Amide Groups Research Articles

Metal Ion-Induced Acid Hydrolysis Strategy for the One-Step Synthesis of Tough and Highly Transparent Hydrolyzed Polyacrylamide Hydrogels.

Polyacrylamide (PAM) hydrogel is hard to enhance through coordination bonds because amide groups rarely coordinate with metal ions strongly in an aqueous solution. It is known that the aqueous solution of ZrOCl2.8H2O can be strongly acidic depending on its concentration. Consequently, through a facile one-step metal ion-induced acid hydrolysis strategy (MIAHS), tough and highly transparent hydrolyzed PAM physical hydrogels are prepared by using ZrOCl2.8H2O in this work. The formation of the partially hydrolyzed PAM physical hydrogels elucidates that the side reaction of imidization during common acid hydrolysis of PAM can be perfectly overcome because the structure of the Zr(IV) ion and its interaction with amide groups promote selective acidic hydrolysis from amide to carboxyl groups. Compared to most coordination cross-linked hydrogels, which need at least two-step fabrication, the hydrolyzed PAM hydrogel via MIAHS can be obtained by one-step synthesis due to the weak interaction between amide groups and Zr(IV). The obtained PAM hydrogel cross-linked by hydrogen bonds and coordination bond between Zr(IV) and carboxyl is a multibond network (MBN) and can achieve hierarchical energy dissipation, which exhibits excellent mechanical properties (tensile strength of 3.15 MPa, elongation at break of 890%, and toughness of 17.0 MJ m-3), high transparence (transmittance of 95%), and outstanding conductivity (5.6 S m-1) at water content of 80 wt %. The high gauge factor (from 2.24 to 12.8 as the strain increases from 0 to 400%) endows the hydrolyzed PAM hydrogels with promising application as strain sensors. Furthermore, in addition to ZrOCl2.8H2O, the fact that various hydrolyzable compounds of Ti(IV), Zr(IV) Hf(IV), and Sn(IV) can also fabricate tough hydrolyzed PAM hydrogels verifies the universality of MIAHS. Therefore, the simple, efficient, and universal MIAHS will shed new light on preparing functional PAM-based hydrogels.

Transition Metal‐Free One‐Pot Approach: Regioselective Synthesis of Pyrrolo[3,4‐b]quinolin‐1‐one Derivatives from o‐Alkynylquinoline‐3‐carbonitriles

A KOtBu‐promoted robust strategy has been described for the regioselective synthesis of pyrrolo[3,4‐b]quinolin‐1‐one and naphthyridin‐1(2H)‐one derivatives from o‐alkynylquinolinecarbonitriles in good to excellent yields. The reaction proceeds through in‐situ transformation of nitrile moiety into amide group followed by the selective C‐N bond formation via a 5‐exo‐dig or 6‐endo‐dig annulation reaction. Among the synthesized derivatives, 6‐endo‐dig naphthyridin‐1(2H)‐ones displayed good photophysical properties. The present approach is superior to other established methodologies owing to avoiding use of transition metals and column chromatographic purification and affording the products in high yields. Additionally, the current methodology provides several additional advantages like one‐pot operation, high atom economy, broad substrate scope and step‐economical process.

Experimental and theoretical study of novel polyamine bis(nitrophenylureylbenzamide) receptors with anion and cation interaction capacity

In this work the interaction of three new heterotopic polyamine bis(nitrophenylureylbenzamide) receptors (R = 3A-3C) with anions (A) and cations (M) was analyzed by UV–Vis spectroscopy and theoretical calculations. These receptors are highly pre-organized and form supramolecular complexes R-A at different ratios depending on the anion characteristics (1:1, 2:1, 3:1 and 4:3). The calculated log K values based on UV–Vis absorbance profiles and the structural information obtained from geometry optimizations using Density Functional Theory indicate strong stability in these complexes due to multiple intermolecular interactions between both species. Changes in the absorption band of receptors evidence the interaction with metallic ions forming complexes R-M (1:1) and the theoretical calculations predict the coordination with polyamine and amide groups adopting an aza-crown type conformation surrounding the Cu or Zn atoms. The subsequent formation of ternary complexes R-M-A with acetate showed different spectral changes for R-Cu and R-Zn ligands. The spectral changes with R-Cu ligands allowed to identified and calculated log K values for R-Cu-A and R-Cu-A2 complexes. Moreover, the optimized structures for R-Cu-A and R-Cu-A2 complexes show the coordination of one acetate ion with the metal center and a subsequent interaction of a second acetate with the urea groups in agreement with the experimental results.

