Perspective: the potential of pyrazole-based compounds in medicine

Direct Construction of 1,4-Dihydropyridazines and Pyrazoles via Annulation of Alkyl 2-Aroyl-1-chlorocyclopropanecarboxylates

An efficient and chemodivergent synthesis of highly functionalized 1,4-dihydropyridazines and pyrazoles has been accomplished via base-promoted annulation between hydrazones and alkyl 2-aroyl-1-chlorocyclopropanecarboxylates, respectively. This transition-metal-free domino reaction proceeded rapidly under mild basic conditions, affording potentially bioactive 1,4-dihydropyridazine and pyrazole derivatives in moderate yields. The conversion of 1,4-dihydropyridazine to pyrazole was confirmed by adjusting the quantity of the base.

Anticancer Effects of the Novel Pyrazolyl-Urea GeGe-3

In a screen of over 200 novel pyrazole compounds, ethyl 1-(2-hydroxypentyl)-5-(3-(3-(trifluoromethyl) phenyl)ureido)-1H-pyrazole-4-carboxylate (named GeGe-3) has emerged as a potential anticancer compound. GeGe-3 displays potent anti-angiogenic properties through the presumptive targeting of the protein kinase DMPK1 and the Ca2+-binding protein calreticulin. We further explored the anticancer potential of GeGe-3 on a range of established cancer cell lines, including PC3 (prostate adenocarcinoma), SKMEL-28 (cutaneous melanoma), SKOV-3 (ovarian adenocarcinoma), Hep-G2 (hepatocellular carcinoma), MDA-MB231, SKBR3, MCF7 (breast adenocarcinoma), A549 (lung carcinoma), and HeLa (cervix epithelioid carcinoma). At concentrations in the range of 10 μM, GeGe-3 significantly restricted cell proliferation and metabolism. GeGe-3 also reduced PC3 cell migration in a standard wound closure and trans-well assay. Together, these results confirm the anticancer potential of GeGe-3 and underline the need for more detailed pre-clinical investigations into its molecular targets and mechanisms of action.

Pyrazole-based and N,N-diethylcarbamate functionalized some novel aurone analogs: Design, synthesis, cytotoxic evaluation, docking and SAR studies, against AGS cancer cell line

The present study involves the design, synthesis, and biological evaluation of a series of thirty-three, pyrazole-based and N,N-diethylcarbamate functionalized, novel aurone analogs, against AGS cancer cell line. These novel aurone analogs are obtained from the reaction of pyrazole-based 6-hydroxyaurones with diethyl carbamoyl chloride using mild basic reagent. The cytotoxic activities of these compounds were evaluated against a human gastric adenocarcinoma cell line (AGS) and disclosed some potential outcomes as several analogs were found to have cytotoxicity better than the reference drugs Oxaliplatin and Leucovorin. The structure-activity relationship (SAR) study further unveiled the critical role of replacing the hydroxyl group in ring A with a carbamoyl group for cytotoxic activity. Among these aurone analogs, 8e and 8f, with IC50 values of 6.5 ± 0.024 μM and 6.6 ± 0.035 μM, respectively, are identified as the most active compounds. Molecular docking studies were conducted against HER2, a human epidermal growth factor involved in gastric and ovarian cancer, to investigate the binding interactions between the compounds and the protein HER2, where7e and 8e exhibited maximum interactions.

An efficient one-pot synthesis of pyrazole complexes formed in situ: synthesis, crystal structure, Hirshfeld surface analysis and in vitro biological properties

