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This mini‐review focuses on recent developments in hydroxamate‐based metal–organic frameworks (MOFs), which exhibit unique structures and properties distinct from those of carboxylate‐based MOFs. Hydroxamates (RCONHO−) form MOFs with novel structural motifs and functionalities. In this review, synthetic strategies, structural characteristics, and functional applications of key examples of hydroxamate‐based MOFs are described, providing insights into the influence of the hydroxamate ligand on the MOF properties compared to that of the carboxylate‐based analogues. [ABSTRACT FROM AUTHOR]

Abstract Hydroxamic acids represent a group of weak organic acids, both naturally occurring and synthetically derived, characterized by the general formula RC(= O)N(R’OH). In this study, we investigated the binding behavior of N-m-tolyl-4-chlorophenoxyaceto hydroxamic acid with calf thymus DNA (ct-DNA) and torula yeast RNA (t-RNA) through a combination of techniques including UV–visible spectroscopy, fluorescence emission analysis, viscometry, and computational simulations using AutoDock4 software. Our findings reveal that the mode of binding between the compound and the nucleic acids is consistent with intercalation. Competitive binding experiments demonstrated that the complex competes effectively with ethidium bromide (EB) for binding to ct-DNA/t-RNA, displacing EB from its binding sites. Additionally, the introduction of the compound into the DNA-EB system resulted in a quenching of fluorescence emission peaks. Analysis of absorption spectra indicated a red shift and hypochromic shift when the compound interacted with DNA, further supporting the intercalative binding mode. The calculated binding constant (Kb) value for the compound is 6.62 × 104 M−1 and 5.40 × 103 M−1 indicating a strong interaction with ct-DNA and t-RNA respectively. We determined the Stern–Volmer constants for ct-DNA and t-RNA as 9.96 × 104 M−1 and 8.13 × 105 M−1, respectively. The binding free energy values for ct-DNA/t-RNA were calculated to be − 3.741 × 107 and − 5.425 × 108 kcal/mol, respectively. Viscometric studies corroborated the UV results, showing a continuous increase in relative viscosity of ct-DNA/t-RNA solutions with the addition of the optimal hydroxamic acid concentration. Furthermore, we assessed the antioxidant activity of the compound using DPPH-radical scavenging and β-carotene linoleic acid assays. Gel electrophoresis results demonstrated the compound's remarkable efficacy in preventing DNA damage. Collectively, all experimental evidence supports the conclusion that N-m-tolyl-4-chlorophenoxyaceto hydroxamic acid binds to ct-DNA/t-RNA through an intercalative mechanism, which is consistent with our molecular docking simulations.

Due to the high abundance and diverse functions of lysine residues, both in the interior and on the surface of proteins, the development of new methods to characterize their reactivity and ligandability could significantly expand the pool of druggable targets. To date, only a limited number of aminophilic electrophiles have been assessed for interactions with the lysine proteome, resulting in a substantial fraction remaining inaccessible to current probes. Here, to the best of our knowledge, we report the first oxidant‐triggered bioconjugation platform for in‐depth profiling of lysines. We quantified over 7000 covalently modifiable lysine residues, which significantly expands the coverage of ligandable lysines in the whole proteome. Chemical proteomics enabled the mapping of more than 100 endogenous kinases, thus providing a comprehensive landscape of ligandable catalytic lysines within the kinome. Moreover, we identified a suite of new ligandable lysines such as K60 of ENO1 and K31 of PPIA, offering insights for exploring new functional and targetable residues. These findings could provide valuable clues for the development of targeted covalent inhibitors (TCIs). [ABSTRACT FROM AUTHOR]

In the present work, we performed a computational study on hydroxamic acid containing compounds as acid sphingomyelinase (ASM) inhibitors. The study starts from the development of 3D‐QSAR and pharmacophore models, which were further taken as a source for the enumeration and virtual screening study. The 3D‐QSAR results showed the best statistical model with Q2, R2, and R2 scrambling values of 0.7175, 0.9019, and 0.7128, respectively. The pharmacophore hypothesis generated one of the best hypotheses including five features such as 2 aromatic rings, 2 hydrogen bond donors, and 1 hydrogen bond acceptor. The enumeration study paved the path in the discovery of novel compounds where pharmacophore hypothesis and 3D QSAR study data was used for the identification of novel compounds. Compound 9f_20 showed good docking score −11.399 and binding interactions with amino acids HIP317, ASN316, GLH386, Zn701, Zn702, HIP317, and HIP280 required for ASM inhibitory activity. The virtual screening study was performed on the basis of developed pharmacophore ADDRR_1 where ZINC000013941849 showed good binding interactions with receptor including amino acids Zn701, Zn702, HIP280, LYS103, HIP317, ASN316, and ILE487. ZINC000013941849 with docking score −13.101. The screened compounds may be taken for the further development of novel antidepressant agents. [ABSTRACT FROM AUTHOR]

In order to better understand the liquid crystalline behavior of recently synthesized metal hydroxamates, optical microscopy and differential scanning calorimetry have been employed. Analysis of their thermal stability and loss of mass by thermogravimetry and differential thermal analysis has been performed. The nematic mesophase can be observed in nearly all metal hydroxamates, with the exception of N-4-isopropoxyphenyl-4'-n-butoxycinnamohydroxamic acid complexes and iron hydroxamic acid complexes. Copper(II) hydroxamate complexes of N-4-n-butoxyphenyl-4'-n-butoxycinnamo hydroxamic acid and N-4-isoamyloxyphenyl-4'-n-butoxycinnamohydroxamic acid exhibit nematic as well as smectic behavior. [ABSTRACT FROM AUTHOR]

