Synthesis and antimicrobial activity of some new pyrazole derivatives containing a ferrocene unit

Development and assessment of novel pyrazole-thiadiazol hybrid derivatives as VEGFR-2 inhibitors: design, synthesis, anticancer activity evaluation, molecular docking, and molecular dynamics simulation

Cancer remains a significant health challenge globally, requiring the development of targeted chemotherapeutics capable of specifically inhibiting cancer cell growth. Angiogenesis is one of the key features of tumor growth and metastasis and is, therefore, an important target for the treatment of many tumors. The vascular endothelial growth factor (VEGF) signaling pathway has proven to be a promising lead in anticancer therapy due to the central role it plays in tumor angiogenesis. Vascular endothelial growth factor receptor-2 (VEGFR-2) is a key mediator in the signaling pathway regulating angiogenesis. Targeting VEGFR-2 may disrupt angiogenesis, leading to a reduction in tumor blood supply and tumor progression. The design, synthesis, and assessment of novel VEGFR-2 inhibitor derivatives are the focus of this study, with particular emphasis on incorporating the pyrazole-thiadiazol pharmacophore into the molecular structure. Taking advantage of the pharmacophoric properties of pyrazole and 1,3,4-thiadiazol, compounds with different substituents in the main structure were designed and synthesized. The compounds were also evaluated for antiproliferative activity against cancer cell lines. Compound 4e demonstrated the highest activity among all compounds, with an IC50 of 9.673 ± 0.399 μM against HT-29 cells and 23.081 ± 0.400 μM against NIH3T3 cells. To further support the inhibitory activity of compound 4e, an in silico study was performed. Compound 4e demonstrated strong binding to the active site of VEGFR-2 in molecular docking studies, forming hydrogen bonds with key amino acid residues. The stability of the compound in the enzyme's active site was demonstrated through molecular dynamics simulations.

Synthesis, Electrochemical and Photochemical Properties of Sulfanyl Porphyrazine with Ferrocenyl Substituents

Ferrocene is useful in modern organometallic chemistry due to its versatile applications in material sciences, catalysis, medicinal chemistry, and diagnostic applications. The ferrocene moiety can potentially serve many purposes in therapeutics and diagnostics. In the course of this study, (6-bromo-1-oxohexyl)ferrocene was combined with dimercaptomaleonitrile sodium salt to yield a novel maleonitrile derivative. Subsequently, this compound was subjected to an autocyclotetramerization reaction using the Linstead conditions in order to obtain an octaferrocenyl-substituted magnesium(II) sulfanyl porphyrazine. Following that, both compounds-the maleonitrile derivative and the porphyrazine derivative-were subjected to physicochemical characterization using UV-Vis, ES-TOF, MALDI-TOF, and one-dimensional and two-dimensional NMR spectroscopy. Moreover, the sulfanyl porphyrazine was subjected to various photophysical studies, including optical absorption and emission measurements, as well as the evaluation of its photochemical properties. Values of singlet oxygen generation quantum yields were obtained in different organic solvents. The electrochemical properties of the synthesized compounds were studied using cyclic voltammetry. According to the electrochemical results, the presence of electron-withdrawing oxohexyl groups attached to ferrocene afforded significantly more positive oxidation potentials of the ferrocene-based redox process up to 0.34 V vs. Fc⁺/Fc.

Design, synthesis, in vitro and in silico evaluation of anti-colorectal cancer activity of curcumin analogues containing 1,3-diphenyl-1H-pyrazole targeting EGFR tyrosine kinase