The molecular crystals of monomeric and dimeric pyrazole complexes were prepared via one-pot syntheses. These are dichloridobis(3,5-dimethyl-1H-pyrazole-κN1)cobalt/zinc(0.2/0.8), [Co0.20Zn0.80Cl2(C5H8N2)2] or [Co0.2Zn0.8Cl2(3,5-dmp)2] (1), and bis(μ-3,5-dimethyl-1H-pyrazole)-κ2N1:N2;κ2N2:N1-bis[bromido/chlorido(0.7/0.3)bis(3,5-dimethyl-1H-pyrazole-κN1)cobalt/zinc(0.1/0.9)], [Co0.20Zn1.80Br1.40Cl0.60(C5H7N2)2(C5H8N2)2] or [Co0.1Zn0.9Br0.7Cl0.3(μ-3,5-dmp)(3,5-dmp)]2 (2). The isolated complexes contain 3,5-dimethylpyrazole (3,5-dmp) ligands formed in situ from the decomposition of 1-hydroxymethyl-3,5-dimethylpyrazole. In both isolated complexes, some positional disorder is observed at the metal ions and halogen ligands. The molecular crystals of 1 and 2 are centrosymmetric, with the space groups C2/c and P-1, respectively. Additionally, in the dinuclear complex, the pyrazole ring has a bridging coordination function with respect to the metal ions. Both complexes have good biological activities against cancer cells. The results of an in vitro cytotoxicity study indicated that compounds 1 and 2 showed significant cytotoxicity for cancer cell lines, including hepatic (HepG2 cells), lung (A549 cells) and colon cancer cells (SW 480 and SW 620). Based on the calculated IC50 values against human cancer cell lines, it was found that both complexes demonstrated potent antiproliferative activity combined with great selectivity towards cancer cells. Complex 2 was a more effective cytotoxic agent which, at the same time, exhibited high cytocompatibility. The obtained data are very encouraging and could be useful for anticancer drug discovery.

A novel pyrazolone complex P-FAH-Cu-bpy induces death of Escherichia coli and Staphylococcus aureus by disrupting cell structure and blocking energy

A novel pyrazolone-based copper complex [Cu(L)(bpy)]∙CH3OH (P-FAH-Cu-bpy) was synthesized and previously characterized to have antitumor properties. This study aimed to investigate its antibacterial properties and action modes against Escherichia coli and Staphylococcus aureus. By agar diffusion assay, P-FAH-Cu-bpy showed strong antibacterial activity against E. coli and S. aureus with the diameter of inhibition zone of 10.17-12.50 mm and 11.83-14 mm, respectively. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the complex were 1.5 and 3 μM, respectively. Destroyed bacteria cells and debris were clearly observed by SEM. At 2 MIC and 4 MIC of P-FAH-Cu-bpy, 1.1683 and 1.9083 pg copper per cell was taken by E. coli, and 4.5670 and 8.5250 pg per cell by S. aureus, respectively. Multi-step resistance selection showed both bacteria were sensitive to P-FAH-Cu-bpy without induction of resistance within 30 generations. With P-FAH-Cu-bpy treatment, the release of nucleotides and proteins and alkaline phosphatase was increased, but the activity of K+-Na+-ATPase and Ca2+-Mg2+-ATPase and membrane conductivity were decreased in both pathogens. In conclusion, P-FAH-Cu-bpy induced death of both bacteria by destroying the cell membrane structure and blocking energy and exhibited strong antibacterial activity against E. coli and S. aureus without inducing microbial resistance.

Unravelling the synthetic and therapeutic aspects of five, six and fused heterocycles using Vilsmeier-Haack reagent

The aim of this review is to encapsulate the synthetic protocols and medicinal aspects of a wide range of heterocyclic compounds using the Vilsmeier-Haack (V. H.) reagent. These derivatives act as excellent precursors having different aryl ring functionalities and could be used for the synthesis of a variety of heterocyclic scaffolds. The V. H. reagent, a versatile reagent in organic chemistry, is used to formylate various heterocyclic compounds of medicinal interest. Due to the different chemical interactions, efficacy, and potency of V. H. reagents, plenty of heterocyclic compounds can be synthesized which serve as a constituent in various novel medications and acts as a bridge between biology and chemistry. These carboxylate moieties can effectively cooperate as precursors for several multi-component reactions (MCR) including Strecker synthesis, Bucherer-Berg reaction and post-MCR cyclization, modified variants with various pharmaceutical applications such as anti-tumor, anti-convulsant, anti-chitosomal and so on.

Cytotoxic and immunomodulatory potential of a novel [2-(4-(2,5-dimethyl-1H-pyrrol-1-yl)-1H-pyrazol-3-yl)pyridine] in myeloid leukemia