Hydroxamic acids represent a group of weak organic acids, both naturally occurring and synthetically derived, characterized by the general formula RC(= O)N(R'OH). In this study, we investigated the binding behavior of N-m-tolyl-4-chlorophenoxyaceto hydroxamic acid with calf thymus DNA (ct-DNA) and torula yeast RNA (t-RNA) through a combination of techniques including UV–visible spectroscopy, fluorescence emission analysis, viscometry, and computational simulations using AutoDock4 software. Our findings reveal that the mode of binding between the compound and the nucleic acids is consistent with intercalation. Competitive binding experiments demonstrated that the complex competes effectively with ethidium bromide (EB) for binding to ct-DNA/t-RNA, displacing EB from its binding sites. Additionally, the introduction of the compound into the DNA-EB system resulted in a quenching of fluorescence emission peaks. Analysis of absorption spectra indicated a red shift and hypochromic shift when the compound interacted with DNA, further supporting the intercalative binding mode. The calculated binding constant (Kb) value for the compound is 6.62 × 104 M−1 and 5.40 × 103 M−1 indicating a strong interaction with ct-DNA and t-RNA respectively. We determined the Stern–Volmer constants for ct-DNA and t-RNA as 9.96 × 104 M−1 and 8.13 × 105 M−1, respectively. The binding free energy values for ct-DNA/t-RNA were calculated to be − 3.741 × 107 and − 5.425 × 108 kcal/mol, respectively. Viscometric studies corroborated the UV results, showing a continuous increase in relative viscosity of ct-DNA/t-RNA solutions with the addition of the optimal hydroxamic acid concentration. Furthermore, we assessed the antioxidant activity of the compound using DPPH-radical scavenging and β-carotene linoleic acid assays. Gel electrophoresis results demonstrated the compound's remarkable efficacy in preventing DNA damage. Collectively, all experimental evidence supports the conclusion that N-m-tolyl-4-chlorophenoxyaceto hydroxamic acid binds to ct-DNA/t-RNA through an intercalative mechanism, which is consistent with our molecular docking simulations. [ABSTRACT FROM AUTHOR]

Background Molecular hybridization in drug design is proved to be very successful approach to provide new chemical entities with potential activities and desirable physicochemical properties. Histone deacetylases (HDACs) are involved in controlling the behavior and acetylation of histone and non-histone proteins and their inhibition causes block of cell growth, differentiation, changes in gene expression, and death. Consequently, HDAC inhibitors may lead to anticytotoxic activity. An approach of synthesizing hybrid molecules of benzothiazole cross-linked with hydroxamic acid via an amino acid or aminoalkanoic acid was considered. This approach is expected to optimize the anticytotoxic activity of the proposed compounds. Methods Hybrid molecules of benzothiazole cross-linked with hydroxamic acid ( 2A-E) were synthesized and their chemical structures were confirmed by spectral analyses (FT-IR, 1H-NMR and 13C-NMR). These were subjected to molecular docking on HDAC8 (PDB ID: 1T69). Computational methods were employed using the SwissADME server to predict the ADME parameters and other physicochemical properties. The cytotoxicity evaluation was performed using MTT colorimetric assay. Results Hybrids ( 2A-E) recorded lower ΔG ( -6.322 to - 9.46) than Vorinostat (SAHA, -5.375). ΔG is an affinity scoring function (kcal/mol) and is employed to rank the candidate poses as the sum of the electrostatic and Van der Waals energies. Benzothiazole cross-linked with hydroxamic acid by a p-aminobenzoic acid ( 2E) has recorded the lowest docking score of -9.460 and this may refer to the possibility of high inhibitory activity. The hybrids showed no violation from Lipinski’s rule and complied with parameters with low possible passive oral absorption and no penetration into BBB. Hybrid molecules of benzothiazole recorded very interesting results, particularly, 2D and 2E which showed significant and remarkable activity. Conclusions Hybrid molecules of benzothiazole cross-linked with hydroxamic acid recorded very interesting results, particularly, compounds 2D and 2E which showed significant and remarkable activity on lung cancer cell line type A549.

The pollution of water bodies by heavy metal ions has recently become a global concern. In this experiment, a novel chelating resin, D851-6-AHHA, was synthesized by grafting 6-amino-N-hydroxyhexanamide (6-AHHA) onto the (-CH2N-(CH2COOH)2) group of the D851 resin, which contained a hydroxamic acid group, amide group, and some carboxyl groups. This resin was developed for the purpose of removing heavy metal ions, such as Cr(III) and Pb(II), from water. The findings from static adsorption experiments demonstrated the remarkable adsorption effectiveness of D851-6-AHHA resin towards Cr(III) and Pb(II). Specifically, the maximum adsorption capacities for Cr(III) and Pb(II) were determined to be 91.50 mg/g and 611.92 mg/g, respectively. Furthermore, the adsorption kinetics of heavy metal ions by D851-6-AHHA resin followed the quasi-second-order kinetic model, while the adsorption isotherms followed the Langmuir model. These findings suggest that the adsorption process was characterized by monolayer chemisorption. The adsorption mechanism of D851-6-AHHA resin was comprehensively investigated through SEM, XRD, FT-IR, and XPS analyses, revealing a high efficiency of D851-6-AHHA resin in adsorbing Cr(III) and Pb(II). Specifically, the (-C(=O)NHOH) group exhibited a notable affinity for Cr(III) and Pb(II), forming stable multi-elemental ring structures with them. Additionally, dynamic adsorption experiments conducted using fixed-bed setups further validated the effectiveness of D851-6-AHHA resin in removing heavy metal ions from aqueous solutions. In conclusion, the experimental findings underscored the efficacy of D851-6-AHHA resin as a highly efficient adsorbent for remediating water bodies contaminated by heavy metal ions. [ABSTRACT FROM AUTHOR]

