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A π-type hydrogen bonding between the OH group and the π electron is a crucial factor for the conformational preference of the molecular structure with a flexible group. However, the information on the effect of the substituent on the OH/π interaction is insufficient. The laser-induced fluorescence (LIF) excitation, the dispersed fluorescence (DF), the IR–UV hole-burning, and the IR dip spectra of jet-cooled 2-(4-methoxyphenyl)ethanol were measured for the first time. Almost all bands observed in the spectral region of 35 550–36 500 cm−1 in the LIF excitation spectrum were successfully assigned with the DF and the IR–UV hole-burning spectra coupled with the quantum chemical calculation at M06-2x/6-311G and MP2/6-311G levels. Five conformers were found in the LIF excitation spectrum. The most stable conformer was Ggπ, and the second most stable conformer was Ggπ′ (the trans rotamer of the methoxy group for Ggπ). Ggπ and Ggπ′ had the OH group directed toward the π electron system of the benzene ring. The OH stretching frequency of Ggπ/Ggπ′ of MPE in the IR dip spectra was red-shifted against that of Ggπ of phenylethanol, indicating that the introduction of the methoxy group would enhance the intramolecular OH/π interaction. In addition, the torsional vibration between the benzene ring and the side chain (−CH2CH2OH) (mode 63) was observed in the DF spectra of the Ggπ–00 and Ggπ′–00 band excitation, but their intensities were rather different, resulting from the different orientation of the OH group for each conformer toward the π electron system. The methoxy group would increase the negative charge on the benzene ring and would enhance the intramolecular OH/π interaction through the electrostatic interaction. [ABSTRACT FROM AUTHOR]

Homogeneous earth abundant transition-metal electrocatalysts capable of carbon dioxide (CO2) reduction to generate value-added chemical products are a possible strategy to minimize rising anthropogenic CO2 emissions. Previously, it was determined that Cr-centered bipyridine-based N2O2 complexes for CO2 reduction are kinetically limited by a proton-transfer step during C–OH bond cleavage. Therefore, it was hypothesized that the inclusion of pendent relay groups in the secondary coordination sphere of these molecular catalysts could increase their catalytic activity. Here, it is shown that the introduction of a pendent methoxy group favorably impacts a pre-equilibrium protonation prior to the catalytic resting state, resulting in a significant increase in catalytic activity without a loss of product selectivity for generating carbon monoxide (CO) from CO2. Interestingly, combining the pendent methoxy group with a cationic acid causes a positive shift of the catalytic reduction potential of the system, while maintaining increased activity and quantitative selectivity. This work suggests that tuning the secondary coordination sphere with respect to cationic proton sources can result in activity improvements by modifying the kinetic and thermodynamic aspects of proton transfer in the catalytic cycle. [ABSTRACT FROM AUTHOR]

The network structure and reactivity of suitable restoration agent consisting of silane coupling agents (SCAs) of the brittle walls of a cultural heritage site located underground in a desert area in Egypt were investigated using 1H pulsed nuclear magnetic resonance (pulse NMR). It should possess both high coagulation strength and ductility to ensure that it can withstand an earthquake; it should also contain ethoxy rather than methoxy groups, which generate toxic methanol. The solidification rate for the SCA or oligomer with ethoxy groups was lower than those with methoxy groups; however, the final polycondensates showed the same relaxation time (hardness). The difference spectrum was developed newly to analyze the network structure combined higher strength and ductility. The distribution of crosslinking degree of such polycondensates was narrow, and the amount of lower crosslinking degree was small. On the other hand, the distribution was wide in the polycondensates with ductility but lower strength. From the compression tests of model sand solidified with the restoration agent for both methoxy and ethoxy types showed the superior properties combined higher strength and ductility. The pulse NMR experiment was useful for estimating the solidification rate and the network structure. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have garnered growing interest in the field of biomedicine; however, their application in sonodynamic therapy remains underexplored due to limited understanding of their intrinsic activity and structure–property relationships. Here, we present a pore wall chemistry modulation strategy for empowering sonodynamic activity to two‐dimensional (2D) COF heterojunctions through in situ growth of COFs on bismuth oxycarbonate nanosheets (B NSs). Compared to the negligible sonodynamic effects observed in the pristine B NSs, the 2D heterojunction with vinyl‐decorated COF pore walls demonstrates a 3.6‐fold enhancement in sonocatalytic singlet oxygen generation. This performance also significantly outperforms that of isoreticular COFs functionalized with methoxy or non‐substituted groups. Mechanistic studies reveal that the vinyl groups in the B@COF (BC) heterojunction facilitate the separation and transfer of charge carriers while also enhancing the adsorption of oxygen molecules. Furthermore, peroxymonosulfate (PMS) loading into the porous COFs boosts the therapeutic efficacy of antitumor nanotherapy via sonocatalytic dual oxidative species generation. These findings underscore the critical role of pore wall chemistry in modulating the sonocatalytic properties of COFs, and advance the development of COF‐based sonosensitizers for pro‐oxidative applications. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) incorporating oligo(phenylenevinylene) units have shown promise in enhancing photocatalytic hydrogen evolution. This study presents a series of linear oligo(phenylenevinylene)-based COFs with various ratios of β-ketoenamine to imine linkages. The COFs-950-OMe are crystalline, exhibiting higher surface area compared to amorphous COFs-950, due to the introduction of methoxy side groups. [ABSTRACT FROM AUTHOR]

The aryl hydrocarbon receptor (AhR) is an environmentally sensitive transcription factor (TF) historically associated with carcinogenesis initiation via the activation of numerous carcinogens. Nowadays, the AhR has been attributed to multiple endogenous functions to maintain cellular homeostasis. Moreover, crosstalk, often reciprocal, has been found between the AhR and several other TFs, particularly estrogen receptors (ERs) and nuclear factor erythroid 2-related factor-2 (Nrf2). Adequate modulation of these signaling pathways seems to be an attractive strategy for cancer chemoprevention. Several naturally occurring and synthetically modified AhR or ER ligands and Nrf2 modulators have been described. Sulfur-containing derivatives of glucosinolates, such as indole-3-carbinol (I3C), and stilbene derivatives are particularly interesting in this context. I3C and its condensation product, 3,3′-diindolylmethane (DIM), are classic examples of blocking agents that increase drug-metabolizing enzyme activity through activation of the AhR. Still, they also affect multiple essential signaling pathways in preventing hormone-dependent cancer. Resveratrol is a competitive antagonist of several classic AhR ligands. Its analogs, with ortho-methoxy substituents, exert stronger antiproliferative and proapoptotic activity. In addition, they modulate AhR activity and estrogen metabolism. Their activity seems related to a number of methoxy groups introduced into the stilbene structure. This review summarizes the data on the chemopreventive potential of these classes of phytochemicals, in the context of AhR and its crosstalk modulation. [ABSTRACT FROM AUTHOR]