Cancer ranks among the leading causes of mortality worldwide. However, the efficacy of commercially available anticancer drugs is compromised by the emerging challenge of drug resistance. This study aimed to investigate the anticancer and immunomodulatory potential of a recently developed a novel [2-(4-(2,5-dimethyl-1 H-pyrrol-1-yl)- 1 H-pyrazol-3-yl) pyridine]. The cytotoxic potential of the compound was assessed using the MTT assay on both cancerous HL60 (acute myeloid leukemia) and K562 (chronic myeloid leukemia) cell lines, as well as non-cancerous Vero cells and human peripheral blood mononuclear cells (PBMCs). A clonogenic assay was employed to evaluate the anticancer efficacy of the compound, while flow cytometry was utilized to investigate its effect on cell cycle arrest. Furthermore, the immunomodulatory potential of the compound was assessed by quantifying inflammatory and anti-inflammatory biomarkers in the supernatant of PBMCs previously treated with the compound. Our study revealed that the novel pyridine ensemble exhibits selective cytotoxicity against HL60 (IC₅₀ = 25.93 µg/mL) and K562 (IC₅₀ = 10.42 µg/mL) cell lines, while displaying no significant cytotoxic effect on non-cancerous cells. In addition, the compound induced a decrease of 18% and 19% in the overall activity of COX-1 and COX-2, respectively. Concurrently, it upregulated the expression of cytokines including IL4, IL6, IL10, and IL12/23p40, while downregulating INFγ expression. These findings suggest that the compound has the potential to serve as a promising candidate for the treatment of acute and chronic myeloid leukemias due to its effective antiproliferative and immunomodulatory activities, without causing cytotoxicity in non-cancerous cells.

Pyrazole/pyrazoline as an excellent pharmacophore in the design of carbonic anhydrase inhibitors (2018-2022)

Carbonic anhydrase (CA) is a metalloenzyme that catalyzes the interconversion between carbon dioxide and water and dissociated ions of carbonic acid. In addition, CA performs various other functions in animals and plants, depending on the part of the living being. CAs have been found in almost all organisms. Besides, CAs are associated with several diseases, such as glaucoma, obesity, epilepsy, cancer, and so on. CAs are also involved in tumor cell growth and angiogenesis. Thus, inhibition of CA may be an attractive way of control of such diseases. Hence, CA inhibitors have been designed and developed to cure CA-associated diseases. Some examples of approved CA inhibitors are dorzolamide, methazolamide, brinzolamide, and dichlorphenamide. Furthermore, various heterocyclic scaffolds were utilized for the design of CA inhibitors. Among those, pyrazole/pyrazoline derivatives have exhibited greater potency toward CA inhibition. Hence, research that took place in the field of drug design and discovery of CA inhibition has been systematically reviewed and collated. Alongside, the structure-activity relationship has been described, followed by a description of the most potent molecules and their structural features.

The sensitive detection and mechanism of Fe-3,5-dimethyl pyrazole fluorescent sensor to diethylenetriamine pentamethylene phosphonic acid: Experimental study and quantum chemical calculation

Diethylenetriamine pentamethylene phosphonic acid (DTPMP) is one of the most commonly used amino organic phosphonates. The existing methods for DTPMP detection are complicated, time-consuming, and cannot detect trace DTPMP in the natural environment. In the present work, the Fe-based 3,5-dimethyl pyrazole fluorescent sensor (Fe-DP) was constructed. The addition of Fe³⁺ to DP solution can greatly decrease the fluorescent intensity of DP, while the addition of different concentrations of DTPMP will restore the fluorescence intensity of DP to different degrees, to achieve quantitative detection of DTPMP, and the detection limit (LOD) of DTPMP was lower as 0.105 μΜ. The Fe-DP fluorescent sensor exhibited excellent anti-interference ability and good stability. Moreover, the fluorescence quenching mechanism of DP by Fe³⁺ was revealed by UV absorption spectrum and Multiwfn wavefunction analysis based on density function theory (DFT). The results revealed that the excitation of DP belonged to local excitation, in which the electrons were donated primarily by the N atom with double bond and redistributed within the pyrazole ring.The fluorescence quenching of adding Fe³⁺ was not caused by resonance energy transfer or charge transfer, which did not belong to dynamic quenching, but due to the ground state complex formed by the coordination of Fe³⁺ and the double bond N atom on the DP pyrazole ring.

5-(4-Fluorophenyl)-1-[4-(4-methylphenyl)thiazol-2-yl]-3-[4-(prop-2-ynyloxy)phenyl]-4,5-dihydro-1H-pyrazole

In the title compound, C28H22FN3OS, four rings are almost coplanar, with the fluorophenyl ring substantially twisted. In the extended structure, aromatic π–π stacking interactions between the pyrazole ring and the tolyl ring link the molecules into centrosymmetric dimers.