Recent studies have shown that monocarbonyl analogues of curcumin (MACs) and 1H-pyrazole heterocycle both demonstrated promising anticancer activities, in which several compounds containing these scaffolds could target EGFR. In this research, 24 curcumin analogues containing 1H-pyrazole (a1-f4) were synthesized and characterized by using modern spectroscopic techniques. Firstly, synthetic MACs were screened for cytotoxicity against human cancer cell lines such as SW480, MDA-MB-231 and A549, from which the 10 most potential cytotoxic compounds were identified and selected. Subsequently, the selected MACs were further screened for their inhibition against tyrosine kinases, which showed that a4 demonstrated the most significant inhibitory effects on EGFR^WT and EGFR^L858R. Based on the results, a4 further demonstrated its ability to cause morphological changes, to increase the percentage of apoptotic cells, and to increase caspase-3 activity, suggesting its apoptosis-inducing activity on SW480 cells. In addition, the effect of a4 on the SW480 cell cycle revealed its ability to arrest SW480 cells at G₂/M phase. In subsequent computer-based assessments, a4 was predicted to possess several promising physicochemical, pharmacokinetic, and toxicological properties. Via molecular docking and molecular dynamics simulation, a reversible binding mode between a4 and EGFR^WT, EGFR^L858R, or EGFR^G719S, remained stable within the 100-ns simulation due to effective interactions especially the hydrogen bonding with M793. Finally, free binding energy calculations suggested that a4 could inhibit the activity of EGFR^G719S more effectively than other EGFR forms. In conclusion, our work would provide the basis for the future design of promising synthetic compounds as anticancer agents targeting EGFR tyrosine kinase.

Synthesis, Biological Evaluation, and Molecular Modeling Studies of 1-Aryl-1H-pyrazole-Fused Curcumin Analogues as Anticancer Agents

Addressing the growing burden of cancer and the shortcomings of chemotherapy in cancer treatment are the current research goals. Research to overcome the limitations of curcumin and to improve its anticancer activity via its heterocycle-fused monocarbonyl analogues (MACs) has immense potential. In this study, 32 asymmetric MACs fused with 1-aryl-1H-pyrazole (7a-10h) were synthesized and characterized to develop new curcumin analogues. Subsequently, via initial screening for cytotoxic activity, nine compounds exhibited potential growth inhibition against MDA-MB-231 (IC₅₀ 2.43-7.84 μM) and HepG2 (IC₅₀ 4.98-14.65 μM), in which seven compounds showing higher selectivities on two cancer cell lines than the noncancerous LLC-PK1 were selected for cell-free in vitro screening for effects on microtubule assembly activity. Among those, compounds 7d, 7h, and 10c showed effective inhibitions of microtubule assembly at 20.0 μM (40.76-52.03%), indicating that they could act as microtubule-destabilizing agents. From the screening results, three most potential compounds, 7d, 7h, and 10c, were selected for further evaluation of cellular effects on breast cancer MDA-MB-231 cells. The apoptosis-inducing study indicated that these three compounds could cause morphological changes at 1.0 μM and could enhance caspase-3 activity (1.33-1.57 times) at 10.0 μM in MDA-MB-231 cells, confirming their apoptosis-inducing activities. Additionally, in cell cycle analysis, compounds 7d and 7h at 2.5 μM and 10c at 5.0 μM also arrested MDA-MB-231 cells in the G₂/M phase. Finally, the results from in silico studies revealed that the predicted absorption, distribution, metabolism, excretion, and the toxicity (ADMET) profile of the most potent MACs might have several advantages in addition to potential disadvantages, and compound 7h could bind into (ΔG -10.08 kcal·mol^-1) and access wider space at the colchicine-binding site (CBS) than that of colchicine or nocodazole via molecular docking studies. In conclusion, our study serves as a basis for the design of promising synthetic compounds as anticancer agents in the future.

A cascade reaction for regioselective construction of pyrazole-containing aliphatic sulfonyl fluorides

A copper-catalyzed cascade reaction of α-diazocarbonyl compounds with ethenesulfonyl fluoride (ESF) is developed, affording a variety of highly functionalized pyrazolyl aliphatic sulfonyl fluorides in good to excellent yields (66-98%). This transformation features broad substrates, exclusive regioselectivity, high atom economy and operational simplicity, thus providing a straightforward method for the direct construction of pyrazole-containing aliphatic sulfonyl fluorides, which will provide great applicable value in medicinal chemistry and other related disciplines.