The synthesis of group IV metallocene precatalysts for the polymerization of propylene generally yields two different isomers: The racemic isomer that produces isotactic polypropylene (iPP) and the meso isomer that produces atactic polypropylene (aPP). Due to its poor physical properties, aPP has very limited applications. To avoid obtaining blends of both polymers and thus diminish the mechanical and thermal properties of iPP, the meso metallocene complexes need to be separated from the racemic ones tediously—rendering the metallocene‐based polymerization of propylene industrially far less attractive than the Ziegler/Natta process. To overcome this issue, we established an isomerization protocol to convert meso metallocene complexes into their racemic counterparts. This protocol increased the yield of iPP by 400 % while maintaining the polymer's excellent physical properties and was applicable to both hafnocene and zirconocene complexes, as well as different precatalyst activation methods. Through targeted variation of the ligand frameworks, methoxy groups at the indenyl moieties were found to be the structural motifs responsible for an isomerization to take place—this experimental evidence was confirmed by density functional theory calculations. Liquid injection field desorption ionization mass spectrometry, as well as 1H and 29Si nuclear magnetic resonance studies, allowed the proposal of an isomerization mechanism. [ABSTRACT FROM AUTHOR]

The search for alternative non‐noble transition metal catalysts able to evolve hydrogen has been the focus of intense research. Molecular complexes bearing redox‐active ligands have been reported as efficient electrocatalysts for hydrogen evolution reaction (HER). This study showcases a new family of nickel‐thiosemicarbazone complexes displaying significant activity for HER in DMF solvent using trifluoracetic acid as proton source. Following previous works in our group, the ligand was stereochemically tailored, placing methoxy groups at different locations and considering various combinations of positions. Three complexes within the series were shown to outperform the parent catalyst bearing the methoxy group in para position. Overall, the nickel catalyst having the chemical substituent in meta position displays the best catalytic performances while having the lowest overpotential. These results support that ligand stereochemical tailoring in metal complexes improves electrocatalytic HER and suggest that ligand tuning is a promising direction to enhance catalyst performances. [ABSTRACT FROM AUTHOR]

The title compound, 4-(10-phenyl-9-anthracenyl)-1,2-benzenediol, was synthesized using a two-step protocol. In the first step, 9-phenyl,10-bromoanthracene was coupled to 3,4-dimethoyphenylboronic acid by employing Pd(PPh3)4 as the catalyst and potassium carbonate as the base. Methoxy group removal was effected using HBr in the presence of acetic acid in the second step. Overall, two novel 9,10-diphenylanthracence-based compounds were synthesized in this work; standard spectroscopic techniques and high-resolution mass spectrometry were employed in their characterization. The photophysical properties of these compounds are also reported. These compounds are potentially useful as sensors, catalysts and building blocks for larger architectures. [ABSTRACT FROM AUTHOR]

Among polymer wastes, poly(ethylene terephthalate) (PET) is the most important commercial thermoplastic polyester. Less than 30% of total PET production is recycled into new products. Therefore, large amounts of waste PET need to be recycled. We describe a feasible approach for the direct application of the glycolysis products of PET (GP-PET), without further purification, for the synthesis of value-added products. It was established that GP-PET is valorized via phosphorylation with phenylphosphonic dichloride (PPD), as well as with trimethyl phosphate (TMP). When PPD is used, a condensation reaction takes place with the evolution of hydrogen chloride. During the interaction between GP-PET and TMP, the following reactions take place simultaneously: a transesterification with the participation of the hydroxyl group of GP-PET and the methoxy group of TMP and an exchange reaction between the ester group of GP-PET and the methyl ester group of TMP. The occurrence of the exchange reaction was confirmed by 1H, 31P, 13C NMR, and GPC analysis. Thermogravimetric analysis (TGA) revealed that the percentage of a carbon residual (CR) implies the possibility of using the end products as flame retardant (FR) additives, especially for polyurethanes as well as thermal stabilizers of polymer materials or Li-ion cells. [ABSTRACT FROM AUTHOR]

This article discusses the design, synthesis, and evaluation of amide derivatives of 1,3,4-thiadiazolyl pyridinyl isoxazoles for their anticancer properties. The compounds were tested against four human cancer cell lines and showed moderate to good activity, with three compounds (13a, 13b, and 13c) exhibiting the most potent activity. Molecular docking studies were also conducted, which suggested the effectiveness of the binding mode of the Tubulin B chain receptor and these three compounds. The article provides detailed information on the synthesis process, characterization of the compounds, and their cytotoxicity results. Another document provides information on the synthesis and characterization of several compounds (13b, 13c, 13d, 13e, and 13f) with specific chemical structures. The compounds were prepared using a specific method and their physical properties, such as melting point and spectral data, were determined. The document also includes the calculated and found values for the elemental composition of each compound. A separate document provides information on the synthesis and characterization of several compounds (13g, 13h, 13i, and 13j) and their molecular docking studies. The compounds were prepared using a specific method and purified through column chromatography. The physical properties and spectroscopic data of the compounds are provided. The compounds were then subjected to molecular docking studies using PyRx software. The MTT assay was also performed to evaluate the cytotoxicity of the [Extracted from the article]

This article discusses the design, synthesis, and evaluation of amide derivatives of thienopyrimidine isoxazoles for their anticancer properties. The researchers synthesized a library of compounds and tested their anticancer activities against four different cancer cell lines. Two compounds, 13a and 13e, showed particularly promising results. Molecular docking analysis revealed the key interactions of the compounds with the target protein, ATR kinase. The document also describes the synthesis, characterization, and cytotoxic activity testing of several other compounds, as well as the methods used for molecular docking studies. The study was financially supported by the Deanship of Scientific Research, King Khalid University, and no conflicts of interest were reported by the authors. [Extracted from the article]

Cellulose is insoluble in water and most of the ionic liquids, but due to the substitution of hydroxyethyl, hydroxypropyl, and methoxy groups with the glucose residue, the cellulose derivatives Hydroxyethyl Cellulose (HEC) and Hydroxypropyl Methyl Cellulose (HPMC) become soluble in cold as well as hot water. The aim of the present investigations is to probe the origin of the enhanced solubility in cellulose derivatives HEC, and HPMC at atomic scale resolution by applying 13C cross-polarization magic angle spinning (CP-MAS) SSNMR experiment, 13C two-dimensional phase-adjusted spinning sideband (2DPASS) CP-MAS SSNMR experiment, and site specific 13C spin–lattice relaxation time measurements. The local-correlation time is also calculated for HEC and HPMC by using values of spin–lattice relaxation time and principal components of CSA parameters. The 13C spin–lattice relaxation time and 13C local correlation time are drastically decreased in HEC, and HPMC compared to cellulose, suggesting a notable increase in the motional dynamics of cellulose derivatives. Hence, the motional dynamics is enhanced in cellulose derivatives due to esterification, and is one of the reasons of enhanced solubility. The microscopic parameter, the nuclear spin–lattice relaxation rate of polysaccharide is interrelated with the solubility, a macroscopic property. [ABSTRACT FROM AUTHOR]