Seeking heterocyclic scaffolds as antivirals against dengue virus

Dengue is one of the most typical viral infection categorized in the Neglected Tropical Diseases (NTDs). It is transmitted via the female Aedes aegypti mosquito to humans and majorly puts risk to the lives of more than half of the world. Recent advancements in medicinal chemistry have led to the design and development of numerous potential heterocyclic scaffolds as antiviral drug candidates for the inhibition of the dengue virus (DENV). Thus, in this review, we have discussed the significance of inhibitory and antiviral activities of nitrogen, oxygen, and mixed (nitrogen-sulfur and nitrogen-oxygen) heterocyclic scaffolds that are published in the last seven years (2016–2022). Furthermore, we have also discussed the probable mechanisms of action and the diverse structure-activity relationships (SARs) of the heterocyclic scaffolds. In addition, this review has elaborately outlined the mechanism of viral infection and the life cycle of DENV in the host cells. The wide set of heterocycles and their SARs will aid in the development of pharmaceuticals that will allow the researchers to synthesize the promising anti-dengue drug candidate in the future.

Synthesis, Physicochemical, Thermal and Antioxidative Properties of Zn(II) Coordination Compounds with Pyrazole-Type Ligand

The reactions of pyrazole derivative, i.e., ethyl-5-amino-1-methyl-1H-pyrazole-4-carboxylate (L) with zinc halogenides in methanolic solution and zinc nitrate and zinc acetate in acetonic solution are described. The formulae of synthesized compounds are ZnL2Cl2 (1), [ZnL2Br2] (2), ZnL2I2·0.5MeOH (3), [Zn(L)2(H2O)4](NO3)2 (4), and {ZnL(OAc)2}2 (5). Two complexes are obtained in form of single crystals: [ZnL2Br2] (2) and [Zn(L)2(H2O)4](NO3)2 (4). Their crystal and molecular structure were determined by single-crystal X-ray structure analysis. The FTIR spectra of compounds prove the complex formation with all five zinc salts. The complexes are characterized by conductometric and thermoanalytical measurements, and their antioxidative activity was also tested by the scavenging effect on the DPPH radical. Conductometric results, solvolytic stability, and antioxidative activity of the compounds are in correlation.

Recent development of imidazole derivatives as potential anticancer agents

Cancer, one of the key health problems globally, is a group of related diseases that share a number of characteristics primarily the uncontrolled growth and invasive to surrounding tissues. Chemotherapy is one of the ways for the treatment of cancer which uses one or more anticancer agents as per chemotherapy regimen. Limitations of most anticancer drugs due to a variety of reasons such as serious side effects, drug resistance, lack of sensitivity and efficacy etc. generate the necessity towards the designing of novel anticancer lead molecules. In this regard, the synthesis of biologically active heterocyclic molecules is an appealing research area. Among heterocyclic compounds, nitrogen containing heterocyclic molecules has fascinated tremendous consideration due to broad range of pharmaceutical activity. Imidazoles, extensively present in natural products as well as synthetic molecules, have two nitrogen atoms, and are five membered heterocyclic rings. Because of their countless physiological and pharmacological characteristics, medicinal chemists are enthused to design and synthesize new imidazole derivatives with improved pharmacodynamic and pharmacokinetic properties. The aim of this present chapter is to discuss the synthesis, chemistry, pharmacological activity, and scope of imidazole-based molecules in anticancer drug development. Finally, we have discussed the current challenges and future perspectives of imidazole-based derivatives in anticancer drug development.

Influence of ligand lipophilicity in Pt(II) complexes on their antiproliferative and apoptotic activities in tumour cell lines

One of the most widely used strategies for drug development is the coordination of bioactive ligands to transition metals, which could improve biological activity. Moreover, the incorporation of aromatic groups to ligands may allow an enhanced lipophilicity that can influence the cellular uptake and accumulation of the metallodrugs, thus increasing their activity. Herein, we have reported the synthesis and characterization of four Pt(II) complexes [PtCl₂(L)], where L = 2-(1-pyrazolyl)-2-thiazoline (PzTn), 2-(1-pyrazolyl)-1,3-thiazine (PzTz), 2-(3,5-diphenyl-1-pyrazolyl)-2-thiazoline (DPhPzTn) or 2-(3,5-diphenyl-1-pyrazolyl)-1,3-thiazine (DPhPzTz). The study was aimed at analysing their potential anticarcinogenic ability in epithelial cervix carcinoma HeLa, human promyelocytic leukemia HL-60 and human histiocytic lymphoma U-937 tumour cell lines as well as checking whether the structural factors of the organic ligand may influence their biological activity. Our findings showed that PtDPhPzTn and PtDPhPzTz were far more effective in terms of cytotoxicity than their less lipophilic counterparts (PtPzTn and PtPzTz), especially in cells derived from solid cervical tumours, thereby suggesting that modulating the lipophilicity of the ligands can help improve the cytotoxic effect of the metal complexes.