Type of pectin affects the functionality of potato protein-pectin conjugates in emulsions

This study investigated the effect of the molecular structure of pectin on conjugate formation and its functionality in plant protein-based emulsions. For this purpose, high-methoxylated, low-methoxylated, amidated citrus pectin and their mixtures with potato protein were vacuum-dried at defined process conditions. The change in free amino groups, colour and molecular weight distribution assessed conjugation. The side reaction, such as pectin degradation, was monitored by the degree of methoxylation, galacturonic acid content and intrinsic viscosity. In addition, FT-IR and hydrophobicity measurements were performed to determine the changes in chemical structure due to the occurring reactions. The ζ-potential, solubility and oil droplet size reflected the functionality of the conjugated samples.The results confirm that, apart from the conjugation of protein and pectin, where the most significant decrease in free amino groups was obtained with an increasing degree of methoxylation or presence of amide groups, undesirable degradation of pectin occurring, resulting in a broad molecular weight distribution of the conjugate samples. The conjugate formation was the highest with amidated pectin. The FT-IR measurements confirmed the formation of Maillard conjugates. The FT-IR spectra showed a decrease in the intensity signals of amide I and amide II and the formation of new C–N bond maxima. In addition, the conjugation caused the shift of the protein's isoelectric point to the acidic environment, resulting in higher solubility and improved emulsion stability at the isoelectric point of the protein.Regarding emulsion stability, the conjugates with amidated pectin performed best and achieved the narrowest oil droplet size distribution over a wider pH range. Emulsion-stabilising properties of conjugates with high- and low-methoxylated pectin differed only slightly. To better understand the underlying mechanisms for emulsion stabilisation, future research will focus on the interfacial properties of the conjugates as determined by interfacial shear rheology and pendant drop analysis.

Discovery of novel benzimidazole derivatives as selective and reversible monoamine oxidase B inhibitors for Parkinson's disease treatment

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta. The development of novel scaffolds for human monoamine oxidase B (hMAO-B) inhibitors with reversible properties represents an important strategy to improve the efficacy and safety for PD treatment. In the current work, we have devised and assessed two innovative derivative series serving as hMAO-B inhibitors. These series have utilized benzimidazole as a scaffold and strategically incorporated a primary amide group, which is recognized as a pivotal pharmacophore in subsequent activity screening and reversible mode of action. Among these compounds, 16d has emerged as the most potent hMAO-B inhibitor with an IC50 value of 67.3 nM, comparable to safinamide (IC50 = 42.6 nM) in vitro. Besides, 16d demonstrated good selectivity towards hMAO-B isoenzyme with a selectivity index over 387. Importantly, in line with the design purpose, 16d inhibited hMAO-B in a competitive and reversible manner (Ki = 82.50 nM). Moreover, 16d exhibited a good safety profile in both cellular and acute toxicity assays in mice. It also displayed ideal pharmacokinetic properties and blood-brain barrier permeability in vivo, essential prerequisites for central nervous system medicines. In the MPTP-induced PD mouse model, 16d significantly alleviated the motor impairment, especially muscle relaxation and motor coordination. Therefore, 16d, serving as a lead compound, holds instructive significance for subsequent investigations regarding its application in the treatment of PD.

Synthesis of linear polyesters bearing amino groups via lipase-catalyzed polymerization of N-protected monomer and deprotection