Fluorinated ether‐based electrolytes are commonly employed in lithium metal batteries (LMBs) to attenuate the coordination ability of ether solvents with Li+ and induce inorganic‐rich interphase, whereas fluorination inevitably introduces exorbitant production expenses and environmental anxieties. Herein, a non‐fluorinated molecular design strategy has been conceptualized by incorporating methoxy as an electron‐donating group to generate a quasi‐conjugate effect for tuning the affinity of Li+‐solvent, thereby enabling the cyclic ether solvent 2‐methoxy‐1,3‐dioxolane with weak solvation ability and exceptional Li metal‐compatibility. Accordingly, the optimized electrolyte exhibits anion‐dominant solvation structure for inorganic‐rich interphase and fulfills an impressive Li plating/stripping Coulombic efficiency of 99.6 %. As‐fabricated Li||LiFePO4 full cells with limited Li (N/P=2.5) showcase a high capacity retention of 83 % after 150 cycles, indicating excellent cycling stability. Moreover, the full LMBs demonstrate exceptional tolerance towards a wide temperature range from −20 °C to 60 °C, displaying a remarkable capacity retention of 90 % after 110 cycles at −20 °C. Such a molecular design strategy offers a promising avenue for electrolyte engineering beyond fluorination in order to cultivate high‐performance LMBs. [ABSTRACT FROM AUTHOR]

AbstractIn the present work, five pyrazole-hydrazone biomolecule ligands (L1–L5) were synthesized by condensation between 1H-pyrazole-3-carbohydrazide (2) and aromatic benzaldehydes. Their corresponding structures were elucidated employing NMR and FT-IR spectra and ESI-MS data. Li-Cu(II) complexes (i = 1–5) were evaluated for catecholase activity in situ at standard conditions. The findings disclose that the catecholase oxidation rate varies with the substituted functional groups in ligand and the anion type in the copper (II) salt. Catecholase activity results showed that the L(i = 1–5) -Cu(II)SO4 complexes exhibited efficient catalytic activity, and a maximum activity of 105 ± 42 µM.min−1 is obtained with L5-Cu(II)SO4. DFT and NBO calculations have been carried out to identify the global reactivity and the strength of interaction bonds between the donors and acceptors in L1–L5. The optimized structure of L1–L3 and L5 were found planar, while that of L4 is out of the molecular plan and forms a torsion angle of 18 degrees due to the presence of methoxy and hydroxyl group at meta and para. In L4, the 5-methyl-1H-pyrazole moiety. NBO findings show that the strongest interactions in L1–L5 are those involved in the electronic transition from π-bonding → π*-antibonding and LP → π*- antibonding molecular orbitals. Further, the anti-SARS-CoV-2 of L1–L5 are investigated by estimating their binding affinities into its binding. The docking results reveal that L1–L5 may act as SARS-CoV-2 main protease inhibitors with estimated binding energies in the −6.00 to −8.0 kcal.mol−1 range. [ABSTRACT FROM AUTHOR]

Agrobacterium tumefaciens can harm various fruit trees, leading to significant economic losses in agricultural production. It is urgent to develop new pesticides to effectively treat this bacterial disease. In this study, four new sesquiterpene derivatives, trichoderenes A-D (1-4), along with six known compounds (5-10), were obtained from the marine-derived fungus Trichoderma effusum. The structures of 1-4 were elucidated by extensive spectroscopic analyses, and the calculated ECD, ORD, and NMR methods. Structurally, the hydrogen bond formed between the 1-OH group and the methoxy group enabled 1 to adopt a structure resembling that of resorcylic acid lactones, thereby producing the ECD cotton effect. Compound 3 represents the first example of C12 norsesquiterpene skeleton. Compounds 1-10 were tested for their antimicrobial activity against A. tumefactions. Among them, compounds 1-3 and 8-10 exhibited inhibitory activity against A. tumefactions with MIC values of 3.1, 12.5, 12.5, 6.2, 25.0, and 12.5 µg/mL, respectively. [ABSTRACT FROM AUTHOR]

Blood–brain barrier (BBB) disruption is a major pathophysiological event of ischemic stroke. Brain microvascular endothelial cells are critical to maintain homeostasis between central nervous system and periphery. Resveratrol protects against ischemic stroke. 3,3′,4,5′‐tetramethoxy‐trans‐stilbene (3,3′,4,5′‐TMS) and 3,4′,5‐trimethoxy‐trans‐stilbene (3,4′,5‐TMS) are resveratrol derivatives with addition of methoxy groups, showing better pharmacokinetic performance. We aimed to explore their protective effects and underlying mechanisms. Oxygen–glucose deprivation (OGD) model was applied in bEnd.3 cell line, mouse brain microvascular endothelium to mimic ischemia. The cells were pre‐treated with 3,3′,4,5′‐TMS or 3,4′,5‐TMS (1 and 5 μM, 24 h) and then subjected to 2‐h OGD injury. Cell viability, levels of proinflammatory cytokines and reactive oxygen species (ROS), and protein expressions were measured by molecular assays and fluorescence staining. OGD injury triggered cell death, inflammatory responses, ROS production and nuclear factor‐kappa B (NF‐κB) signalling pathway. These impairments were remarkably attenuated by the two stilbenes, 3,3′,4,5′‐TMS and 3,4′,5‐TMS. They also alleviated endothelial barrier injuries through upregulating the expression of tight junction proteins. Moreover, 3,3′,4,5′‐TMS and 3,4′,5‐TMS activated 5′ adenosine monophosphate‐activated protein kinase (AMPK) and endothelial nitric oxide synthase (eNOS). Overall, 3,3′,4,5′‐TMS and 3,4′,5‐TMS exert protective effects against OGD damage through suppressing cell death, inflammatory responses, oxidative stress, as well as BBB disruption on bEnd.3 cells. [ABSTRACT FROM AUTHOR]

This study reports the reversible solubility switching of a polymer triggered by non‐phototoxic visible light. A photochromic polymerizable azobenzene monomer with four methoxy groups at the ortho‐position (mAzoA) was synthesized, exhibiting reversible photoisomerization between trans‐ and cis‐states using green (546 nm) and blue light (436 nm). Free radical copolymerization of hydrophilic dimethylacrylamide (DMAAm) with mAzoA produced a light‐responsive random copolymer (P(mAzoA‐r‐DMAAm)) that shows a reversible photochromic reaction to visible light. Optimizing mAzoA content resulted in P(mAzoA10.7‐r‐DMAAm)3.0 kDa exhibiting LCST‐type phase separation in PBS (pH 7.4) with trans‐ and cis‐states at 39.2 °C and 32.9 °C, respectively. The bistable temperature range of 6.3 °C covers 37 °C, suitable for mammalian cell culture. Reversible solubility changes were demonstrated under alternating green and blue light at 37 °C. 1H NMR indicated significant retardation of thermal relaxation from cis‐ to trans‐states, preventing undesired thermal mechanical degradation. Madin Darby Canine Kidney (MDCK) cells adhered to the P(mAzoA‐r‐DMAAm) hydrogel, confirming its non‐cytotoxicity and potential for biocompatible interfaces. This principle is useful for developing hydrogels that can reversibly stimulate cells mechanically or chemically in response to visible light. [ABSTRACT FROM AUTHOR]

