A novel pyrazolone, 4,4-dichloro-1-(2,4-dichlorophenyl)-3-methyl-5-pyrazolone, as a potent catalytic inhibitor of human telomerase

Electrochemical oxidative selective halogenation of pyrazolones for the synthesis of 4-halopyrazolones

An efficient and environmentally friendly electrochemical oxidative selective halogenation of pyrazolones has been developed under conditions free of metals, external oxidants, and external supporting electrolytes. The reaction demonstrates good functional group tolerance and maintains high efficiency in large-scale synthesis, yielding moderate to excellent yields of the desired 4-halopyrazolones. This method provides a green and convenient route for the direct installation of a halogen moiety into bioactive pyrazolone derivatives, which can be utilized in a myriad of applications.

A copper-catalyzed asymmetric Friedel-Crafts hydroxyalkylation of pyrazole-4,5-diones with 5-aminoisoxazoles

An asymmetric Friedel-Crafts hydroxyalkylation reaction of 5-aminoisoxazoles with pyrazole-4,5-diones was developed under the catalysis of 5% chiral copper complexes. This reaction exhibits functional group tolerance and excellent enantioselectivity. Moreover, the reaction can be scaled up and its mechanism was studied.

Novel complex compounds of nickel with 3-(1-phenyl-2,3-dimethyl-pyrazolone-5)azopentadione-2,4: synthesis, NBO analysis, reactivity descriptors and in silico and in vitro anti-cancer and bioactivity studies

A synthesized azo compound based on 4-amino antipyrine and its complexes with Ni(II) in solution and solid phase is reported. The structures of these compounds have been testified by IR and NMR spectroscopy. The combined experimental and theoretical approach was used. To study the structure and properties of the synthesized compound, as well as its possible complex formation with the Ni(II), ab initio quantum-chemical calculations were carried out using the Hartree-Fock (HF) method with the 6-31 G basis set and the electron density functional theory (DFT) method with hybrid three-parameter potential B3LYP and extended basis set 6-311++G(d,p) taking into account polarization and diffuse functions for all atoms. The geometric, energy, and electronic parameters were calculated and analyzed. The HOMO-LUMO energy gap has been calculated to determine chemical activity. Both complexes had effective inhibition against butyrylcholinesterase and acetylcholinesterase. IC50 values were found as 19.43 and 27.08 µM for AChE, 2.37 and 7.40 µM for BChE, respectively. For the anticancer outcome, high doses of compound E1 inhibited viability by about 40-45%, while this rate was around 65-70% for compound E2 at the same doses. Anticholinesterase and anticancer potential of compounds E1 and E2 also evaluated by in silico techniques. Both compounds show strong binding to VEGFR1, with E2 exhibiting superior inhibitory activity in hAChE and hBChE through shorter and stronger interactions. MD simulations suggest that E2 forms more stable complexes with hAChE and hBChE compared to E1, making it a promising candidate for further exploration in anticancer and anticholinesterase therapies.Communicated by Ramaswamy H. Sarma.

Construction of a Chiral β-Fluoroamine by Asymmetric Mannich Reaction of 2-Fluoroindanone with Pyrazolinone Ketimines

The asymmetric Mannich reaction of 2-fluoroindanone with ketimine was developed under the catalysis of a kind of chiral copper complex, affording a chiral tetrahedral center containing fluorine. A series of β-fluoroamine derivatives can be obtained in excellent yields (73-94%) with high diastereoselectivities (>99:1 dr) and enantioselectivities (89-99%). The possible transition state was supported by density functional theory calculation.

Synthesis, structure elucidation, Hirshfeld surface analysis, DFT, and molecular docking of new 6-bromo-imidazo[4,5-b]pyridine derivatives as potential tyrosyl-tRNA synthetase inhibitors

Novel 6-bromo-imidazo[4,5-b]pyridine derivatives (2-4, 5a-13a, and 6b, 8b-13b) have been synthesized based on a developed systematic approach involving the condensation of 5-Bromo-2,3-diaminopyridine with a suitable aromatic aldehyde in the presence of molecular iodine in water, followed by alkylation reactions using different alkyl dibromide agents. The synthesized compounds were characterized by the NMR spectroscopy technique. The structures of 8a, 9a, 12a, and 11b were confirmed using monocrystalline X-ray crystallography. Theoretical calculations have been carried out using DFT and TD-DFT methods at the B3LYP/6-31G++(d,p) level of theory. Intermolecular contacts between units of 8a, 9a, 12a, and 11b were determined through the Hirshfeld surface analysis. The molecular docking study has been performed to determine the binding affinity of 8a, 9a, 12a, and 11b into the binding site of S. aureus tyrosyl-tRNA synthetase as a target enzyme, and the results revealed that 9a is the most potent compound among the selected compounds with a binding affinity of -8.74 Kcal/mol.Communicated by Ramaswamy H. Sarma.