Construction of Spirooxindole Analogues Engrafted with Indole and Pyrazole Scaffolds as Acetylcholinesterase Inhibitors

Twenty-five new hits of spirooxindole analogs 8a-y engrafted with indole and pyrazole scaffolds were designed and constructed via a [3+2]cycloaddition (32CA) reaction starting from three components: new chalcone-based indole and pyrazole scaffolds 5a-d, substituted isatins 6a-c, and secondary amines 7a-d. The potency of the compounds were assessed in modulating cholinesterase (AChE) activity using Ellman's method. Compounds 8i and 8y showed the strongest acetylcholine esterase inhibition (AChEI) with IC50 values of 24.1 and 27.8 μM, respectively. Molecular docking was used to study their interaction with the active site of hAChE.

New 1,2,3-Triazole-Appended Bis-pyrazoles: Synthesis, Bioevaluation, and Molecular Docking

The present work describes design of a small library of new 1,2,3-triazole-appended bis-pyrazoles by using a molecular hybridization approach, and the synthesized hybrids were evaluated for their antifungal activity against different fungal strains, namely, Candida albicans, Cryptococcus neoformans, Candida glabrata, Candida tropicalis, Aspergillus niger, and Aspergillus fumigatus. All the compounds exhibited broad-spectrum activity against the tested fungal strains with excellent minimum inhibitory concentration values. The molecular docking study against sterol 14α-demethylase (CYP51) could provide valuable insights into the binding modes and affinity of these compounds. Furthermore, these compounds were also evaluated for their antioxidant activity, which also resulted in promising data.

Synthesis, characterization, and biological evaluation of new copper complexes of naphthyl pyrazole ligands

Two naphthalene pyrazole ligands were synthesized using KOH/DMSO and Cu catalyst and characterized with FT-IR, ESI-MS, ¹H, and ¹³C NMR spectroscopies. The crystal structures of 1-(2-methylnaphthalen-1-yl)-1H-pyrazole (MeNap-Pz) ligand have been determined with X-ray crystal structure analysis. Reaction of the ligands with Cu(NO₃)₂x3.5H₂O gave two new complexes and characterized with magnetic susceptibility, molar conductance, FT-IR, LCMS-MS, ICP-OES, NMR, thermogravimetric analysis, and ESR spectra. The spectral data of the ligands are coordinated to the metal ion through the nitrogen atoms of the pyrazole ring. Consequently, it has been determined that [Cu(MeNap-Pz)₂(NO₃)]NO₃.2H₂O complex showed square planar geometry and [Cu(NapMe-Pz)₂(NO₃)₂].H₂O complex showed octahedral geometry. All compounds were screened for in vitro antibacterial activity and copper complexes have been shown to be effective on bacteria.

Aldehydes as Photoremovable Directing Groups: Synthesis of Pyrazoles by a Photocatalyzed [3+2] Cycloaddition/Norrish Type Fragmentation Sequence

A straightforward methodology for the regioselective synthesis of pyrazoles has been developed by a domino sequence based on a photoclick cycloaddition followed by a photocatalyzed oxidative deformylation reaction. Distinguishing features of this protocol include an unprecedented photoredox-catalyzed Norrish type fragmentation under green-light irradiation and the use of α,β-unsaturated aldehydes as synthetic equivalents of alkynes, where the aldehyde is acting as a novel photoremovable directing group.