A one-step synthesis of 5-isothiocyanato-6-methyluracil from the corresponding hydroxamic acid was carried out. A plausible mechanism of the reaction was proposed. [ABSTRACT FROM AUTHOR]

Background The influenza virus is a highly contagious respiratory disease that causes seasonal outbreaks and occasionally, unpredictable pandemics with high morbidity and mortality rates. This problem is exacerbated by the lack of drugs with potential antiviral activity against all types of influenza strains, including resistant strains. Therefore, there is an urgent need to develop novel antiviral agents. Methods The synthesis of new oseltamivir carboxamides with amino acids and the subsequent synthesis of hybrid molecules with hydroxamic acid were considered. Two series are presented as series one; oseltamivir carboxamides with L-serine, L-isoleucine, L-phenylalanine, L-tyrosine and series two included hydroxamates of series one. This approach may provide promising candidates with potential anti-influenza activity. The in vitro cytotoxic activity against Madin-Darby Canine Kidney (MDCK), type (NBL-2) - CCL-34 cells using the MTT ((3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to determine the half maximal inhibitory concentrations (IC 50) of the investigated compounds. The percent inhibition of neuraminidase was plotted against concentrations and the IC 50 values were calculated by non-linear logistic curve fitting. Results The compounds were subjected to molecular docking using the GOLD suite (version 5.7.1) to predict the binding affinities for neuraminidase (3CL0). The docking scores are presented as PLP fitness and are comparable to those of oseltamivir. Oseltamivir-Phenylalanine recorded the highest docking score (72.23 kcal/mol), while, oseltamivir acid was recorded (56.24 kcal/mol). The ADMET parameters were generated using the Swiss ADME server to predict successful candidates with reasonable oral absorption and safety margins. All compounds are safer than oseltamivir and their IC 50 values for neuraminidase inhibition were variable. The hybrids showed a lower percentage of viable cells. Oseltamivir-phenylalanine had the highest inhibitory activity against neuraminidase (3.03 μM), when compared with oseltamivir (67.22 μM). Conclusion Oseltamivir-phenylalanine showed remarkable and very significant activity, and the hybrid molecules were surprisingly less effective on neuraminidase than oseltamivir carboxamides.

A novel method for extraction, separation, and trace determination of thorium(IV) with calix[4]resorcinarene-2, 8, 14, 20-tetrakis[N-phenylbenzo]-hydroxamic acid (C4RATHA) is described. The thorium (IV) is extracted from an n-octanol solution of C4RATHA at a pH of 4.5, as colorless extract with a maximum absorption at 375 nm and molar absorptivity of 1.5 × 104 L mol−1 cm−1. The extract is then analyzed using ICP-AES, and a linear calibration graph is obtained between 35.88 and 309.40 ng mL−1 with a detection limit of 20 ng mL−1. The method is applied be used to measure thorium (IV) in monazite sand and rare earth sand in the presence of other diverse ions. The thorium is recovered from seawater and analyzed. [ABSTRACT FROM AUTHOR]

Herein, we report triflic anhydride mediated synthesis of ureas starting from hydroxamic acids. The scope of triflic anhydride was also expanded to encompass carbamates. In addition, this reaction is applicable to activation of hydroxamic acid derivative of dipeptide giving α‐uriedopeptidomimetics in good yield. The mechanistic study of reaction was carried out by DFT. This study is important because it demonstrates that Tf2O has the potential to be effective when used on a substrate that possesses amide bond. A broad substrate scope and mild conditions render this protocol a promising approach to the synthesis of diverse types of ureas. [ABSTRACT FROM AUTHOR]

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The efficient development of selective materials for uranium recovery from wastewater and seawater is crucial for the utilization of uranium resources and environmental protection. The potential of graphene oxide (GO) as an effective adsorbent for the removal of environmental contaminants has been extensively investigated. Further modification of the functional groups on the basal surface of GO can significantly enhance its adsorption performance. In this study, a novel poly(amidoxime-hydroxamic acid) functionalized graphene oxide (pAHA-GO) was synthesized via free radical polymerization followed by an oximation reaction, aiming to enhance its adsorption efficiency for U(VI). A variety of characterization techniques, including SEM, Raman spectroscopy, FT–IR, and XPS, were employed to demonstrate the successful decoration of amidoxime and hydroxamic acid functional groups onto GO. Meanwhile, the adsorption of U(VI) on pAHA-GO was studied as a function of contact time, adsorbent dosage, pH, ionic strength, initial U(VI) concentration, and interfering ions by batch-type experiments. The results indicated that the pAHA-GO exhibited excellent reuse capability, high stability, and anti-interference ability. Specially, the U(VI) adsorption reactions were consistent with pseudo-second-order and Langmuir isothermal adsorption models. The maximum U(VI) adsorption capacity was evaluated to be 178.7 mg/g at pH 3.6, displaying a higher U(VI) removal efficiency compared with other GO-based adsorbents in similar conditions. Regeneration of pAHA-GO did not significantly influence the adsorption towards U(VI) for up to four sequential cycles. In addition, pAHA-GO demonstrated good adsorption capacity stability when it was immersed in HNO3 solution at different concentrations (0.1–1.0 mol/L) for 72 h. pAHA-GO was also found to have anti-interference ability for U(VI) adsorption in seawater with high salt content at near-neutral pH condition. In simulated seawater, the adsorption efficiency was above 94% for U(VI) across various initial concentrations. The comprehensive characterization results demonstrated the involvement of oxygen- and nitrogen-containing functional groups in pAHA-GO in the adsorption process of U(VI). Overall, these findings demonstrate the feasibility of the pAHA-GO composite used for the capture of U(VI) from aqueous solutions. [ABSTRACT FROM AUTHOR]