Linear biodegradable polyesters with a controlled number of side chains of amino groups have been synthesized. Such polyesters with a large number of amino side groups can be conjugated with a wide variety of functional molecules to obtain multi-functional biodegradable polyesters. In this study, poly(1,3-propylene-co-2-amino-1,3-propylene) adipate) (P(P-co-AP)A) was synthesized by enzymatic polymerization of divinyl adipate, 1,3-propanediol, and N-Boc-2-amino-1,3-propanediol (BocAPDO), and subsequent deprotection under strong acidic conditions. The mild reaction conditions and the specificity of the enzymatic polymerization could effectively inhibit side reactions, while the protecting groups of the monomers prevented polymer branching from the amino groups. It was found that the introduction rates of BocAPDO in the polymers could be well-controlled as the feeding rates changed from 0 to 100 mol%. After the deprotection and desalting, the ester groups in the main chain gradually converted into amide groups by intramolecular ester aminolysis at room temperature for a few days due to nucleophilic free amino groups. It was also found that the synthesized functional copolymers were all amorphous, since the random component of amino groups disrupted the crystallinity of poly(1,3-propylene adipate) (PPA). The glass transition temperature gradually increased with the increase in the content of 2-amino-1,3-propylene adipate (APA), eventually reaching −0.4 °C at the APA content of 100 mol% due to the intermolecular hydrogen bonding. Moreover, P(P-co-AP)A shows high hygroscopicity, where 3.9 wt% and 8.1 wt% of water were absorbed in the polymers with the APA contents of 50 and 100 mol%, respectively, when left in air at 60–70 % humidity for 6 h. Thus, the hydrophilicity dramatically improved with the increase in the APA content, eventually resulting in the acquisition of water solubility. The model post-polymerization modification using butyric acid was also conducted, and it was confirmed that carboxylic acids could be conjugated to the polymers by simple condensation reaction. Since polymerization of functional monomers is generally susceptible to the polarity of metal catalysts, the mild and selective reaction employed in this study could realize a higher content of various functional groups in the side chains of polyesters leading to a newly designed multi-functional polyester.

Analyte protectant approach to protect amide-based synthetic cannabinoids from degradation and esterification during GC–MS analysis

The forensic analysis of amide-based synthetic cannabinoids (SCs) in seized materials is routinely performed using gas chromatography-mass spectrometry (GC–MS); however, a major challenge associated with GC–MS is the thermolytic degradation of substances with sensitive functional groups. Herein, we report the comprehensive thermal degradation and ester transformation of amide-based SCs, such as AB-FUBINACA, AB-CHMINACA, and MAB-CHMINACA, during GC–MS analysis and their treatment with analyte protectants (APs). These SCs were found to undergo thermolytic degradation during GC–MS in the presence of non-alcohol solvents. Using methanol as an injection solvent resulted in the conversion of the amide group to an ester group, producing other SCs such as AMB-FUBINACA, MA-CHMINACA, and MDMB-CHMINACA. Degradant and ester product formation has been interpreted as the adsorption of target SCs on glass wool via hydrogen bonding interactions between the active silanol and amide groups of the SCs, followed by an addition and/or elimination process. The factors found to influence the thermal degradation and/or esterification of the amide functional group include residence time, activity of glass wool, and injection volume. This report presents the fragmentation patterns of all compounds that were produced by degradation and esterification. Using 0.5 % sorbitol (AP) in MeOH as an injection solvent resulted in complete protection and improvement of the chromatographic shape of the compounds. This method has been successfully confirmed in terms of sensitivity, linearity, accuracy, and precision for standard solutions and tablet extraction using 0.5 % sorbitol in MeOH. Using AP increased the sensitivity by ten times or more compared to the use of only MeOH. The limit of detection for all analytes was determined as 25 ng/mL, and the calibration curves were linear over the concentration range of 50–2000 ng/mL. The values of accuracy error were below 11 %, and precision was less than 13 %. The effects of phytochemicals of herbal products, tablet ingredients, and biological matrices on the degradation and/or esterification and APs performance have also been evaluated in this work.

On the solubility of azodicarbonamide in water/DMSO mixtures: an experimental and computational study.

This work aims at studying why azodicarbonamide (ADCA), a formally apolar compound with good hydrogen bond (HB) acceptors, is soluble only in polar aprotic solvents like dimethyl sulfoxide (DMSO) but not in water. Solubility measurements, as well as quantum mechanical and classical molecular dynamics simulations, were employed to tackle the problem. We found that in the liquid phase a polar conformer of ADCA (µ = 8.7 D), unreported to date, is favoured under the enthalpic drive provided by a highly polar solvent. At the same time, the very high hydrogen bond propensity of water with itself prevents this solvent from providing an effective hydrogen bond-mediated solvation. Solvents bearing good HB acceptors, while lacking strong HB donors, contribute to further stabilizing solute-solvent adducts through weak and fluxional HBs that involve the amide groups of ADCA. Implications for the solubility of ADCA down to µM concentrations were evaluated, also with the aid of classical simulations of solution nanodroplets.