Pyrazolone-type compounds (part II): in vitro and in silico evaluation of antioxidant potential; structure-activity relationship

The pyrazolone class comprises a variety of hybrid compounds displaying diverse biological actions. Although studied for decades, these compounds are still of interest due to their facile chemical transformations. In our previous work, we presented the synthetic route of functionalised pyrazolone derivatives. The presence of pyrazolone structural motif in many drugs, such as edaravone, prompted us to investigate the antioxidant features of the selected compounds. In this paper, we provide an extensive in vitro and in silico description of the antioxidant properties of selected pyrazolone analogues. The obtained in vitro results revealed their great antiradical potency against the DPPH radical (IC50 values in the 2.6-7.8 μM range), where the best results were obtained for analogues bearing a catechol moiety. Density functional theory (DFT) was used to assess their antioxidant capacity from the thermodynamic aspect. Here, good agreement with in vitro results was achieved. DFT was employed for the prediction of the most preferable radical scavenging pathway, also. In polar solvents, the SPLET mechanism is a favourable scavenging route, whereas in nonpolar solvents the HAT is slightly predominant. Furthermore, antioxidant mechanisms were studied in the presence of relevant reactive oxygen species. The obtained values of the reaction enthalpies with the selected radicals revealed that HAT is slightly prevailing in polar solvents, while the SPLET mechanism is dominant in nonpolar solvents. Regarding the well-known antioxidant features of the drug edaravone, these findings represent valuable data for this pyrazolone class and could be used as the basis for further investigations.

Catalytic asymmetric Michael/cyclization reaction of 3-isothiocyanato thiobutyrolactone: an approach to the construction of a library of bispiro[pyrazolone-thiobutyrolactone] skeletons

Here, we demonstrate the first example of 3-isothiocyanato thiobutyrolactone serving as a useful building block in the Michael/cyclization reaction with alkylidene pyrazolones for the enantioselective construction of optically active structural bispiro[pyrazolone-thiobutyrolactone] skeletons containing three contiguous stereocenters with two spiroquaternary stereocenters. These products were smoothly afforded in up to 90% yield, >20 : 1 dr and >99% ee with chiral squaramide as the catalyst under mild conditions. Notably, this is also the first example of the merger of a spirocyclic pyrazolone scaffold with a spirocyclic thiobutyrolactone scaffold, potentially useful in medicinal chemistry.

4-Nitropyrazolin-5-ones as Readily Available Fungicides of the Novel Structural Type for Crop Protection: Atom-Efficient Scalable Synthesis and Key Structural Features Responsible for Activity

The development of new types of fungicides for agriculture and medicine is highly desirable due to the uprising fungal resistance against commonly used compounds. Herein, 4-substituted-4-nitropyrazolin-5-ones (nitropyrazolones) were proposed as highly active fungicides of the novel structural type. The first scalable and practical method for the nitropyrazolone synthesis was proposed, which is atom-efficient, is applicable for the multigram scale synthesis, and allows for production of a wide variety of nitropyrazolones with high yields and purity. The synthesized compounds demonstrated high fungicidal activity against the broad spectrum of phytopathogenic fungi (Venturia inaequalis, Rhizoctonia solani, Fusarium oxysporum, Fusarium moniliforme, Bipolaris sorokiniana, and Sclerotinia sclerotiorum). Their mycelium growth inhibiting activity was comparable or superior to that of kresoxim-methyl. In vitro activity against Staphyloccocus aureus, Candida albicans, and Aspergillus niger revealed that nitropyrazolones are promising candidates against human pathogens. The key factors for the manifestation of high fungicidal activity were established to be an aromatic substituent on the N1 atom and small substituents, such as methyl, at the C3 and C4 positions of the pyrazolone ring.