The chemical and biological conversion of biomass-derived lignin is a promising pathway for producing valuable low molecular weight aromatic chemicals, such as vanillin or guaiacol, known as lignin monomers (LMs). Various methods employing chromatography and electrospray ionization-mass spectrometry (ESI–MS) have been developed for LM analysis, but the impact of LM chemical properties on analytical performance remains unclear. This study systematically optimized ESI efficiency for 24 selected LMs, categorized by functionality. Fractional factorial designs were employed for each LM to assess ESI parameter effects on ionization efficiency using ultra-high-performance supercritical fluid chromatography/ESI–MS (UHPSFC/ESI–MS). Molecular descriptors were also investigated to explain variations in ESI parameter responses and chromatographic retention among the LMs. Structural differences among LMs led to complex optimal ESI settings. Notably, LMs with two methoxy groups benefited from higher gas and sheath gas temperatures, likely due to their lower log P and higher desolvation energy requirements. Similarly, vinyl acids and ketones showed advantages at elevated gas temperatures. The retention in UHPSFC using a diol stationary phase was correlated with the number of hydrogen bond donors. In summary, this study elucidates structural features influencing chromatographic retention and ESI efficiency in LMs. The findings can aid in developing analytical methods for specific technical lignins. However, the absence of an adequate number of LM standards limits the prediction of LM structures solely based on ESI performance data. [ABSTRACT FROM AUTHOR]

This study focuses on the synthesis and structural characterization of new compounds that integrate thiazolidine-2,4-dione, acridine moiety, and an acetamide linker, aiming to leverage the synergistic effects of these pharmacophores for enhanced therapeutic potential. The newly designed molecules were efficiently synthesized through a multi-step process and subsequently transformed into their hydrochloride salts. Comprehensive spectroscopic techniques, including nuclear magnetic resonance (NMR), high-resolution mass spectrometry (HRMS), infrared (IR) spectroscopy, and elemental analysis, were employed to determine the molecular structures of the synthesized compounds. Biological evaluations were conducted to assess the therapeutic potential of the new compounds. The influence of these derivatives on the metabolic activity of various cancer cell lines was assessed, with IC50 values determined via MTT assays. An in-depth analysis of the structure–activity relationship (SAR) revealed intriguing insights into their cytotoxic profiles. Compounds with electron-withdrawing groups generally exhibited lower IC50 values, indicating higher potency. The presence of the methoxy group at the linking phenyl ring modulated both the potency and selectivity of the compounds. The variation in the acridine core at the nitrogen atom of the thiazolidine-2,4-dione core significantly affects the activity against cancer cell lines, with the acridin-9-yl substituent enhancing the compounds' antiproliferative activity. Furthermore, compounds in their hydrochloride salt forms demonstrated better activity against cancer cell lines compared to their free base forms. Compounds 12c·2HCl (IC50 = 5.4 ± 2.4 μM), 13d (IC50 = 4.9 ± 2.9 μM), and 12f·2HCl (IC50 = 4.98 ± 2.9 μM) demonstrated excellent activity against the HCT116 cancer cell line, and compound 7d·2HCl (IC50 = 4.55 ± 0.35 μM) demonstrated excellent activity against the HeLa cancer cell line. Notably, only a few tested compounds, including 7e·2HCl (IC50 = 11.00 ± 2.2 μM), 7f (IC50 = 11.54 ± 2.06 μM), and 7f·2HCl (IC50 = 9.82 ± 1.92 μM), showed activity against pancreatic PATU cells. This type of cancer has a very high mortality due to asymptomatic early stages, the occurrence of metastases, and frequent resistance to chemotherapy. Four derivatives, namely, 7e·2HCl, 12d·2HCl, 13c·HCl, and 13d, were tested for their interaction properties with BSA using fluorescence spectroscopic studies. The values for the quenching constant (Ksv) ranged from 9.59 × 104 to 10.74 × 104 M−1, indicating a good affinity to the BSA protein. [ABSTRACT FROM AUTHOR]

Biological conversion of lignin from biomass offers a promising strategy for sustainable production of fuels and chemicals. However, aromatic compounds derived from lignin commonly contain methoxy groups, and O -demethylation of these substrates is often a rate-limiting reaction that influences catabolic efficiency. Several enzyme families catalyze aromatic O -demethylation, but they are rarely compared in vivo to determine an optimal biocatalytic strategy. Here, two pathways for aromatic O -demethylation were compared in Pseudomonas putida KT2440. The native Rieske non-heme iron monooxygenase (VanAB) and, separately, a heterologous tetrahydrofolate-dependent demethylase (LigM) were constitutively expressed in P. putida , and the strains were optimized via adaptive laboratory evolution (ALE) with vanillate as a model substrate. All evolved strains displayed improved growth phenotypes, with the evolved strains harboring the native VanAB pathway exhibiting growth rates ∼1.8x faster than those harboring the heterologous LigM pathway. Enzyme kinetics and transcriptomics studies investigated the contribution of selected mutations toward enhanced utilization of vanillate. The VanAB-overexpressing strains contained the most impactful mutations, including those in VanB, the reductase for vanillate O- demethylase, PP_3494, a global regulator of vanillate catabolism, and fghA , involved in formaldehyde detoxification. These three mutations were combined into a single strain, which exhibited approximately 5x faster vanillate consumption than the wild-type strain in the first 8 h of cultivation. Overall, this study illuminates the details of vanillate catabolism in the context of two distinct enzymatic mechanisms , yielding a platform strain for efficient O -demethylation of lignin-related aromatic compounds to value-added products. • Depolymerization of lignin, followed by bioconversion, is a promising strategy to convert lignin to valuable products. • Methoxylated monomers, like vanillate, must undergo O -demethylation to enter catabolic pathways in aerobic bacteria. • Vanillate O-demethylation pathways were compared in Pseudomonas putida KT2440, focusing on the LigM and VanAB systems. • ALE optimized each pathway, but the optimized VanAB pathway demonstrated faster vanillate utilization. • Mutations were reverse-engineered into P. putida to generate an improved vanillate biocatalyst for valorization of lignin. [ABSTRACT FROM AUTHOR]

For the first time, the oxidative polymerizations of o/m-anisidines and o-toluidine were carried out by ammonium peroxydisulfate in organic medium. According to the results of UV–Vis, 1H NMR and IR spectral methods the structures of the synthesized poly(o-anisidine) coincide with emeraldine base. Formation of dihydrobenzoxazole units was shown for poly(m-anisidine), which lowers the amount of both quinonediimine and methoxy groups in polymer. Obtained polymers show enhanced solubility in organic solvents. Thermal analysis shows that at 800 °C polyanisidines lost only 48% of their initial weight. Room temperature conductivity measurements show correspondingly 2.5 × 10−1 S/cm and 9 × 10−3 S/cm values for poly(o-anisidine) and poly(o-toluidine) when doped with inorganic acids. The ionization potential and electron affinities of obtained polymers were estimated by cyclic voltammograms. [ABSTRACT FROM AUTHOR]

This article discusses the use of iodine(III)-mediated ring-contraction reactions in both halogenated and non-halogenated solvents. The study compares the yields of ring-contraction reactions using different solvents and investigates the behavior of different derivatives of 1,2-dihydronaphthalene. The results show that using halogenated solvents leads to higher yields. The article also provides a detailed account of the synthesis and purification of various organic compounds, including their yields, physical properties, and spectroscopic data. Additionally, it provides information on the synthesis and characterization of three specific compounds, along with supporting information for further reference. [Extracted from the article]