Design, synthesis and in vitro antitumor evaluation of novel pyrazole-benzimidazole derivatives

A series of novel pyrazole-benzimidazole derivatives (6-42) have been designed, synthesized and evaluated for their in vitro antiproliferative activity against the HCT116, MCF-7 and Huh-7 cell lines. Among them, compounds 17, 26 and 35 showed significant antiproliferative activity against HCT116 cell lines with the IC₅₀ values of 4.33, 5.15 and 4.84 μM, respectively. Moreover, fluorescent staining studies showed compound 17 could induce cancer cells apoptosis. The flow cytometry assay revealed that compound 17 could induce cell cycle arrest at G0/G1 phase. All in all, these consequences suggest that pyrazole-benzimidazole derivatives could serve as promising compounds for further research to develop novel and highly potent cancer therapy agents.

Antimigratory effect of pyrazole derivatives through the induction of STAT1 phosphorylation in A549 cancer cells

OBJECTIVES

In cancer treatment, it is important to prevent or slow down metastasis as well as preventing the proliferation of cancer cells. In this study, we aimed to find pyrazole compounds with antimigratory properties.

METHODS

The 'PASSonline' programme was used to determine the possible pharmacological activities of the pyrazole compounds selected from the library, and two pyrazole derivatives were identified as a transcription factor STAT inhibitor with a high probability. There are studies known that JAK/STAT pathway is related to cancer cell migration, thus the possible antimigratory effects of these two synthesized pyrazole compounds were examined in A549 cancer cells.

KEY FINDINGS

Our data demonstrated that compound-2 at different concentrations significantly inhibited cell migration in A549 cells. Then, the effects of these compounds on STAT activation were evaluated. We reported that 10 µM compound-2 induced a significant phosphorylation of STAT1 suggesting that STAT1 activation may be responsible for the antimigratory effect of compound-2.

CONCLUSIONS

Taken together, the compound-2 is a promising compound with the antimigratory activity for cancer treatment, and further studies are needed to synthesize more active derivatives by evaluating the structure-activity relationship of leading compound-2.

Multicomponent reactions as a potent tool for the synthesis of benzodiazepines

Benzodiazepines (BZDs), a diverse class of benzofused seven-membered N-heterocycles, display essential pharmacological properties and play vital roles in some biochemical processes. They have mainly been prescribed as potential therapeutic agents, which interestingly represent various biological activities such as anticancer, anxiolytic, antipsychotic, anticonvulsant, antituberculosis, muscle relaxant, and antimicrobial activities. The extensive biological activities of BZDs in various fields have encouraged medicinal chemists to discover and design novel BZD-based scaffolds as potential therapeutic candidates with the favorite biological activity through an efficient protocol. Although certainly valuable and important, conventional synthetic routes to these bicyclic benzene compounds contain methodologies often requiring multistep procedures, which suffer from waste materials generation and lack of sustainability. By contrast, multicomponent reactions (MCRs) have recently advanced as a green synthetic strategy for synthesizing BZDs with the desired scope. In this regard, MCRs, especially Ugi and Ugi-type reactions, efficiently and conveniently supply various complex synthons, which can easily be converted to the BZDs via suitable post-transformations. Also, MCRs, especially Mannich-type reactions, provide speedy and economic approaches for the one-pot and one-step synthesis of BZDs. As a result, various functionalized-BZDs have been achieved by developing mild, efficient, and high-yielding MCR protocols. This review covers all aspects of the synthesis of BZDs with a particular focus on the MCRs as well as the mechanism chemistry of synthetic protocols. The present manuscript opens a new avenue for organic, medicinal, and industrial chemists to design safe, environmentally benign, and economical methods for the synthesis of new and known BZDs.

Spectroscopic Study of the Molecular Structure of the New Hybrid with a Potential Two-Way Antibacterial Effect

Bacterial strains become resistant to almost all classes of antibiotics, which makes it necessary to look for new substitutes. The non-absorbable ciprofloxacin–biguanide bismuth complex, used locally, may be a good alternative to a conventional therapy. The purpose of this study was to study the structure of the proposed ciprofloxacin (CIP) -bismuth(III)—chlorhexidine (CHX) composite (CIP-Bi-CHX). The spectroscopic techniques such as UV-VIS (ultraviolet-visible) spectroscopy, FTIR (Fourier-transform infrared) spectroscopy and NMR (Nuclear Magnetic Resonance) spectroscopy were used for structure characterization of the hybrid compound. The performed analysis confirmed the presence of the two active components—CIP and CHX and revealed the possible coordination sites of the ligands with bismuth ion in the metallo-organic structure. Spectroscopic study showed that the complexation between Bi(III) and CIP occurs through the carboxylate and ketone groups of the quinolone ring, while CHX combines with the central ion via the biguanide moieties.