In recent years, biocatalysts have emerged as crucial tool in organic synthesis, particularly for the production of drug intermediates and precursors, e.g., the synthesis of hydroxamic acids. Traditionally, hydroxamic acids were synthesized using organic chemistry methods. However, with the growing emphasis on sustainable and environment‐friendly practices, the chemical industry has increasingly turned towards green synthesis approaches. The significance of hydroxamic acids in medicinal chemistry has also contributed to the changing trends. Following the approval of certain hydroxamic acids as histone deacetylase (HDAC) inhibitors for cancer treatment by the Food and Drug Administration (US‐FDA), there has been a renewed focus on their synthesis and the development of derivatives with improved properties. As an alternative route, amidases have emerged as promising biocatalysts for hydroxamic acid synthesis through their acyltransferase activity. Recent advancements in the synthesis approaches for hydroxamic acids are reviewed. The biocatalytic routes are explored, emphasizing the use of amidases and their acyltransferase activity. The scope and potential applications of this chemoenzymatic approach in synthesizing various hydroxamic acids and their derivatives are discussed. Such advancements have the potential to revolutionize the production of these important compounds, making the synthesis process more sustainable, efficient, and economically viable. [ABSTRACT FROM AUTHOR]

The investigation of thermoluminescence (TL) glow curves in liquid crystalline side chain N‐phenyl‐substituted phenyl polysiloxane hydroxamic acids (PHAs) has yielded significant insights. These polymers demonstrated TL behavior when exposed to β‐radiation between 0 and 220°C, indicating inherent luminescent properties when irradiated. Notably, a dose‐dependent relationship was observed in reported derivatized polymers; this study elucidates the diverse TL characteristics exhibited by various liquid crystalline side chain N‐phenyl‐substituted phenyl PHAs when exposed to β‐radiation. Understanding these dose‐dependent and dose‐independent behaviors enhances the knowledge of their luminescent properties and potential applications in radiation detection. [ABSTRACT FROM AUTHOR]

Histone deacetylase inhibitors (HDACIs) represent a well-known class of compounds that exhibit potential therapeutic efficacy in a variety of diseases, particularly cancer and neurodegenerative disorders. This article discusses the development of compound 6 as a new HDAC inhibitor. It was designed based on the structure activity relationship (SAR) of the previously reported HDAC inhibitors and the molecular modeling studies. Compound 6 was synthesized, and its structure was verified using different spectroscopic methods. It was biologically evaluated to assess its inhibitory activity against different HDAC isoforms, including HDAC1, 6, and 8. The results showed moderate inhibition against HDAC 1 and HDAC 8 over HDAC 6. It was also evaluated for its antineoplastic activity against the NCI 60 cancer cell line panel. The results revealed inhibitory activity against both the UO-31 renal cancer cell line and the BT-549 breast cancer cell line. Moreover, the Molecular modeling studies revealed favorable binding affinity for the HDAC8 active site. These results suggest that compound 6 can be considered as a promising candidate for the development of new selective class I HDACIs in the future.

This study involved the development of innovative compounds consisting of dipeptide cross-links combined with hydroxamic acid. Our objective was to assess their binding affinities with histone deacetylase 8 (HDAC8) by conducting a docking study, comparing the results with the reference ligand, suberoylanilide hydroxamic acid (SAHA). Docking scores were measured in terms of ΔG (Kcal/mol), and the recorded scores for compounds 2A-D were found to be higher than that of SAHA, with values of 87.36, 80.46, 79.42, and 74.14, respectively. Notably, compound 2A, a dipeptide consisting of L-tryptophyl-L-tyrosine linked to a hydroxamic acid moiety, exhibited the highest docking score of 87.36. This finding suggests that compound 2A may possess the most potent HDAC8 inhibitory activity among the other designed compounds. Furthermore, we utilized the SwissADME server to predict the physicochemical properties and additional ADME parameters for the designed compounds. The analysis revealed that all investigated compounds exhibited a high potential for passive oral absorption and demonstrated no penetration into the blood-brain barrier. Compound 2A, 2B, and 2D exhibited one Lipinski's rule violation each, whereas Compound 2C demonstrated no such violations in all parameters. Additionally, compounds 2A and 2C exhibited potential as P-glycoprotein (P-gp) substrates. SAHA did not exhibit inhibition of any of the cytochrome P450 (CYP) enzymes used in this study, whereas compounds 2B, 2C and 2D displayed possible inhibitory activities. These compelling findings provide encouraging prospects for the future synthesis of the designed compounds and warrant further evaluation through in vitro and in vivo biological studies.