Influence of polar solvent in formation and organic solvent separation performance of novel fluorine-containing polyamide membranes

Polyamide thin film composite (PA-TFC) membranes have shown great potential in organic solvent separations. However, the intrinsic polar feature of the amide group limits their permeability to specific solvents, such as nonpolar solvents. In this study, we used a fluorine-containing monomer [4,4′-oxybis(3-(trifluoromethyl)aniline), OTFA] to conduct interfacial polymerization (IP) with trimesoyl chloride, resulting in the fabrication of novel PA-TFC membranes with permeability to both polar and nonpolar solvents. Interestingly, by simply adjusting the composition of OTFA solvents [DMF and DMF/water (1:1, v: v)], we obtained two PA-TFC membranes (OTFA-D and OTFA-DH, respectively) featuring completely different structures and surface properties, including PA layer thickness, water contact angle, surface element composition, surface charge, and polarity. Due to their distinct structures and surface features, the two membranes exhibited different performances in organic solvent nanofiltration (OSN). The OTFA-DH membrane showed higher permeability to polar solvents (e.g., methanol), while the OTFA-D membrane was more permeable to nonpolar solvents (e.g., toluene). The mechanism on the formation of the two PA layers was clarified by combining the experimental results with the molecular dynamics simulations. The significantly different interfacial properties and monomer diffusion during IP led to the substantial differences in the formation of the PA network. This work provides a strategy to fabricate tailored PA-TFC membranes for various OSN scenarios by simply adjusting the solvent compositions.

Isolation and characterization of chitosan from black soldier fly exuviae

Abstract Black Soldier Fly (BSF) cultivation leaves waste in the form of exuviae which is a new source of chitin and chitosan biopolymers, which can be used for various applications. This study aims to isolate and characterize chitosan from BSF exuviae. Chitosan isolation includes demineralization, deproteination, depigmentation, and deacetylation stages. The results showed that the chitosan in this study was in powder form, odorless, brownish white in color, soluble in 2% acetic acid, 12.46% yield, 88% degree of deacetylation, and the presence of an absorption band in the wave number region of 3443 cm-1 indicating the presence of hydroxyl groups and absorption in the wave number region of 1637 cm-1 which indicates the presence of amide groups based on the FTIR spectrum. The quality of the chitosan produced meets the quality standards of chitosan according to SNI No.7949-2013.

Structural characterization of Aspalatus linearis polysaccharide and its improving effect on acute alcoholic liver injury.

Polysaccharides from natural sources can regulate the composition of intestinal flora through the "gut-liver axis" pathway, potentially ameliorating alcoholic liver injury. Aspalathus linearis, also known as rooibos, is one such natural product that has shown promise in this regard. This study looked at the structural properties of A. linearis polysaccharide (ALP) and how well it would work to treat acute alcoholic liver impairment. This study looks at the composition of monosaccharides, functional groups, and molecular weight (Mw) of a newly discovered water-soluble polysaccharide, named ALP. The polysaccharide is composed of pyranose rings, amide groups, and sulfate groups linked by β-glycosidic linkage. It has a relative Mw of 4.30×103kDa and is composed of glucose, rhamnose, and some other monosaccharides. The study found that treating mice with the model of acute alcoholic liver disease with ALP could alleviate pathological symptoms, inhibit the release of inflammatory cytokines, and suppress indicators of oxidative stress. Experiments have shown that different doses of ALP can activate the P4502E1/Keap1-Nrf2-HO-1 signaling pathway. The regulation of inflammatory factors and downstream antioxidant enzymes occurs as a result. Based on these data, it is likely that ALP protects the liver via the "gut-liver axis" pathway by reducing oxidative stress-related damage, inflammation, and alcohol-related alterations to the gut microbiome. The results indicate that ALP mitigates injury caused by oxidative stress, inflammatory responses, and changes in the gut microbiota induced by alcohol through the "gut-liver axis" pathway, which provides protection to the liver. This provides preliminary evidence for the development of related drugs. PRACTICAL APPLICATION: Researchers extracted a polysaccharide from fresh leaves of Auricularia auricula. The polysaccharide was purified and determined to have a predominantly homogeneous molecular weight. An acute alcoholic liver damage mouse model was established, and it was concluded that the polysaccharide could ameliorate liver injury in mice through the "gut-liver axis" pathway. This novel polysaccharide can be used as an additive to develop functional foods with beneficial effects, which can positively impact the daily maintenance of consumers.