A series of novel 2‐(2‐pyridyl)quinazoline luminophores containing a donor aryl fragment at position 4 and methyl or methoxy groups at benzene ring has been synthesized by efficient three‐step route. The linear optical properties have been studied by UV/Vis absorption and photoluminescence spectra in two solvents. We revealed that introduction of additional methyl group or the replacement of methyl substituents with methoxy ones lead to sequentially shift of absorption and emission maximum to blue region. 9H‐Carbazol‐9‐yl‐containing derivative is characterized by hypsochromically shifted absorption band compared to its NEt2 and NPh2 counterparts. Unlike 9H‐carbazol‐9‐yl‐derivative, Et2N‐ and Ph2N‐bearing quinazolines demonstrate considerable decrease in quantum yield values when going from toluene to MeCN. Solvatochromic properties have been explored, the pronounced bathochromic shift was observed in fluorescence spectra with the increase of solvents polarity. Moreover, the compounds show significant shift of emission band with the increase of water fraction in DMSO/H2O mixture. Two‐photon optical properties have been also studied, the two‐photon absorption cross‐sections in MeCN and toluene reached 120 GM and 210 GM, respectively. The presence of additional methyl group has little impact on δTPA value, while introduction of methoxy substituents dramatically decreases TPA cross sections. Additionally, a quantum‐chemical calculations of synthesized compounds were performed to support the experimental data. [ABSTRACT FROM AUTHOR]

This article discusses the synthesis of substituted ß-homoprolines using rhodium catalysis. ß-Homoproline is a variant of ¿-proline and is found in natural products and pharmaceuticals. The article describes the development of a new method for synthesizing ß-homoprolines, which involves the cyclization of isoxazolidin-5-ones using a rhodium catalyst. The authors demonstrate the scope and limitations of this method and discuss the downstream transformations that can be performed on the resulting ß-homoprolines. Overall, this research provides valuable insights into the synthesis and potential applications of ß-homoprolines. [Extracted from the article]

Two new triarylamine-based diamine monomers, namely, N,N′-bis(4-methoxyphenyl)-N,N′-bis(4-(4-aminophenyl-4′-methoxyphenylamino)phenyl)-p-phenylenediamine (3) and N,N′-bis(4-methoxyphenyl)-N,N′-bis(4-((4-aminophenyl-1-naphthyl)amino)phenyl)-p-phenylenediamine (7), were successfully synthesized and led to two series of electroactive polyamides by polycondensation reactions with common aromatic dicarboxylic acids. The polymers demonstrated multicolored electrochromism, high optical contrast, and remarkable enhancements in redox and electrochromic stability. Compared to other triarylamine-based polymers, the studied polyamides exhibited enhanced electrochromic stability (only 3~6% decay of its coloration efficiency at 445 nm after 14,000 switching cycles) at the first oxidation stage. The polyamides also showed strong absorption in the near-infrared region upon oxidation. Polymers with multicolored electrochromism and high redox stability can be developed by incorporation of four triarylamine cores in each repeat unit and electron-donating methoxy groups on the active sites of the triphenylamine units. [ABSTRACT FROM AUTHOR]

Biorefining of lignocellulosic biomass via a lignin first approach delivers a range of products with high oxygen content. Besides pulp, a lignin oil rich in guaiacols and syringols is obtained bearing multiple C(aryl)–OH and C(aryl)–OMe groups, typically named phenolics. Similarly, technical lignin can be used but is generally more difficult to process providing lower yields of monomers. Removal of the hydroxy and methoxy groups in these oxygenated arenes is challenging due to the inherently strong C–O bonds, in addition to the steric and electronic deactivation by adjacent –OH or –OMe groups. Moreover, chemoselective removal of a specific group in the presence of other similar functionalities is non-trivial. Other side-reactions such as ring saturation and transalkylation further complicate the desired reduction process. In this overview, three different selective reduction reactions are considered. Complete hydrodeoxygenation removes both hydroxy and methoxy groups resulting in benzene and alkylated derivatives (BTX type products) which is often complicated by overreduction of the arene ring. Hydrodemethoxylation selectively removes methoxy groups in the presence of hydroxy groups leading to phenol products, while hydrodehydroxylation only removes hydroxy groups without cleavage of methoxy groups giving anisole products. Instead of defunctionalization via reduction transformation of C(aryl)–OH, albeit via an initial derivatization into C(aryl)–OX, into other functionalities is possible and also discussed. In addition to methods applying guaiacols and syringols present in lignin oil as model substrates, special attention is given to methods using mixtures of these compounds obtained from wood/technical lignin. Finally, other important aspects of C–O bond activation with respect to green chemistry are discussed. [ABSTRACT FROM AUTHOR]

This article explores a new method for the dichlorination of alkenes using iron complexes as catalysts. The authors describe a photocatalytic process that utilizes iron chloride and light-induced ligand-to-metal-charge transfer to generate reactive chlorine radicals. The reaction is efficient and selective, producing 1,2-dichloride compounds that are valuable intermediates in organic synthesis. The article also investigates the mechanism of the reaction and examines the range of substrates that can be used in this iron-catalyzed photodichlorination process. [Extracted from the article]

The method for the preparation of 3,6-disubstituted 1,2,4-triazines based on condensation reaction between easily available α-imino esters and isonitrosoacetophenone hydrazones was reported. The significant differences in reaction conditions, ratio of products, and yields between the developed method and the earlier reported approach were demonstrated. The corresponding 2,5-disubstituted pyridines were synthesized from the prepared 1,2,4-triazines, and their photophysical properties were studied. Studies of the photo-physical properties revealed low and moderate luminescence quantum yields, and negligible solvatochromic behavior in case of 4-methoxyphenylpyridine derivative due to the role of donating methoxy group, however, with a low linearity of a Lippert–Mataga plot. Nevertheless, 2,5-disubstituted pyridines are of interest due to simple protocols of synthesis, moderate photophysical properties, and potential applicability in different scientific and industrial areas. [ABSTRACT FROM AUTHOR]

Recent progress has shown promising advancements in enhancing the Reverse intersystem crossing (RISC) process between high‐energy triplet states (Tn, n ≥ 1) and radiative singlet states (Sm) through the utilization of the classic D‐A‐D' strategy. In this study, 12 molecules employing phenyl carbazole and a peripheral phenanthroimidazole as the donors and fused cores as acceptors are theoretically designed. Additionally, electron‐withdrawing groups such as fluorine and cyano, as well as electron‐donating group like methoxy, are incorporated into anthracene, napthaoxadiazole, and napthothiadiazole derivatives, acting as fused core components. Theoretical analyses reveal that among the molecules examined, eight adhere to the three golden principle rules, demonstrating a large energy gap between S1‐T1, the minimal ΔES1‐T2, and large T2‐T1. Additionally, these molecules exhibit significant Spin‐orbit coupling (SOC) and maintain a strong Hybridized local and charge transfer (HLCT) character, facilitating the fast hRISC from T2 to S1. The auxiliary inclusion of heteroatoms, such as oxygen and sulfur, on the anthracene core, aligns with the prerequisite strategy, ultimately reinforcing the SOC. Furthermore, replacing the methoxy group on the Nz bridge significantly enhances the SOC, resulting in a substantial increase in the hRISC rate (10 +08 s−1). Overall, the findings substantially elevate the photophysical attributes of the designed molecules through the utilization of the hRISC channel. [ABSTRACT FROM AUTHOR]