In this study, benzohydroxamic acid molecules were synthesized from methyl 4‐amino‐2‐methoxy, methyl 4‐amino‐3‐nitro, methyl 4‐amino‐3‐methyl, and methyl 4‐amino‐3‐chloro benzoate molecules, and the horseradish peroxidase (HRP) enzyme was purified in one step using the affinity chromatography technique for the first time. The IC50 and Ki values for the 4‐amino 3‐methyl benzohydroxamic acid molecule were 0.136 and 0.132 ± 0.054 μM, respectively, while the IC50 and Ki values for the 4‐amino‐3‐nitro benzohydroxamic acid molecule were 56.00 and 51.90 ± 9.90 μM, respectively. It was found that the IC50 and Ki values for the 4‐amino‐3‐chloro benzohydroxamic acid molecule were 218.33 and 175.67 ± 43.78 μM, respectively, whereas the IC50 and Ki values for the 4‐amino‐2‐methoxy benzohydroxamic acid molecule were 306.00 and 218.00 ± 68.80 μM, respectively. The HRP enzyme was synthesized from 4‐amino‐2‐methoxy hydroxamic acid column with a 35.97% yield 601.13 times, 4‐amino‐3‐nitro hydroxamic acid column, with a 14.00% yield 404.11 times, 4‐amino‐3‐methyl hydroxamic acid column with an 8.70% yield 394.88 times, and 4‐amino‐3‐chloro hydroxamic acid column with a 4.48% yield 284.85 times. Thus, the HRP enzyme was purified in a single step with hydroxamic acids, and its molecular weight was found to be 44 kDa. The optimum pH was 8.0, the optimum temperature was 15°C, and the optimum ionic strength was 0.4 M for the purified HRP enzyme. [ABSTRACT FROM AUTHOR]

Climate change mitigation on a global scale will only be possible through the achievement of ambitious decarbonisation goals, requiring an energy transition that involves switching from fossil fuels to clean fuels such as hydrogen. The photocatalytic approach is one of the most studied methods for directly converting sunlight into hydrogen. In this work, we present the synthesis, characterization, and application of the PTZ1‐HA dye, which was obtained by replacing the terminal conventional carboxylic anchoring moieties of a previously studied phenothiazine‐based dye (PTZ1) with hydroxamic acid functionalities. The photoinduced performance of the two dyes as photosensitizers was compared in both dye‐sensitized solar cells and dye‐sensitized photocatalytic systems. PTZ1‐HA‐sensitized photocatalysts showed improved stability in hydrogen generation due to the introduction of the hydroxamic acid as an alternative anchor group, which was shown to slow down hydrolysis in aqueous media. Even though the light harvesting ability of PTZ1‐HA was lower than that of PTZ1, the higher stability of PTZ1‐HA‐sensitized devices allowed for improved photocatalytic generation of H2 over prolonged periods. The superior long‐term efficiency of the hydroxamic acid based dye is important in view of potential practical applications. [ABSTRACT FROM AUTHOR]

In this paper, using methyl cinnamate as raw material, the new cinnamic hydroxamic acid collector (CIHA) was synthesized by the hydroxylamine method. The collector performance of hydroxamic acid was investigated for scheelite and gangue calcite, and the flotation separation test of scheelite and calcite was carried out with CIHA as the collector. The interaction mechanism between hydroxamic acid and scheelite minerals has also been investigated through zeta potential, Fourier transform infrared spectroscopy (FTIR) experiments, X-ray photoelectron spectroscopy (XPS) experiments, and density functional theory (DFT) calculation. The single mineral flotation test and artificially mixed ore showed that CIHA had an excellent collection effect and selectivity. Zeta potential, FTIR, and XPS showed that CIHA was adsorbed on the scheelite surface by strong chemical adsorption. The active group of CIHA was analyzed through quantum chemical calculation. It was speculated that CO and NO bonds could synthesize a five-membered chelated hydroxamic acid group with Ca element chelate on scheelite surface, changing hydrophobicity and making it more likely to emerge from the pulp.

A novel method for extracting and measuring trace amounts of indium, gallium, and thallium using a synthesized [2]rotaxane hydroxamic acid is proposed. The method involves extracting the elements at specific pH levels using chloroform and measuring them using spectrophotometry and inductively couples plasma atomic emission spectrometry (ICP-AES). The extraction mechanism and the factors that influence the extraction process are also discussed. The method is shown to be effective for measuring these elements in a variety of samples, such as alloys, environmental samples, minerals, water, and biological samples. The sensitivity of this method is enhanced 60 times by ICP-AES measurements, which makes it useful for trace determination of In, Ga, and Tl. [ABSTRACT FROM AUTHOR]

Herein, a novel C=O–NOH-contained compound was synthesized and used in the extraction and recovery of copper from sulfate solution. Dodecyl phenyl ethyl hydroxamic acid (DPEHA) exhibited high selectivity to Cu(II) over the competing ions, and the separation factors (β) obtained were βCu/Zn = 227.370, βCu/Co = 199.094, βCu/Ni = 188.889, respectively. The separation effect was stronger than that of 2-hydroxy-5-nonyl acetophenone oxime. Meanwhile, extraction capacity of 0.10 g Cu(II) per gram DPEHA was reached, and the extracted Cu(II) can be stripped effectively. The investigation of extraction mechanism revealed that O atoms in C=O and O-H groups of DPEHA operate as active sites, which could powerfully chelate with Cu(II) by forming stable five-membered rings. The high copper extraction efficiency and selectivity associated with a simple synthesis of DPEHA make it to serve as the potential selective Cu(II) extractant, which also provide a novel insight for the research and development of economical Cu(II) extractants. [ABSTRACT FROM AUTHOR]

