(L)₂]·H₂O (2), [Cu(L)(Br)]·H₂O·CH₃OH (3), [Cu(L)(NO₃)]·2C₂H₅OH (4), [VO₂(L)]·2H₂O (5), [Ni(L)₂]·H₂O (6), were synthesized and characterized. The ligand has been characterized by elemental analyses, IR, ¹H NMR and ¹³C NMR spectroscopy. The tridentate nature of the ligand is evident from the IR spectra. The copper(II), vanadium(V) and nickel(II) complexes have been characterized by different physico-chemical techniques such as molar conductivity, magnetic susceptibility measurements and electronic, infrared and electron paramagnetic resonance spectral studies. The structures of the ligand and its copper(II) (2, 4), and vanadium(V) (5) complexes have been determined by single-crystal X-ray diffraction. The composition of the coordination polyhedron of the central atom in 2, 4 and 5 is different. The tetrahedral coordination geometry of Cu was found in complex 2 while in complex 4, it is square planar, in complex 5 the coordination polyhedron of the central ion is distorted square pyramid. The in vitro antibacterial activity of the complexes against Escherichia coli, Salmonella abony, Staphylococcus aureus, Bacillus cereus and the antifungal activity against Candida albicans strains was higher for the metal complexes than for free ligand. The effect of the free ligand and its metal complexes on the proliferation of HL-60 cells was tested.

A novel pyrazolone-based derivative induces apoptosis in human esophageal cells via reactive oxygen species (ROS) generation and caspase-dependent mitochondria-mediated pathway

Pyrazolone complexes have strong bio-activity but the anti-tumor mechanism of pyrazolone-based metal complexes is not fully understood. In this study, the inhibitory effect and possible mechanism of a novel pyrazolone-based derivative compound (Cd-PMPP-SAL) on human esophageal cancer cells were investigated. We found that Cd-PMPP-SAL inhibited the proliferation of Eca-109 cells in a dose-dependent manner and induced the apoptosis in the cells. Interestingly, Cd-PMPP-SAL promoted the production of ROS, loss of mitochondrial membrane potential, PARP cleavage and activation of caspase-3/9. These results suggest Cd-PMPP-SAL-induced apoptosis might be mediated by the increased production of ROS and caspase-dependent mitochondria-mediated pathway. These results suggest that Cd-PMPP-SAL is a potential candidate for the treatment of esophageal cancer.

Synthesis, Characterization, and Biological Activity of N (')-[(Z)-(3-Methyl-5-oxo-1-phenyl-1,5-dihydro-4H-pyrazol-4-ylidene)(phenyl)methyl]benzohydrazide and Its Co(II), Ni(II), and Cu(II) Complexes

Reaction of 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one and benzoyl hydrazide in refluxing ethanol gave N (')-[(Z)-(3-methyl-5-oxo-1-phenyl-1,5-dihydro-4H-pyrazol-4-ylidene)(phenyl)methyl]benzohydrazide (HL(1)), which was characterized by NMR spectroscopy and single-crystal X-ray structure study. X-ray diffraction analyses of the crystals revealed a nonplanar molecule, existing in the keto-amine form, with intermolecular hydrogen bonding forming a seven-membered ring system. The reaction of HL(1) with Co(II), Ni(II), and Cu(II) halides gave the corresponding complexes, which were characterized by elemental analysis, molar conductance, magnetic measurements, and infrared and electronic spectral studies. The compounds were screened for their in vitro cytotoxic activity against HL-60 human promyelocytic leukemia cells and antimicrobial activity against some bacteria and yeasts. Results showed that the compounds are potent against HL-60 cells with the IC50 value ≤5 μM, while some of the compounds were active against few studied Gram-positive bacteria.

An easy direct arylation of 5-pyrazolones

A mild, efficient and catalytic ligand-free method for the direct arylation of 5-pyrazolones by Pd-catalyzed C-H bond activation is reported. The process smoothly proceeds and yields are moderate to excellent.