Copper-catalyzed asymmetric alkynylation of pyrazole-4,5-diones using chloramphenicol base-derived hydroxyl oxazoline ligands

The asymmetric copper-catalyzed alkynylation reactions of pyrazole 4,5-diones in the presence of hydroxyl oxazoline ligand, which was derived from low cost, easily accessible chloramphenicol base (ANP), were achieved. The notable...

Synthesis, molecular docking and mosquitocidal efficacy of lawsone and its derivatives against the dengue vector Aedes aegypti L. (Diptera: Culicidae)

BACKGROUND

Aedes aegypti is the primary dengue vector, a significant public health problem in many countries. Controlling the growth of Ae. aegypti is the biggest challenge in the mosquito control program, and there is a need for finding bioactive molecules to control Ae. aegypti in order to prevent dengue virus transmission.

OBJECTIVE

To assess the mosquitocidal property of lawsone and its 3-methyl-4H-chromen-3-yl-1-phenylbenzo[6,7]chromeno[2,3,c]pyrazole-dione derivatives (6a-6h) against various life stages of Ae. aegypti. Besides, to study the mode of action of the active compound by molecular docking and histopathological analysis.

METHODS

All derivatives were synthesized from the reaction between 2-hydroxy-1,4-naphthoquinone, chromene-3-carbaldehyde, and 1-phenyl-3-methyl-pyrazol-5-one by using one pot sequential multicomponent reaction. The mosquito life stages were subjected to diverse concentrations ranging from 1.25, 2.5, 5.0, and 10 ppm for lawsone and its derivatives. The structure of all synthesized compounds was characterized by spectroscopic analysis. Docking analysis was performed using autodock tools. Midgut sections of Ae. aegypti larvae were analyzed for histopathological effects.

RESULTS

Among the nine compounds screened, derivative 6e showed the highest mortality on Ae. aegypti life stages. The analyzed LC50 and LC90 results of derivative 6e were 3.01, 5.87 ppm, and 3.41, 6.28 ppm on larvae and pupae of Ae. aegypti, respectively. In the ovicidal assay, the derivative 6e recorded 47.2% egg mortality after 96-hour post-exposure to 10 ppm concentration. In molecular docking analysis, the derivative 6e confirmed strong binding interaction (-9.09 kcal/mol and -10.17 kcal/mol) with VAL 60 and HIS 62 of acetylcholinesterase 1 (AChE1) model and LYS 255, LYS 263 of kynurenine aminotransferase of Ae. aegypti, respectively. The histopathological results showed that the derivative 6e affected the columnar epithelial cells (CC) and peritrophic membrane (pM).

CONCLUSION

The derivative 6e is highly effective in the life stages of Ae. aegypti mosquito and it could be used in the integrated mosquito management programme.

Highly Chemoselective [2+1] Annulation of α-Alkylidene Pyrazolones with α-Bromonitroalkenes: Synthesis of Pyrazolone-Based Vinylcyclopropanes and Computational Studies

A highly chemoselective [2+1] annulation of α-alkylidene pyrazolones with α-bromonitroalkenes has been achieved under mild conditions. α-Alkylidene pyrazolones were unprecedentedly used as a C1 synthon to participate in annulation reactions, providing access to diverse vinylcyclopropane-based pyrazolone products. In addition, a spectrum of pharmaceutically interesting pyrazole-fused pyranone oximes could be rapidly obtained through a [2+1] annulation/rearrangement sequential process. Computational studies disclosed the origin of the observed chemoselectivity of the [2+1] cycloaddition.

The chemistry of 4-(dicyanomethylene)-3-methyl-l-phenyl-2-pyrazoline-5- ones as a privileged scaffold in synthesis of heterocycles

BACKGROUND

The reactivity of 4-(dicyanomethylene)-3-methyl-l-phenyl-2-pyrazoline-5-one DCNP 1 and its derivatives makes it valuable as a building block for the synthesis of heterocyclic compounds like pyrazolo-imidazoles, - thiazoles, spiropyridines, spiropyrroles, spiropyrans and others. As a number of publications have reported on the reactivity of DCNP and its derivatives, we compiled some features of this interesting molecule.

OBJECTIVE

This article aims to review the preparation of DCNP, its reactivity and application in heterocyclic and dyes synthesis.