Herein, we develop a metal catalyst‐free protocol for O‐arylation of benzamide hydroxamate esters. The chemoselective O‐ versus N‐arylation of the amides was tuned by varying the electronic and/or steric properties of the diaryliodonium salt and/or the substrate. The O‐arylation reaction would preferentially occur for sterically and electronically diverse substrates. This study, which reveals the possibility of substituent‐ and reagent‐controlled chemoselectivity, with diaryliodonium salts might attract interest in the area of hypervalent iodine chemistry. [ABSTRACT FROM AUTHOR]

The limited therapeutic options for fungal infections and the increased incidence of fungal strains resistant to antifungal drugs, especially Candida spp. require the development of new antifungal drugs and strategies. Histone deacetylase inhibitors (HDACi), like vorinostat, have been studied in cancer treatment and have antifungal effects, acting alone or synergistically with classical antifungals. Here we investigated the antifungal activity of two novel sustainable HDACi (LDT compounds) based on vorinostat structure. Molecular docking simulation studies reveal that LDT compounds can bind to Class-I HDACs of Candida albicans, C. tropicalis , and Cryptococcus neoformans , which showed similar binding mode to vorinostat. LDT compounds showed moderate activity when tested alone against fungi but act synergistically with antifungal azoles against Candida spp. They reduced biofilm formation by more than 50% in C. albicans (4 µg/mL), with the main action in fungal filamentation. Cytotoxicity of the LDT compounds against RAW264.7 cells was evaluated and LDT536 demonstrated cytotoxicity only at the concentration of 200 µmol/L, while LDT537 showed IC50 values of 29.12 µmol/L. Our data indicated that these sustainable and inexpensive HDACi have potential antifungal and antibiofilm activities, with better results than vorinostat, although further studies are necessary to better understand the mechanism against fungal cells. [ABSTRACT FROM AUTHOR]

Superparamagnetic iron oxide nanoparticles (SPION) with a "non-fouling" surface represent a versatile group of biocompatible nanomaterials valuable for medical diagnostics, including oncology. In our study we present a synthesis of novel maghemite (γ-Fe2O3) nanoparticles with positive and negative overall surface charge and their coating by copolymer P(HPMA-co-HAO) prepared by RAFT (reversible addition–fragmentation chain-transfer) copolymerization of N-(2-hydroxypropyl)methacrylamide (HPMA) with N-[2-(hydroxyamino)-2-oxo-ethyl]-2-methyl-prop-2-enamide (HAO). Coating was realized via hydroxamic acid groups of the HAO comonomer units with a strong affinity to maghemite. Dynamic light scattering (DLS) demonstrated high colloidal stability of the coated particles in a wide pH range, high ionic strength, and the presence of phosphate buffer (PBS) and serum albumin (BSE). Transmission electron microscopy (TEM) images show a narrow size distribution and spheroid shape. Alternative coatings were prepared by copolymerization of HPMA with methyl 2-(2-methylprop-2-enoylamino)acetate (MMA) and further post-polymerization modification with hydroxamic acid groups, carboxylic acid and primary-amino functionalities. Nevertheless, their colloidal stability was worse in comparison with P(HPMA-co-HAO). Additionally, P(HPMA-co-HAO)-coated nanoparticles were subjected to a bio-distribution study in mice. They were cleared from the blood stream by the liver relatively slowly, and their half-life in the liver depended on their charge; nevertheless, both cationic and anionic particles revealed a much shorter metabolic clearance rate than that of commercially available ferucarbotran. [ABSTRACT FROM AUTHOR]

In this study, we report the development of efficient synthetic strategies for the preparation of novel 2'-carboxyl isoflavones and their recyclization products, pyrazoles and oxazoles. Utilizing readily accessible starting materials and mild reaction conditions, the synthesis affords valuable compounds with good to excellent yields. The presence of diverse functional groups, including hydroxyl, carboxyl, and carboxamido moieties, renders these molecules attractive for biological screening and targeted structural modifications. This work unveils new avenues for the design of compounds exhibiting a wide range of beneficial properties and opens new opportunities for future research into intramolecular interactions of proximal functional groups. [ABSTRACT FROM AUTHOR]

A novel reagent 2,14-bis[m-nitrophenyl]-calix[4]resorcinarene-8,20-bis[N-phenylbenzo]-dihydroxamic acid (NPC4RADHA) is reported for the liquid-liquid extraction, separation, and simultaneous trace determination of La(III), Ce(III), Nd(III), and Gd(III). The method involves optimizing various parameters such as the concentration of NPC4RADHA, pH, solvent, and extraction time to achieve maximum purity (99.98%) extraction of these rare earths. The stability constant, molar absorptivity, and Beer's law have been studied. The extracted samples were directly analyzed by ICP-AES, which improves sensitivity with determination limits of 0.020 ng/mL, 0.028 ng/mL, 0.018 ng/mL and 0.025 ng/mL for La, Ce, Nd, and Gd, respectively. The method has been applied to the determination of these elements in monazite sand and standard geological samples. The separation and determination mixture of a Ce(III) and Ce(IV) has been reported. [ABSTRACT FROM AUTHOR]