An experimental and computational study of new spiro-barbituric acid pyrazoline scaffolds: restricted rotation vs. annular tautomerism

A regioselective [3+2] cycloaddition (32CA) reaction to synthesize unsymmetric spiro-barbituric pyrazolines containing a chromone or phenolic pyrazole moiety was achieved, providing good to excellent yields.

An ultrasound-assisted solvent and catalyst-free synthesis of structurally diverse pyrazole centered 1,5-disubstituted tetrazoles via one-pot four-component reaction

Abstract:

1,5-Disubstituted tetrazoles are vital drug-like scaffold usually encountered as valuable bioisosteres of cis-amide bond. In this article, we reported synthesis of some novel medicinally relevant pyrazole centered 1,5-disubstituted tetrazoles using ultrasound irradiation via a one-pot 4-C reaction from various pyrazole originated aldehyde, amine, isocyanide, and sodium azide. All the synthesized derivatives were characterized by IR, 1H NMR, 13C NMR, spectroscopic techniques, and mass analysis. This ultrasound-assisted green protocol has several advantages like mild reaction condition, high yield, catalyst and solvent-free reaction protocol, 15 minutes reaction time and easy workup.

Crystal structure and Hirshfeld surface analysis study of (E)-1-(4-chloro-phen-yl)-N-(4-ferrocenylphen-yl)methanimine

The substituted cyclo-penta-dienyl ring in the title mol-ecule, [Fe(C5H5)(C18H13ClN)], is nearly coplanar with the phenyl-1-(4-chloro-phen-yl)methanimine substituent, with dihedral angles between the planes of the phenyl-ene ring and the Cp and 4-(chloro-phen-yl)methanimine units of 7.87 (19) and 9.23 (10)°, respectively. The unsubstituted cyclo-penta-dienyl ring is rotationally disordered, the occupancy ratio for the two orientations refined to a 0.666 (7)/0.334 (7) ratio. In the crystal, the mol-ecules pack in 'bilayers' parallel to the ab plane with the ferrocenyl groups on the outer faces and the substituents directed towards the regions between them. The ferrocenyl groups are linked by C-H⋯π(ring) inter-actions. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (46.1%), H⋯C/C⋯ H (35.4%) and H⋯Cl/Cl⋯H (13.8%) inter-actions. Thus C-H⋯π(ring) and van der Waals inter-actions are the dominant inter-actions in the crystal packing.

Efficient synthesis and antitumor evaluation of 4-aminomethyl-N-arylpyrazoles: Discovery of potent and selective agents for ovarian cancer

A new one-pot two-step sequential methodology for synthesis of novel 3-carboxyethyl 4-[(tert-butylamino)methyl]-N-arylpyrazole derivatives is reported. One-pot transformation of β-enamino diketones and arylhydrazines generated 4-iminium-N-arylpyrazole salt intermediates in situ, which were easily transformed into 4-[(tert-butylamino)methyl]-N-arylpyrazole derivatives by NaBH₃CN. The products could be isolated in the free or hydrochloride salt forms. Also, it was possible to obtain the products in the zwitterionic form by ester group hydrolysis. Furthermore, all synthesised compounds were evaluated in vitro against a panel of eight human tumor cell lines. The 4-[(tert-butylamino)methyl]-N-arylpyrazole derivatives were much more powerful than the hydrochloride and zwitterionic forms. Moreover, the results suggest that the N-aryl group at the pyrazole ring is vital for modulating antiproliferative activity. The 3-carboxyethyl 4-[(tert-butylamino)methyl]-N-phenylpyrazoles 3a-g exhibited higher inhibitory activities against OVCAR-3, with GI₅₀ values of 0.013-8.78 μM, and lower inhibitory activities against normal human cell lines. Molecular docking was performed to evaluate the probable binding mode of 3a into active site of CDK2.