CONCLUSION

In this review we have provided an overview of recent progress in the chemistry of DCNP and its significance in synthesis of various classes of heterocyclic compounds and dyes. The unique reactivity of DCNP offers unprecedentedly mild reaction conditions for the generation of versatile cynomethylene dyes from a wide range of precursors including amines, α-aminocarboxylic acids, their esters, phenols, malononitriles and azacrown ethers. We anticipate that more innovative transformations involving DCNP will continue to emerge in the near future.

Aloe emodin inhibits telomerase activity in breast cancer cells: transcriptional and enzymological mechanism

BACKGROUND

Telomerase plays an essential role in cancer cell proliferation. In this study, we investigated inhibition mechanism of aloe emodin (AE) on three different types of breast cancer cell lines, MDA-MB-453, MDA-MB-231 and MCF-7.

METHODS

The cells were treated with different concentrations of AE. Relative length of telomere and human telomerase reverse-transcriptase (hTERT) mRNA level was analyzed by quantitative PCR (qPCR). Protein level was assayed by Western blot. Sodium bisulfite methylation sequencing was performed to assess the methylation status of gene promoter. Enzymology kinetics was applied to reveal the interaction between AE and telomerase. Ultraviolet-visible titration and fluorescence resonance energy transfer (FRET) melting experiment were carried out to study the interaction between AE and telomeric DNA.

RESULTS

Continuous AE exposure of these cells for 48 h results in shortening of telomeres and inhibition of telomerase. The transcription of hTERT was repressed by activation of E2F1 and inactivation of c-myc proteins. Significant demethylation of CpG islands in hTERT gene promoter was observed in MDA-MB-453 and MCF-7 cells. AE competed with dNTP for occupation of the enzyme active site. AE was a telomeric G-quadruplex structure stabilizer as indicated by titration test and FRET experiments.

CONCLUSIONS

AE was a competitive inhibitor of telomerase and a G-quadruplex structure stabilizer. AE decreased the transcription of hTERT gene in the three breast cancer cell lines via up-regulation E2F1 and down-regulation c-myc expressions. The suppressed transcription was also related to the demethylation of the gene promoter.

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.

Pyrazolone: a powerful synthon for asymmetric diverse derivatizations

This feature article reports recent advances in the asymmetric diverse derivatizations of the pyrazolone scaffold.

DABCO-catalyzed silver-promoted direct thiolation of pyrazolones with diaryl disulfides

Efficient direct thiolation of N-substituted pyrazolones with diaryl disulfides was developed using a combination of DABCO and AgOAc to assist C–S bond formation.

Nanofibrous matrixes with biologically active hydroxybenzophenazine pyrazolone compound for cancer theranostics

The nanomaterial with the novel biologically active compounds has been actively investigated for application in cancer research. Substantial use of nanofibrous scaffold for cancer research with potentially bioactive compounds through electrospinning has not been fully explored. Here, we describe the series of fabrication of nanofibrous scaffold loaded with novel potential biologically active hydroxybenzo[a]phenazine pyrazol-5(4H)-one derivatives were designed, synthesized by a simple one-pot, two step four component condensation based on Michael type addition reaction of lawsone, benzene-1,2-diamine, aromatic aldehydes and 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one as the substrates. The heterogeneous solid state catalyst (Fe (III) Y-Zeolite) could effectively catalyze the reaction to obtain the product with high yield and short reaction time. The synthesized compounds (5a-5p) were analyzed by NMR, FTIR and HRMS analysis. Compound 5c was confirmed by single crystal XRD studies. All the compounds were biologically evaluated for their potential inhibitory effect on anticancer (MCF-7, Hep-2) and microbial (MRSA, MTCC 201 and FRCA) activities. Among the compounds 5i exhibited the highest levels of inhibitory activity against both MCF-7, Hep-2 cell lines. Furthermore, the compound 5i (BPP) was evaluated for DNA fragmentation, flow cytometry studies and cytotoxicity against MCF-7, Hep-2 and NIH 3T3 fibroblast cell lines. In addition, molecular docking (PDB ID: 1T46) studies were performed to predict the binding affinity of ligand with receptor. Moreover, the synthesized BPP compound was loaded in to the PHB-PCL nanofibrous scaffold to check the cytotoxicity against the MCF-7, Hep-2 and NIH 3T3 fibroblast cell lines. The in vitro apoptotic potential of the PHB-PCL-BPP nanofibrous scaffold was assessed against MCF-7, Hep-2 cancerous cells and fibroblast cells at 12, 24 and 48h respectively. The nanofibrous scaffold with BPP can induce apoptosis and also suppress the proliferation of cancerous cells. We anticipate that our results can provide better potential research in nanomaterial based cancer research.