Quantitative entropy-enthalpy compensation in intraprotein interactions from model compound data.

Many small globular proteins exist in only two states-the physiologically relevant folded state and an inactive unfolded state. The active state is stabilized by numerous weak attractive contacts, including hydrogen bonds, other polar interactions, and the hydrophobic effect. Knowledge of these interactions is key to understanding the fundamental equilibrium thermodynamics of protein folding and stability. We focus on one such interaction, that between amide and aromatic groups. We provide a statistically convincing case for quantitative, linear entropy-enthalpy compensation in forming aromatic-amide interactions using published model compound transfer-free energy data.

Bisphenol A sorption on commercial polyvinyl chloride microplastics: Effects of UV-aging, biofilm colonization and additives on plastic behaviour in the environment.

Chemical additives are important components in commercial microplastics and their leaching behaviour has been widely studied. However, little is known about the potential effect of additives on the adsorption/desorption behaviour of pollutants on microplastics and their subsequent role as vectors for pollutant transport in the environment. In this study, two types of commercial polyvinyl chloride (PVC1 and PVC2) microplastics were aged by UV irradiation and biotic modification via biofilm colonization to investigate the adsorption and desorption behaviour of bisphenol A (BPA). Surface cracks and new functional groups (e.g., O–H) were found on PVC1 after UV irradiation, which increased available adsorption sites and enhanced H‒bonding interaction, resulting in an adsorption capacity increase from 1.28 μg/L to 1.85 μg/L. However, the adsorption and desorption capacity not showed significant changes for PVC2, which might be related to the few characteristic changes after UV aging with the protection of light stabilizers and antioxidants. The adsorption capacity ranged from 1.28 μg/L to 2.06 μg/L for PVC1 and PVC2 microplastics, and increased to 1.62 μg/L—2.95 μg/L after colonization by biofilms. The increased adsorption ability might be related to the N–H functional group, amide groups generated by microorganisms enhancing the affinity for BPA. The opposite effect was observed for desorption. Plasticizers can be metabolized during biofilm formation processes and might play an important role in microorganism colonization. In addition, antioxidants and UV stabilizers might also indirectly influence the colonization of microorganisms’ on microplastics by controlling the degree to which PVC microplastics age under UV. The amount of biomass loading on the microplastics would further alter the adsorption/desorption behaviour of contaminants. This study provides important new insights into the evaluation of the fate of plastic particles in natural environments.

Mechanistic deduction of gallium(III) extraction using halogenated secondary amides: Spectroscopic interpretation

Secondary amides act as bifunctional compounds to extract metal anionic species due to the presence of N–H hydrogen and protonated carbonyl oxygen atoms. To exclude the latter function with stronger interaction and less extraction selectivity for metal anionic species, two secondary amide compounds with halogen atoms, namely N-(2-ethylhexyl)-2,2,2-trichloroacetamide as TCAA and N-(2-ethylhexyl)-2,2,2-tribromoacetamide as TBAA, have been synthesised to investigate the efficiency and mechanism of Ga(III) extraction for comparison with N-(2-ethylhexyl)-2,2,2-trifluoroacetamide (TFAA). The 1H NMR spectroscopy results indicated the absence of proton extraction from the carboxylic oxygen atoms of both halogen-containing amides at sufficiently high concentrations of HCl. The three amides exhibited preferential extraction of Ga(III) compared to other metals in highly acidic media. A slope analysis was conducted to assess the stoichiometry for the extraction of Ga(III). The FT-IR and 1H NMR spectroscopies were employed to elucidate the extraction mechanism of GaCl4– using TCAA and TBAA. Therefore, the hydrogen atoms of the N–H group of both amides, with extremely weak δ+ nature, exhibited a distinct extractive preference for anionic GaCl4–. Following the forward extraction, Ga(III) was effectively separated from the organic phase through stripping with distilled water. The extraction efficiencies of GaCl4– among the three amides are not followed by the strength of electron-withdrawing nature of halogen atoms, but the strength of intra- or intermolecular interactions of the amides. This argument was substantiated by calculations using density functional theory (DFT).