Synthesis, Characterization, and Electrochemistry of Diferrocenyl β-Diketones, -Diketonates, and Pyrazoles

The synthesis of FcC(O)CH(R)C(O)Fc (Fc = Fe(η⁵-C₅H₄)(η⁵-C₅H₅); R = H, 5; ⁿBu, 7; CH₂CH₂(OCH₂CH₂)₂OMe, 9), [M(κ²O,O′-FcC(O)CHC(O)Fc)_n] (M = Ti, n = 3, 10; M = Fe, n = 3, 11; M = BF₂, n = 1, 12), and 1-R′-3,5-Fc₂-^cC₃HN₂ (R′ = H, 13; Me, 14; Ph, 15) is discussed. The solid-state structures of 5, 7, 9, 12, 13, 15, and 16 ([TiCl₂(κ²O,O′-PhC(O)CHC(O)Ph)₂]) show that 7 and 9 exist in their β-diketo form. Compound 13 crystallizes as a tetramer based on a hydrogen bond pattern, including one central water molecule. The electrochemical behavior of 5–7 and 9–16 was studied by cyclic and square-wave voltammetry, showing that the ferrocenyls can separately be oxidized reversibly between −50 and 750 mV (5–7, 9, 12–15: two Fc-related events; 10, 11: six events, being partially superimposed). For complex 10, Ti-centered reversible redox processes appear at −985 (Ti^II/Ti^III) and −520 mV (Ti^III/Ti^IV). Spectro-electrochemical UV-Vis/NIR measurements were carried out on 5, 6, and 12, whereby only 12 showed an IVCT (intervalence charge-transfer) band of considerable strength (ν_max = 6250 cm⁻¹, Δν_½ = 4725 cm⁻¹, ε_max = 240 L·mol⁻¹·cm⁻¹), due to the rigid C₃O₂B cycle, enlarging the coupling strength between the Fc groups.

Perspectives of ferrocenyl chalcones: synthetic scaffolds toward biomedical and materials science applications

Ferrocene and its derivatives constitute versatile and interesting scaffolds for the global chemical enterprise due to its multiple applications that range from biomedical to materials science. Ferrocenyl derivatives are the leading compounds in our research for the syntheses and characterization as well as their potential biological applications. Among them, our recent focus has been in ferrocenyl chalcones as a framework for further derivatization. The proposed modifications consist on the incorporation of heterocyclic moieties into the ferrocenyl chalcone core. This can be afforded either by introducing a heterocyclic aromatic moiety as a substituent or functionalizing the α-β unsaturated system. Another modification explored is the formation of ammonium or pyridinium salts to increase water solubility. Studied ferrocenyl chalcones exhibit remarkable stability, physical, and electrochemical properties. These factors have led the approaches for them to be precursors of biologically active compounds (cancer, bacteria, malaria, and neurobiological diseases). Moreover, other potential applications include molecular materials, redox-sensors, and polymers. Our goal in this mini review is to highlight the chemistry of ferrocene derivatives with particular prominence to those ferrocenyl chalcones studied in our laboratory and their applications. Moreover, we are providing a background on ferrocene, chalcones, and ferrocenyl chalcones, emphasizing the methodologies with preeminent yields.

A novel pseudo six-component synthesis of functionalized pyrazoles in ethanol by cascade reaction

Novel-substituted pyrazoles were synthesized using an aminal-based approach. The key steps in the synthetic strategy involve the formation of 1,1-dihydrazino-2-nitroethylene from hydrazine hydrate with nitro ketene dithioacetal and its reaction with Knoevenagel adduct derived from the corresponding aldehyde and malononitrile in ethanol media. The formation of 5-membered pyrazole ring is confirmed based on the electrostatic surface potential computed by density functional theory. This strategy can provide a concise and eco-friendly route for easy access to the highly substituted pyrazoles derivatives in excellent yields using four simple and readily available building blocks under mild conditions and particularly attractive due to features such as atom economy, high yield and mild condition.