An SiO2/ZnBr2 mediated expeditious approach to 3-methyl-1-phenyl-1H-pyrazol-5(4H)-one derivatives in water under microwave irradiation

An efficient and eco-friendly synthesis of pyrazolone derivatives.

Asymmetric chlorination of 4-substituted pyrazolones catalyzed by natural cinchona alkaloid

A natural quinidine catalyzed asymmetric chlorination of 4-substituted pyrazolones was revealed in high yield and excellent enantioselectivity.

DNA, the biopolymer as a target material for metalloinsertors: From chemistry to preclinical implications

The coordination of therapeutically interesting designed complexes of stoichiometry [ML(Met)Cl2] [where M=Cu(II), Co(II), Ni(II), Mn(II) and Zn(II), L=benzylidene-4-aminoantipyrine and Met=methionine] has been ascertained on the basis of physicochemical techniques. Their interaction with CT DNA reveals that they are good intercalators. The anticancer mechanism of our complexes is documented from their enhanced DNA splitting personalities under physiological conditions. To reveal the chemotherapeutic action of these complexes, we explored the inflammatory response, analgesic and antioxidant activities. Moreover, all the complexes show good antimicrobial activity against few bacterial and fungal strains. Our study has identified the mechanism of action of these complexes on inhibiting tumor cells and suggested that they have great potential as novel anticancer agents.

Synthesis, characterization and anti-breast cancer activity of new 4-aminoantipyrine-based heterocycles

4-Aminoantipyrine was utilized as key intermediate for the synthesis of pyrazolone derivatives bearing biologically active moieties. The newly synthesized compounds were characterized by IR, ¹H- and ¹³C-NMR spectral and microanalytical studies. The compounds were screened as anticancer agents against a human tumor breast cancer cell line MCF7, and the results showed that (Z)-4-((3-amino-5-imino-1-phenyl-1H-pyrazol-4(5H)-ylidene)methylamino)-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one 5, 3-(4-bromophenyl) -1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile 13, 1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1-Hpyrazol- 4-yl)-3-(4-iodophenyl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile 14, 3,3′-(4,4′-sulfonylbis(4,1-phenylene))bis(1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol- 4-yl)-4-oxo-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carbonitrile) 16, (Z)-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-2-hydrazono-4-oxo-3-phenyl-1,2,3,4-tetrahydropyrimidine-5-carbonitrile 17, (Z)-1-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-4-oxo-3-phenyl-2-(2-phenylhydrazono)-1,2,3,4-tetrahydro pyrimidine-5-carbonitrile 18, and (Z)-4-(3-amino-6-hydrazono-7-phenyl-6,7-dihydro pyrazolo[3,4-d]pyrimidin-5-yl)-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one 19 were the most active compounds with IC₅₀ values ranging from 30.68 to 60.72 μM compared with Doxorubicin as positive control with the IC₅₀ value 71.8 μM.

2-Hydroxyethylammonium acetate as a reusable and cost-effective ionic liquid for the efficient synthesis of bis(pyrazolyl)methanes and 2-pyrazolyl-1-nitroalkanes

A new and convenient method for the synthesis of bis(pyrazolyl)methanes by one-pot tandem Knoevenagel–Michael reaction of 3-methyl-1-phenyl-5-pyrazolone with aryl, heteroaryl, or alkyl aldehydes in the presence of 2-hydroxyethylammonium acetate (2-HEAA) as a task-specific ionic liquid is described. This method was also successfully applied for the synthesis of 2-pyrazolyl-1-nitroalkanes by Michael addition of 3-methyl-1-phenyl-5-pyrazolone with β-nitrostyrenes in short reaction times. The present protocol offers several advantages such as using a reusable and cost-effective ionic liquid, an environmentally benign reaction media, being amenable to scale-up and good to high yields of the products.