Monoallylation and benzylation of dicarbonyl compounds with alcohols catalysed by a cationic cobalt(iii) compound

Monoallylation and monoalkylation of diketones and β-keto esters with allylic and benzylic alcohols catalysed by [Cp*Co(CH3CN)3][SbF6]2 (I) are reported. The method does not require any additive and affords regioselective products. The mechanistic investigations were done by in situ 1H NMR spectroscopy as well as control experiments. It has been shown that reactions proceed via η3-allyl complex formation or ally ether intermediate. The alkylation takes place via only ether intermediate. The resulting allylated and alkylated products have been used for the synthesis of eleven new trisubstituted pyrazoles and one pyrazolone.

Synthesis of novel pyrazole tagged pyridine derivatives; their antimicrobial activity

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Novel pyrazole tagged pyridine derivatives 5a-n synthesized starting from 3-cyano-4-trifluoromethyl-6- thiophenyl 2(1H) pyridone 1. Compound 1 on hydrolysis followed by decarboxylation resulted in 4-trifluoro-methyl-6- thiophenyl 2(1H)pyridone 2. Compound 2 treated with POCl3 to get 2- chloro-4-trifluoromethyl-6- thiophenyl pyridine 3 further reaction with hydrazine hydrate, which resulted in the formation of compound 4. Compound 4 on reaction with different substituted 1,3-diketones in ethanol reflux condition to afford pyrazole substituted pyridine derivatives 5a-n. All derivatives were tested against Gram-positive and Gram-negative bacterial strains and different Candida strains by well diffusion method, compounds 5k and 5l showed significant activity. The binding mode of 5k and 5l also studied by molecular docking studies.

Functionalisation of Fe3O4 nanoparticles by 2-((pyrazol-4-yl) methylene) hydrazinecarbothioamide enhances the apoptosis of human breast cancer MCF-7 cells

Cancer is a major cause of death. Thus, the incidence and mortality rate of cancer is globally important. Regarding vast problems caused by chemotherapy drugs, efforts have progressed to find new anti-cancer drugs. Pyrazole derivatives are known as components with anti-cancer properties. In here, Fe₃O₄ nanoparticles were first functionalized with (3-chloropropyl) trimethoxysilane, then 2-((pyrazol-4-yl) methylene) hydrazinecarbothioamide (P) was anchored on the surface of magnetic nanoparticles (PL). The synthesized nano-compounds were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, Zeta potential, dynamic light scattering, and energy-dispersive x-ray spectrometry analyses. The cytotoxicity effect was evaluated using MTT assay, apoptosis test by Flow cytometry, cell cycle analysis, Caspase-3 activity assay and Hoechst staining on MCF-7 cell line. The high toxicity for tumor cells and low toxicity on normal cells (MCF10A) was considered as an important feature (selectivity index, 10.9). Based on results, the IC50 for P and PL compounds were 157.80 and 131.84 μM/ml respectively. Moreover, apoptosis inducing, nuclear fragmentation, Caspase 3 activity and induction of cell rest in sub-G1 and S phases, were also observed. The inhibitory effect of PL was significantly higher than P, which could be due to the high penetrability of Fe₃O₄ nanoparticles.

Evaluation of antioxidant activity and toxicity of sulfur- or selenium-containing 4-(arylchalcogenyl)-1H-pyrazoles