Chemo-, Regio-, and Stereoselective N-Alkenylation of Pyrazoles/Benzpyrazoles Using Activated and Unactivated Alkynes

Transition-metal-free chemo-, regio-, and stereoselective synthesis of (Z) and (E) styryl pyrazoles and benzpyrazoles by the addition of N-heterocycles onto functionalized terminal and internal alkynes using a super basic solution of KOH/DMSO has been described. The stereochemical outcome of the reaction was governed by time and quantity of the base. The reaction of pyrazoles and benzpyrazoles onto alkynes takes place chemoselectively without affecting the free -NH₂ group of pyrazoles and -OH group of alkynes. The designed protocol was well implemented on alkynes bearing long alkyl chain, an alicyclic ring, hydroxy, ether, and ester functionality, which offer the N-alkenylated products in good yields. This developed methodology also provides easy access for the synthesis of bis-vinylated heterocycles. The presence of free -NH₂, -OH, -COOR, and halo group in styryl pyrazoles, could be further utilized for synthetic elaboration, which is advantageous for biological evaluation. For the first time, we have disclosed the base-mediated conversion of (Z)-styryl pyrazoles to (E)-styryl pyrazoles in KOH/DMSO system. The cis-trans isomerization was supported by the control experiments and deuterium labeling studies.

Cytotoxic and Antimicrobial Activity of Dehydrozingerone based Cyclopropyl Derivatives

A small series of 1-acetyl-2-(4-alkoxy-3-methoxyphenyl)cyclopropanes was prepared, starting from dehydrozingerone (4-(4-hydroxy-3-methoxyphenyl)-3-buten-2-one) and its O-alkyl derivatives. Their microbiological activities toward some strains of bacteria and fungi were tested, as well as their in vitro cytotoxic activity against some cancer cell lines (HeLa, LS174 and A549). All synthesized compounds showed significant antimicrobial activity and expressed cytotoxic activity against tested carcinoma cell lines, but they showed no significant influence on normal cell line (MRC5). Butyl derivative is the most active on HeLa cells (IC₅₀ = 8.63 μm), while benzyl one is active against LS174 and A549 cell lines (IC₅₀ = 10.17 and 12.15 μm, respectively).

Urea/thiourea: efficient, inexpensive and reusable catalysts for the synthesis of pyrazole derivatives with 2-iminothiazolidin-4-one and 2,4-thiazolidinediones under solvent-free conditions

An efficient and green synthesis of pyrazolyl-2,4-thiazolidinediones/pyrazolyl-2-iminothiazolidine-4-ones 7(a-j) has been developed using urea/thiourea as catalyst. Two methods (A and B) have been introduced for the synthesis of these compounds. Method A performed well for the condensation of pyrazole-4-carboxaldehydes 4(a-e) with 2-iminothiazolidin-4-one 5a and with 2,4-thiazolidinedione 5b at 110 [Formula: see text] for 16-20 min to furnish (Z)-5-((1,3-diphenyl-1H-pyrazol-4-yl)methylene)thiazolidine-2,4-diones 7(a-j) in excellent yields. In method B, the pyrazole-4-carboxaldehydes 4(a-e) were condensed with urea/thiourea at 110 [Formula: see text] for 10 min to give key intermediates 6(a-j) which were later condensed with 5a and 5b to afford 7(a-j) via the elimination of urea/thiourea rather than the formation of a Biginelli product. These two protocols are inexpensive, eco-friendly and high yielding to provide the final products. The synthesis of compound 7f.

Facile synthesis, crystal structure and bioactivity evaluation of two novel barium complexes based on 2,4,6-trichlorophenoxyacetic acid and o-ferrocenylcarbonyl benzoic acid

With a microwave method, two novel Ba(ii) complexes were synthesized for the first time and their allelopathic and antifungal activity was evaluated.

Ferrocenyl based pyrazoline derivatives with vanillic core: synthesis and investigation of their biological properties

Synthesis of four novel series of ferrocenyl based pyrazoline derivatives with vanillic core are described and microbiological, BSA and DNA binding studies conducted.