The bromination of eugenol using molecular bromine (Br2 ) has been widely reported. However, the outcomes have been inconsistent, and as a result, the specific steps of the bromination process have not been definitively established. This research aims to synthesize various derivatives of bromo eugenol, incorporating bromine atoms either in the alkene group, the aromatic ring, or both. The synthetic approaches employed include (1) direct bromination of eugenol using 1.2, 2.4, and 3.6 equivalents (equiv) of Br2 in chloroform, (2) bromination of eugenyl benzoate with 2.4 equiv of Br2 in chloroform, and (3) debromination of the 1,2-dibromide functionality in selected bromination products using an excess of zinc in ethanol. The bromination steps of eugenol were then proposed based on the composition of the products obtained. Alkene bromination of eugenol predominated with 1.2 equiv of Br2, followed by aromatic bromination with excess Br2 (2.4 and 3.6 equiv). Aromatic substitution primarily occurred at position 6 (ortho to the hydroxyl group) and subsequently at position 5 (para to the methoxy group). Based on these results, we propose that the bromination of eugenol with Br2 proceeds initially through electrophilic addition to the alkene group, followed by electrophilic substitution on the aromatic ring. Protection of the phenol as a benzoyl ester shifted the regioselectivity of the first aromatic bromination from position 6 to 5. Furthermore, the 1,2-dibromide group has been successfully removed by zinc, resulting in derivatives containing bromine atoms only at the aromatic ring. This is by far the first comprehensive report on the bromination of eugenol with Br2 and the first one reporting the bromination of alkene as the main route of bromination with a nearly equimolar amount of Br2 . [ABSTRACT FROM AUTHOR]

Tree-ring stable isotopes (TRSI) have the unique ability to capture inter-annual to multi-millennial climate trends and extremes if the appropriate data and methods are combined. However, there is still an ongoing debate about age-related biases in TRSI measurements that potentially affect the fidelity of their chronologies and subsequent climate reconstructions. Here, we investigate carbon and oxygen TRSI measurements in cellulose (δ 13C cell and δ 18O cell) and carbon and hydrogen ratios in lignin methoxy groups (δ 13C meth and δ 2H meth) of more than 60 living and relict pine (Pinus heldreichii) trees from northern Greece that span the period 512–2020 CE continuously. We identified significant (p < 0.01) level offsets between living and relict δ 18O cell values (1.49 mUr) that preclude, among others, the combination of living and relict wood series for reliable age-trend assessment, and we found distinct differences between cellulose and methoxy TRSI chronologies including contrasting recent trends in carbon, oxygen, and hydrogen isotope ratios suggesting that varying environmental signals are retained in the TRSI proxies. Assessments are supported by comparisons with well-established ontogenetic trends in tree-ring width and latewood maximum density to identify significant (p < 0.01) age-trends in relict δ 18O cell values between 50 and 190 years of cambial age, and in relict δ 13C meth and δ 2H meth values in tree rings older than 100 years. Relict δ 13C cell values, on the other hand, show increasing values between 50 and 80 years of cambial age (p < 0.01), but no evidence for long-term trends beyond these early stages. The combined assessment of multiple TRSI from cellulose and lignin methoxy groups contributes to a better understanding of the underlying physiological processes and extends the range of extractable climate information from the utilized tree-ring proxies. Our findings demonstrate that raw δ 13C cell data from Mt. Smolikas can be used for climate calibration and reconstruction purposes without the need for standardization (expect for rings ≤80 years of cambial age), potentially providing new insights into long-term climate variability in the eastern Mediterranean region. δ 18O cell , δ 13C meth , and δ 2H meth values, however, require detrending due to long-term age-related trends. [ABSTRACT FROM AUTHOR]

We report, an intramolecular ipso‐halocyclization of N‐arylpropynamides using readily available hypervalent iodine reagent as mild oxidant and alkali halides like KCl, KBr, and KI as the halogen source. Using this method, a broad range of valuable halogenated spiro[4.5]trienones can be obtained in an excellent yield at room temperature. Notably, this protocol doesn't require para‐substituents such as methoxy or fluoro group on the N‐aryl ring. Also, this reaction takes place in the absence of any metal catalyst under aqueous conditions and exhibits a broad substrate scope with high functional group tolerance. A plausible reaction mechanism is proposed based on control experiments. [ABSTRACT FROM AUTHOR]

This article provides a comprehensive overview of the synthesis and modification of organic fluorophores, which are organic compounds that emit light when excited. It discusses various synthetic reactions used to create these fluorescent molecules, with a focus on transition-metal-catalyzed C–H activation reactions. The article categorizes recent C–H activation reactions and evaluates their advantages and limitations. This information is valuable for researchers and readers interested in the field of organic fluorophores. The document also includes biographical information about the authors, Dr. Tapasi Chand and Dr. Manmohan Kapur. [Extracted from the article]

Treatment of isatin with ammonia in methanol under reflux, followed by hydrazine substitution of the methoxy group afforded isamic hydrazide in up to 79 % yield. Subsequent condensation of isamic hydrazide with selected aromatic ketones and aldehydes gave access to novel 2‐oxo‐1,2‐dihydro‐1′H‐spiro[indoline‐3,2′‐quinazoline]‐4′‐carbohydrazones (4–11) in yields between 59 % and 74 %. Detailed structural analysis of synthesized compounds was done using spectroscopic techniques. Antibacterial screening of the hydrazone derivatives (4–11) demonstrated broad‐spectrum activity against evaluated bacterial strains, with inhibition zones ranging from 10 to 32 mm. Specifically, compound 9 exhibited superior activity compared to the standard streptomycin against various bacterial strains, including B. polymyxa (LIO), B. cereus (NCBI 6349), C. pyogenes (LIO), B. subtilis (NCBI 3610), S. aureus (NCBI 8588), E. coli (NCIB 86), P. aeruginosa (NCIB 950), and K. pneumoniae (NCIB 418). Moreover, the inhibitory concentrations of compound 9 were lower than those of streptomycin, underscoring its efficacy as a potential antibacterial agent. These findings suggest that the synthesized hydrazone derivatives possess significant potential as novel and effective antibacterial agents, warranting further exploration in the field of antibacterial drug development. [ABSTRACT FROM AUTHOR]

This article discusses a new method for synthesizing chromone C-glycosides using a Pd-catalyzed reaction. The researchers successfully applied this method to different glycals with various protecting groups, resulting in the production of glycosides with moderate to high yields. They also explored the potential of this approach for modifying natural products and pharmaceutical compounds linked to glycals, leading to the synthesis of their respective glycosides. The researchers further demonstrated the scalability of their method and its applicability in producing valuable products, including 2-deoxy-chromone C-glycosides. Overall, this research introduces a unique collection of chromone glycosides that could be beneficial for drug discovery efforts. [Extracted from the article]

This work presents the design, synthesis and biological activity of novel N-substituted benzimidazole carboxamides bearing either a variable number of methoxy and/or hydroxy groups. The targeted carboxamides were designed to investigate the influence of the number of methoxy and/or hydroxy groups, the type of substituent placed on the N atom of the benzimidazole core and the type of substituent placed on the benzimidazole core on biological activity. The most promising derivatives with pronounced antiproliferative activity proved to be N-methyl-substituted derivatives with hydroxyl and methoxy groups at the phenyl ring and cyano groups on the benzimidazole nuclei with selective activity against the MCF-7 cell line (IC50 = 3.1 μM). In addition, the cyano-substituted derivatives 10 and 11 showed strong antiproliferative activity against the tested cells (IC50 = 1.2–5.3 μM). Several tested compounds showed significantly improved antioxidative activity in all three methods compared to standard BHT. In addition, the antioxidative activity of 9, 10, 32 and 36 in the cells generally confirmed their antioxidant ability demonstrated in vitro. However, their antiproliferative activity was not related to their ability to inhibit oxidative stress nor to their ability to induce it. Compound 8 with two hydroxy and one methoxy group on the phenyl ring showed the strongest antibacterial activity against the Gram-positive strain E. faecalis (MIC = 8 μM). [ABSTRACT FROM AUTHOR]