A strategy has been developed for the carbon‐14 radiosynthesis of [14C]‐SHP‐141, a 4‐(7‐hydroxycarbamoyl‐heptanoyloxy)‐benzoic acid methyl ester derivative containing a terminal hydroxamic acid. The synthesis involved four radiochemical transformations. The key step in the radiosynthesis was the conversion of the 7‐[14C]‐cyano‐heptanoic acid benzyloxyamide [14C]‐4 directly into the carboxylic acid derivative, 7‐benzyloxycarbamoyl‐[14C]‐heptanoic acid [14C]‐8 using nitrilase‐113 biocatalyst. The final step involved deprotection of the benzyloxy group using catalytic hydrogenation to facilitate the release of the hydroxamic acid without cleaving the phenoxy ester. [14C]‐SHP‐141 was isolated with a radiochemical purity of 90% and a specific activity of 190 μCi/mg from four radiochemical steps starting from potassium [14C]‐cyanide in a radiochemical yield of 45%. [ABSTRACT FROM AUTHOR]

The structure of four hydroxamic acids (HA) that show antifungal activities in complexes with several metals is revealed by single crystal diffraction. The structures of HA with C2, C6, C10, and C12 hydrocarbon chains are reported. The smallest member of the series, N-hydroxyacetamide (HA2), crystallizes in the centrosymmetric space group P21/c while those with longer chain lengths N-hydroxyhexanamide (HA6), N-hydroxydecanamide (HA10), and N-hydroxydodecanamide (HA12) crystallize in the space group P21, and display remarkable packing. [ABSTRACT FROM AUTHOR]

Breast cancer (BC) is the leading cause of cancer-related death in women worldwide. Triple negative breast cancer (TNBC) is the most aggressive form of BC being with the worst prognosis and the worst survival rates. There is no specific pharmacological target for the treatment of TNBC; conventional therapy includes the use of non-specific chemotherapy that generally has a poor prognosis. Therefore, the search of effective therapies against to TNBC continues at both preclinical and clinical level. In this sense, the exploration of different pharmacological targets is a continue task that pave the way to epigenetic modulation using novel small molecules. Lately, the inhibition of histone deacetylases (HDACs) has been explored to treat different BC, including TNBC. HDACs remove the acetyl groups from the ɛ-amino lysine resides on histone and non-histone proteins. In particular, the inhibition of HDAC6 has been suggested to be useful for the treatment of TNBC due to it is overexpressed in TNBC. Therefore, in this work, an HDAC6 selective inhibitor, the (S)-4-butyl-N-(1-(hydroxyamino)-3-(naphthalen-1-yl)-1-oxopropan-2-yl) benzamide (YSL-109), was assayed on TNBC cell line (MDA-MB231) showing an antiproliferative activity (IC50 = 50.34 ± 1.11 µM), whereas on fibroblast, it was lesser toxic. After corroborating the in vitro antiproliferative activity of YSL-109 in TNBC, the toxicological profile was explored using combined approach with in silico tools and experimental assays. YSL-109 shows moderate mutagenic activity on TA-98 strain at 30 and 100 µM in the Ames test, whereas YSL-109 did not show in vivo genotoxicity and its oral acute toxicity (LD50) in CD-1 female mice was higher than 2000 mg/kg, which is in agreement with our in silico predictions. According to these results, YSL-109 represents an interesting compound to be explored for the treatment of TNBC under preclinical in vivo models. [ABSTRACT FROM AUTHOR]

Six‐ and seven‐membered cyclic hydroxamic acids are found as terminal binding units in different families of siderophores, including exochelins and mycobactins. The simplest models of these preorganized chelating ligands were known, but their coordination chemistry with Fe3+, the target metal ion of siderophores, had never been reported. Four complexes were synthesized and studied: two Fe3+ complexes, one with the six‐membered ring hydroxamate PIPO− and one with the seven‐membered ring hydroxamate AZEPO−, and the two corresponding Ga3+ complexes. X‐ray diffraction studies showed that the interligand repulsion energies were better minimized in the case of the AZEPO− complexes whatever the metal cation considered, and that the Fe−O bond distances were shorter in [Fe(AZEPO)3] by comparison with [Fe(PIPO)3]. [ABSTRACT FROM AUTHOR]

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Asymmetric oxidation reaction is one of the significant pathways in stereoselective reactions, which is a prominent performer in academic and industrial research. However, ligands are vital for planning an ideal metal‐catalyzed asymmetric oxidation reaction as they interact with the metal to construct catalytically active metal complexes, which can catalyze numerous asymmetric reactions. Designing and synthesizing novel chiral ligands is essential for researchers in modern asymmetric synthesis. In this course, exploring the applicability and the survey of hydroxamic acid as a vital ligand has been presented, which is essential for various metal‐catalyzed transformations. [ABSTRACT FROM AUTHOR]

We report the design and synthesis of novel hydroxamic acid-tethered organoselenium (OSe) hybrids. Their antimicrobial and anticancer activities were assessed against different microbes (e.g., Candida albicans (C. albicans), Escherichia coli (E. coli), and Staphylococcus aureus (S. aureus)), as well as liver and breast carcinomas. OSe hybrid 8 showed promising anticancer activity, with IC50 = 7.57 ± 0.5 µM against HepG2 and IC50 = 9.86 ± 0.7 µM against MCF-7 cells. Additionally, OSe compounds 8 and 15 exhibited promising antimicrobial activities, particularly against C. albicans (IA% = 91.7 and 83.3) and S. aureus (IA% = 90.5 and 71.4). The minimum inhibitory concentration (MIC) assay confirmed the potential antimicrobial activity of OSe compound 8. OSe compounds 8 and 16 displayed good antioxidant activities compared to vitamin C in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays. These results indicate that hydroxamic acid-based organoselenium hybrids have promising biological activities such as anticancer, antimicrobial, and antioxidant properties, especially compounds 8, 13, 15, and 16, which warrant further studies. [ABSTRACT FROM AUTHOR]