Pyrazoles represent a significant class of heterocyclic compounds that exhibit pharmacological properties. The present study aimed to investigate the antioxidant potential of pyrazol derivative compounds in brain of mice in vitro and the effect of pyrazol derivative compounds in the oxidative damage and toxicity parameters in mouse brain and plasma of mice. The compounds tested were 3,5-dimethyl-1-phenyl-4-(phenylselanyl)-1H-pyrazol (1a), 3,5-dimethyl-4-(phenylselanyl)-1H-pyrazole (2a), 4-((4-methoxyphenyl)selanyl)-3,5-dimethyl-1-phenyl-1H-pyrazole (3a), 4-((4-chlorophenyl)selanyl)-3,5-dimethyl-1-phenyl-1H-pyrazole (4a), 3,5-dimethyl-1-phenyl-4-(phenylthio)-1H-pyrazole (1b), 3,5-dimethyl-4-(phenylthio)-1H-pyrazole (2b), 4-((4-methoxyphenyl)thio)-3,5-dimethyl-1-phenyl-1H-pyrazole (3b), 4-((4-chlorophenyl)thio)-3,5-dimethyl-1-phenyl-1H-pyrazole (4b), and 3,5-dimethyl-1-phenyl-1H-pyrazole (1c). In vitro, 4-(arylcalcogenyl)-1H-pyrazoles, at low molecular range, reduced lipid peroxidation and reactive species in mouse brain homogenates. The compounds also presented ferric-reducing ability as well nitric oxide-scavenging activity. Especially compounds 1a, 1b, and 1c presented efficiency to 1,1-diphenyl-2-picryl-hydrazyl-scavenging activity. Compounds 1b and 1c presented 2,20 -azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)-scavenging activity. In vivo assays demonstrated that compounds 1a, 1b, and 1c (300 mg/kg, intragastric, a single administration) did not cause alteration in the of δ-aminolevulinic acid dehydratase activity, an enzyme that exhibits high sensibility to prooxidants situations, in the brain, liver, and kidney of mice. Compound 1c reduced per se the lipid peroxidation in liver and brain of mice. Toxicological assays demonstrate that compounds 1a, 1b, and 1c did not present toxicity in the aspartate aminotransferase, alanine aminotransferase, urea, and creatinine levels in the plasma. In conclusion, the results demonstrated the antioxidant action of pyrazol derivative compounds in in vitro assays. Furthermore, the results showed low toxicity of compounds in in vivo assays.

Modified pyrazole platinum(II) complex can circumvent albumin and glutathione: Synthesis, structure and cytotoxic activity

The synthesis and structural characterization of novel platinum complexes ([Pt^II(Pz)₂Cl₂] - C1, C2 and C3) featuring diphenyl-pyrazole derived ligands: para-fluorophenyl and para-substituted phenyl (CH₃, F and Cl for L1, L2 and L3, respectively) were reported and it was also evaluated their potential antitumor activity. The elemental, molar conductivity and thermogravimetric analysis combined with FTIR, UV-vis, NMR and mass spectrometry are in agreement with the chemical structure indicated by single-crystal X-ray diffraction. The antiproliferative activities were assessed against tumor (B16F10 and 4T1) and non-tumor (BHK21) cell lines, and the cytotoxicity of the compounds was strongly increased after metal complexation displaying promising activity. It was also assessed the ability of extracellular bovine serum albumin (BSA) and glutathione (GSH) to decrease the cytotoxicity of the complexes against B16F10. It was highlighted that only the C3 activity was not disturbed in those conditions, being confirmed by flow cytometry using Anexin-V/PI to evaluate interferences in the apoptosis process, even it was not predicted by molecular docking simulations. The interaction of the synthesized compounds with calf-thymus DNA (ctDNA) and bovine serum albumin (BSA) was also investigated through spectrophotometric assays and molecular docking simulations, indicating that C1 and C2 presented better interaction with the biomacromolecules than the corresponding ligands. In addition, agarose gel electrophoresis with plasmid DNA revealed that C1-C3 are capable of interaction with DNA and modify its electrophoretic mobility.

Molecular Hybrids Integrated with Benzimidazole and Pyrazole Structural Motifs: Design, Synthesis, Biological Evaluation, and Molecular Docking Studies

Synthesis of a series of benzimidazole-ornamented pyrazoles, 6a-6j has been obtained from arylhydrazine and aralkyl ketones via a multistep synthetic strategy. Among them, a hybrid-possessing para-nitrophenyl moiety connected to a pyrazole scaffold (6a) exerted the highest anti-inflammatory activity, which is superior to the standard, diclofenac sodium. While executing the 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity, a hybrid-possessing para-bromophenyl unit integrated at the pyrazole structural motif (6i) exhibited the highest activity among the hybrids examined. Besides, evaluation of anticancer potency of the synthesized hybrids revealed that the one containing a para-fluorophenyl unit tethered at the pyrazole nucleus (6h) showed the highest activity against both the pancreatic cancer cells (SW1990 and AsPCl) investigated. Considerable binding affinity between B-cell lymphoma and the hybrid, 6h has been reflected while performing molecular docking studies (-8.65 kcal/mol). The outcomes of the investigation expose that these hybrids could be used as effective intermediates to construct more potent biological agents.