The reaction mechanism of the Dakin reaction for three lignin model compounds was thoroughly investigated using density functional theory (DFT). A more comprehensive atomic and molecular level oxidation mechanism for the Dakin reaction was proposed, complementing the previously reported reaction process. The potential energy surface information for twelve possible channels was obtained at B3LYP/6–311 + G(d,p) level based on the geometry optimization together with the frequency calculation of the stationary points. The influence of substituent effects on the reaction energy barrier of Dakin reaction in lignin model compounds was estimated. The calculated results revealed that the rearrangement reaction of quinone structure primarily involves ring-forming and ring-opening of epoxy group, the ring-forming on O and C of benzene ring and ring-opening on C and C of benzene ring. The energy barriers of Dakin reaction decrease with an increase in the number of methoxy groups in lignin model compounds. Further elucidation of the Dakin reaction mechanism will provide a theoretical foundation for the development of more effective catalytic systems to enhance the valuable utilization of lignin in future applications. [ABSTRACT FROM AUTHOR]

This article discusses a new method for synthesizing 5-dialkylamino-1,2,4-oxadiazoles, which are important in drug discovery. The method involves using tertiary amines as temporary masked secondary amines, allowing for the direct construction of these compounds in a one-pot manner. The research provides a more efficient and facile approach for synthesizing these compounds, which have potential therapeutic applications. The article also provides detailed information on the synthesis and characterization of various N,N-dialkylamino-substituted 1,2,4-oxadiazoles, as well as piperazine-linked 1,2,4-oxadiazoles. The research was conducted at Chiang Mai University in Thailand and is supported by the university. [Extracted from the article]

This article provides an overview of heteroatom-embedded polycyclic aromatic compounds (hetero-PACs) and their importance in various scientific and technological fields. Hetero-PACs are structurally diverse compounds that contain multiple fused aromatic rings and embedded heteroatoms such as boron, nitrogen, oxygen, phosphorus, and sulfur atoms. They exhibit diverse optoelectronic properties and have applications in organic electronics and chemical biology. The article discusses the stepwise synthesis of hetero-PACs and the challenges associated with it. It then introduces the concept of heteroatom-embedding annulative π-extension (hetero-APEX) reactions as a more efficient synthetic strategy for hetero-PACs. Hetero-APEX reactions allow for the direct construction of fused heteroaromatic structures, offering advantages in terms of step-economy and late-stage tunability. The article concludes by highlighting the potential of hetero-APEX reactions in expanding the structural diversity of hetero-PACs and promoting the discovery of novel heteroaromatics with unique structures, properties, and functions. [Extracted from the article]

The process of creating a series of 3-amino-1-aryl-8-methoxy-1H-benzo[f]chromene-2-carbonitriles (4a-q) involved reacting 6-methoxynaphthalen-2-ol (1), the appropriate aromatic aldehydes (2a-q), and malononitrile (3) in an absolute ethanol/piperidine solution under Ultrasonic irradiation. However, the attempt to create 3-amino-1-aryl-1H-benzo[f]chromene-2,8-dicarbonitrile (6a, d, e) was unsuccessful when 6-cyanonaphthalen-2-ol (5) was stirred at room temperature, reflux, Microwave irradiation, or Ultrasonic irradiation. In addition, the target molecules were screened against Staphylococcus aureus (MRSA), Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Escherichia coli and Klebsiella pneumonia, as well as a panel of three human cancer cells lines such as MCF-7, HCT-116, HepG-2 and two normal cell lines HFL-1 and WI-38. The obtained results confirmed that the pyran derivatives (4 m, i, k) which have a double chlorine at 3,4/2,3/2,5-positions, a single halogen atom 3-Cl/4-Br (4c, e) and a double bromine at 3,5-positions with a single methoxy group at 2-position (4n), of phenyl ring, and, to a lesser extent, other pyran derivatives with monoihalogenated (4a, b, d, f), dihalogenated (4 g, h, j, l) or trisubstituent phenyl ring (4o, p, q). Furthermore, compounds 4b-e, g, i, j, m, and n showed negligible activity against the two normal cell lines, HFL-1 and WI-38. Moreover, compound 4 g exhibited the strongest antimicrobial activity among the other pyran derivatives (4a-f, g-q) when compared to Ciprofloxacin. The MIC was assessed and screened for compound 4 g, revealing bactericidal effects. Lastly, SAR and molecular docking were studied. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) represent a new type of crystalline porous polymers that possess pre‐designed skeletons, uniform nanopores, and ordered π structure. These attributes make them well‐suited for the design of light‐emitting materials. However, the majority of COFs exhibits poor luminescence due to aggregation‐caused quenching (ACQ), resulting from the strong interaction between adjacent layers. To break the limitation, the building units with three methoxy groups on the walls are used to construct TM‐OMe‐EBTHz‐COF, which suppresses the ACQ effects to improve light‐emitting activity of COF. The TM‐OMe‐EBTHz‐COF exhibits a notable emission of yellow‐green luminescence in the solid state, with a remarkably high absolute quantum yield of 21.1%. The methoxy groups and hydrazine linkage form three coordination sites, contributing to excellent performance in metal ions sensing. The TM‐OMe‐EBTHz‐COF demonstrates high sensitivity and selectivity to Fe3+ ion. Importantly, the low detection limit is below 150 nanomolar, ranking it among the best‐performing Fe3+ sensor systems. [ABSTRACT FROM AUTHOR]

The rational design of covalent organic frameworks (COFs) with hydrochromic properties is of significant value because of the facile and rapid detection of water in diverse fields. In this report, we present a thiazole-linked COF (TZ-COF-6) sensor with a large surface area, ultrahigh stability, and excellent crystallinity. The sensor was synthesized through a simple three-component reaction involving amine, aldehyde, and sulfur. The thiazole and methoxy groups confer strong basicity to TZ-COF-6 at the nitrogen sites, making them easily protonated reversibly by water. Therefore, TZ-COF-6 displayed color change visible to the naked eye from yellow to red when protonated, along with a red shift in absorption in the ultraviolet-visible diffuse reflectance spectra (UV-vis DRS) when exposed to water. Importantly, the water-sensing process was not affected by polar organic solvents, demonstrating greater selectivity and sensitivity compared to other COF sensors. Therefore, TZ-COF-6 was used to detect trace amounts of water in organic solvents. In strong polar solvents, such as N,N-dimethyl formamide (DMF) and ethanol (EtOH), the limit of detection (LOD) for water was as low as 0.06% and 0.53%, respectively. Even after 8 months of storage and 15 cycles, TZ-COF-6 retained its original crystallinity and detection efficiency, displaying high stability and excellent cycle performance. [ABSTRACT FROM AUTHOR]