Histone deacetylases (HDACs) play an essential role in the transcriptional regulation of cells through the deacetylation of nuclear histone and non-histone proteins and are promising therapeutic targets for the treatment of various diseases. Here, the synthesis of new compounds in which a hydroxamic acid residue is attached to differently substituted pyrimidine rings via a methylene group bridge of varying length as potential HDAC inhibitors is described. The target compounds were obtained by alkylation of 2-(alkylthio)pyrimidin-4(3H)-ones with ethyl 2-bromoethanoate, ethyl 4-bromobutanoate, or methyl 6-bromohexanoate followed by aminolysis of the obtained esters with hydroxylamine. Oxidation of the 2-methylthio group to the methylsulfonyl group and following treatment with amines resulted in the formation of the corresponding 2-amino-substituted derivatives, the ester group of which reacted with hydroxylamine to give the corresponding hydroxamic acids. The synthesized hydroxamic acids were tested as inhibitors of the HDAC4 and HDAC8 isoforms. Among the synthesized pyrimidine-based hydroxamic acids N-hydroxy-6-[6-methyl-2-(methylthio)-5-propylpyrimidin-4-yloxy]hexanamide was found to be the most potent inhibitor of both the HDAC4 and HDAC8 isoforms, with an IC50 of 16.6 µM and 1.2 µM, respectively.

Attempts to furnish antitumor structural templates that can prevent the occurrence of drug-induced hyperuricemia spurred us to generate xanthine oxidase inhibitor-based hydroxamic acids and anilides. Specifically, the design strategy involved the insertion of febuxostat (xanthine oxidase inhibitor) as a surface recognition part of the HDAC inhibitor pharmacophore model. Investigation outcomes revealed that hydroxamic acid 4 elicited remarkable antileukemic effects mediated via HDAC isoform inhibition. Delightfully, the adduct retained xanthine oxidase inhibitory activity, though xanthine oxidase inhibition was not the underlying mechanism of its cell growth inhibitory effects. Also, compound 4 demonstrated significant in-vivo anti-hyperuricemic (PO-induced hyperuricemia model) and antitumor activity in an HL-60 xenograft mice model. Compound 4 was conjugated with poly (ethylene glycol) poly(aspartic acid) block copolymer to furnish pH-responsive nanoparticles (NPs) in pursuit of circumventing its cytotoxicity towards the normal cell lines. SEM analysis revealed that NPs had uniform size distributions, while TEM analysis ascertained the spherical shape of NPs, indicating their ability to undergo self-assembly. HDAC inhibitor 4 was liberated from the matrix due to the polymeric nanoformulation's pH-responsiveness, and the NPs demonstrated selective cancer cell targeting ability. [Display omitted] • Febuxostat (xanthine oxidase inhibitor) was installed in the HDAC inhibitor pharmacophore. • Hydroxamic acid 4 elicited remarkable antileukemic effects via HDAC inhibition. • PH-responsive nanoparticles (NPs) of compound 4 were prepared. • SEM analysis revealed that NPs had uniform size distributions. • Polymer nanoformlation of HDAC inhibitor 4 manifested pH sensitive behaviour. [ABSTRACT FROM AUTHOR]

In our previous work, the clinical phase II HDAC inhibitor quisinostat was identified as a promising antimalarial agent through a drug repurposing strategy, but its safety was a matter of concern. Herein, further medicinal chemistry methods were used to identify new chemical entities with greater effectiveness and safety than quisinostat. In total, 38 novel hydroxamic acid derivatives were designed and synthesized, and their in vitro antimalarial activities were systematically investigated. These compounds at nanomolar concentrations showed inhibitory effects on wild-type and drug-resistant Plasmodium falciparum strains in the erythrocyte stage. Among them, compound 30, after oral administration, resulted in complete elimination of parasites in mice infected with Plasmodium yoelii, and also exhibited better safety and metabolic properties than observed in our previous work. Mechanistically, compound 30 upregulated plasmodium histone acetylation, according to western blotting, thus suggesting that it exerts antimalarial effects through inhibition of Plasmodium falciparum HDAC enzymes.

Isoform-selective histone deacetylase (HDAC) inhibition is promoted as a rational strategy to develop safer anti-cancer drugs compared to non-selective HDAC inhibitors. Despite this presumed benefit, considerably more non-selective HDAC inhibitors have undergone clinical trials. In this report, we detail the design and discovery of potent HDAC inhibitors, with 1-benzhydryl piperazine as a surface recognition group, that differ in hydrocarbon linker. In vitro HDAC screening identified two selective HDAC6 inhibitors with nanomolar IC50 values, as well as two non-selective nanomolar HDAC inhibitors. Structure-based molecular modeling was employed to study the influence of linker chemistry of synthesized inhibitors on HDAC6 potency. The breast cancer cell lines (MDA-MB-231 and MCF-7) were used to evaluate compound-mediated in vitro anti-cancer, anti-migratory, and anti-invasive activities. Experiments on the zebrafish MDA-MB-231 xenograft model revealed that a novel non-selective HDAC inhibitor with a seven-carbon-atom linker exhibits potent anti-tumor, anti-metastatic, and anti-angiogenic effects when tested at low micromolar concentrations. [ABSTRACT FROM AUTHOR]