In this work, the geometrical, optical, and phosphorescence properties of four complexes with general formula [dRpypy—C(OCH3)R′—dRpypy]Pt, with Pt-1 (R = F, R′ = methyl), Pt-2 (R = F, R′ = hexyl), Pt-3 (R = methoxy, R′ = methyl) and Pt-4 (R = methoxy, R′ = hexyl), were studied using the B3PW91 and TD-B3PW91 methods. The effect of the double substitution R and R′ on the electronic properties of the four complexes has been investigated. Replacing the two fluorine atoms with the two methoxy groups modifies the shape of the UV–vis spectra and red shift the phosphorescence spectra, while the substituents on the linker R′ do not induce changes in both absorption and phosphorescence spectra. Normal modes involved in the vibronic structure were identified and analyzed using adiabatic Hessian approaches according to the Franck–Condon approximation. The computed phosphorescence wavelengths agree with the observed ones and indicate that the fluorinated complexes exhibit a bright light blue color, while the methoxy complexes display a light spring green color. Further, temperature effects on simulated phosphorescence spectra were studied. [ABSTRACT FROM AUTHOR]

Cancer is a perilous life-threatening disease, and attempts are constantly being made to create multinuclear transition metal complexes that could lead to the development of potential anticancer medications and administration procedures. Hence, this work aims to design, synthesize, characterize, and assess the anticancer efficacy of ruthenium p-cymene complexes incorporating N,N′-bis(4-substituted benzoyl)hydrazine ligands. The formation of the new complexes (Ru2H1–Ru2H3) has been thoroughly established by elemental analysis, and FT-IR, UV-vis, NMR, and HR-MS spectral techniques. The solid-state molecular structures of the complexes Ru2H1 and Ru2H3 have been determined using the SC-XRD study, which confirms the N, O, and Cl-legged piano stool pseudo-octahedral geometry of each ruthenium(II) ion. The stability of these complexes in the solution state and their lipophilicity profile have been determined. Furthermore, the title complexes were tested for their in vitro anticancer activity against cancerous H460 (lung cancer cells), SkBr3 (breast cancer cells), HepG2 (liver cancer cells), and HeLa (cervical cancer cells) along with non-cancerous (HEK-293) cells. The IC50 results revealed that complex Ru2H3 exhibits potent activity against the proliferation of all four cancer cells and outscored the effect of the standard metallodrug cisplatin. This may be attributed to the presence of a couple of lipophilic electron-donating methoxy groups in the ligand scaffold and also the ruthenium(II) p-cymene motifs. Advantageously, all the complexes (Ru2H1–Ru2H3) displayed cytotoxic specificity only towards cancerous cells by leaving the off-target non-cancerous cells undamaged. Acridine orange/ethidium bromide (AO/EB) staining, Hoechst 33342, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS) staining assays were used to investigate the apoptotic pathway and ROS levels in mitochondria. The results of western blot analysis confirmed that the complexes triggered apoptosis through an intrinsic mitochondrial pathway by upregulating Bax and downregulating Bcl-2 proteins. Finally, the extent of apoptosis triggered by the complex Ru2H3 was quantified with the aid of flow cytometry using the Annexin V-FITC/propidium iodide (PI) double-staining technique. [ABSTRACT FROM AUTHOR]

Two derivatives of phenyl pyrimidine as acceptor unit and triphenylamino or 4,4′-dimethoxytriphenylamino donor groups were designed and synthesized as emitters for organic light-emitting diodes (OLEDs) aiming to utilize triplet excitons in the electroluminescence. Thermogravimetric analysis revealed high thermal stability of the compounds with 5% weight loss temperatures of 397 and 438 °C. The theoretical estimations and photophysical data show the contributions of local excited and charge transfer states into emission. The addition of the methoxy groups led to the significant improvement of hole-transporting properties and the bathochromic shift of the emission from blue to green-blue spectral diapason. It is shown that mixing of the compounds with the organic host results in facilitation of the delayed emission. The singlet–triplet energy splitting was found to be too big for the thermally activated delayed fluorescence. No thermal activation of the long-lived emission was detected. No experimental evidence for triplet–triplet annihilation and room temperature phosphorescence were detected making the hot exciton mechanism the most probable one. The OLEDs based on the compounds reached the maximum external quantum efficiency of up to 10.6%. [ABSTRACT FROM AUTHOR]

This article provides a comprehensive overview of synthetic approaches to gliflozins, a class of drugs used to treat diabetes mellitus. It discusses different types of diabetes, management strategies, and various therapeutic agents available. The article focuses on the synthesis of specific gliflozins, highlighting different routes and their yields. The information presented is valuable for researchers studying diabetes and the development of antidiabetic drugs. It also mentions the approval and effectiveness of certain gliflozins in the treatment of diabetes. [Extracted from the article]

This document is a scientific research article that discusses the synthesis and potential biological activities of naphthoquinone-fused glycohybrids. The researchers designed a method to synthesize these compounds and obtained them in good yields. They also conducted experiments to evaluate the potential of these compounds as inhibitors of the IRAK1 catalytic site, which could have implications for anti-inflammatory and anticancer therapies. The document provides detailed experimental procedures and results for the synthesis and characterization of various compounds, as well as information on ligand-protein interaction studies using docking methods. The authors acknowledge the support and facilities provided by Banaras Hindu University and Jawaharlal Nehru University. [Extracted from the article]

Type 2 diabetes is common and involves α‐glucosidase inhibition to regulate glucose. We synthesized twenty E‐arylidene steroids with hydroxy and methoxy groups on the aromatic ring. Compounds 3 a, 5 a, 5 b, and 5 d showed notable inhibition, with IC50 values ranging from 1.84±0.28 to 9.25±2.53 μM. Key features for bioactivity include ortho methoxy and α‐hydroxy. Various inhibition mechanisms were observed. In silico studies elucidate the possible binding modes of E‐arylidene steroids, confirming their enzymatic mechanisms of non/un‐competitive inhibitors. Allosteric site 2 emerges as a potential binding site for compounds 3 a, 5 a, and 5 b. Compound 5 d holds promise as a potent α‐glucosidase inhibitor compared to acarbose at the orthosteric receptor binding site. [ABSTRACT FROM AUTHOR]

Lignin represents the largest aromatic carbon resource in plants, holding significant promise as a renewable feedstock for bioaromatics and other cyclic hydrocarbons in the context of the circular bioeconomy. However, the methoxy groups of aryl methyl ethers, abundantly found in technical lignins and lignin‐derived chemicals, limit their pertinent chemical reactivity and broader applicability. Unlocking the phenolic hydroxyl functionality through O‐demethylation (ODM) has emerged as a valuable approach to mitigate this need and enables further applications. In this review, we provide a comprehensive summary of the progress in the valorization of technical lignin and lignin‐derived chemicals via ODM, both catalytic and non‐catalytic reactions. Furthermore, a detailed analysis of the properties and potential applications of the O‐demethylated products is presented, accompanied by a systematic overview of available ODM reactions. This review primarily focuses on enhancing the phenolic hydroxyl content in lignin‐derived species through ODM, showcasing its potential in the catalytic funneling of lignin and value‐added applications. A comprehensive synopsis and future outlook are included in the concluding section of this review. [ABSTRACT FROM AUTHOR]