Disazo disperse dyes crosslinked with varied characteristic groups: Their synthesis, characterization, and application on polyester fabrics

We previously synthesized a group of carbamate-linked disazo disperse dyes that showed excellent fastness properties on polyester fabric by using the thermosol dyeing process. However, the color yield of the dyed fabric was not sufficiently high to be accepted by users, especially when using a high-temperature dyeing process. To further optimize the structures of disazo disperse dyes and observe the effect of the linking groups on the dyeing properties, in this work, we used p-phenylene diisocyanate or terephthaloyl chloride as crosslinking agents and aniline derivatives containing hydroxyl or amino groups as reactants to synthesize four disazo disperse dyes containing various characteristic groups, including ester, carbamate, amide, and urea groups. The structures of these new dyes were characterized by nuclear magnetic resonance, mass spectrometry, and Fourier-transform infrared spectroscopy analyses. The spectral properties in an N,N-dimethylformamide solvent were measured, the structural parameters of the dyes were calculated using the density functional theory method, and the dyeing properties were investigated by using high-temperature and thermosol dyeing processes, and also compared with these for the commercial dye, C·I.Disperse Red 153. The results showed that there were slight differences in the molar extinction coefficients and maximum absorbance wavelengths between the new dyes, but the effects of characteristic groups on the structural features and the dyeing properties of the new dyes were significant. The ester-linked dye (D1) had the highest color depth when a high-temperature process was used in the presence of 50 mL/L of methyl salicylate because of its highest ClogP (N-octanol/water partition coefficient) value, corresponding to its more hydrophobic nature, while all the other dyes produced lower color yields. When used in the thermosol dyeing process, the carbamate-linked dye (D2) yielded the highest color depth, followed by the ester-linked dye (D1) and amide-linked dye (D3), and the urea-linked dye (D4) produced the lowest color depth due to its highest hydrophilic properties. Finally, it was demonstrated that the new dyes had excellent color fastnesses except for the urea-linked dye (D4), which exhibited a slightly lower light fastness, While the commercial dye used as the control showed a relatively poor sublimation and light fastness although its color depth and chroma value performed slightly better than the new dyes as used by the thermosol dyeing process.

Design, synthesis and inhibition evaluation of novel chalcone amide α-glucosidase inhibitors.

Aim: The purpose of this study is to design and synthesize a series of novel chalcone amide α-glucosidase (AG) inhibitors (L1-L10) based on virtual screening and molecular dynamics (MD) simulation. Materials & methods: Target compounds (L1-L10) were synthesized from 2-hydroxyacetophenone and methyl 4-formylbenzoate. Results: In vitro activity test shows that most compounds have good AG inhibition. Specially, compound L4 (IC50=8.28±0.04μM) had the best inhibitory activity, superior to positive control acarbose (IC50=8.36±0.02μM). Molecular docking results show that the good potency of L4 maybe attributed to strong interactions between chalcone skeleton and active site, and the torsion of carbon nitrogen bond in amide group. Conclusion: Compound L4 maybe regard as a good anti-Type II diabetes candidate to preform further study.

An Allysine-Conjugatable Probe for Fluorogenically Imaging Fibrosis.

Allysine, a pivotal biomarker in fibrogenesis, has prompted the development of various radioactive imaging probes. However, fluorogenic probes targeting allysine remain largely unexplored. Herein, by leveraging the equilibrium between the nonfluorescent spirocyclic and the fluorescent zwitterionic forms of rhodamine-cyanine hybrid fluorophores, we systematically fine-tuned the environmental sensitivity of this equilibrium toward the development of fluorogenic probes for fibrosis. The trick lies in modulating the nucleophilicity of the ortho-carboxyl group, which is terminated with a hydrazide group for allysine conjugation. Probe B2 was developed with this strategy, which featured an N-sulfonyl amide group and exhibited superior fibrosis-to-control imaging contrast. Initially presenting as nonfluorescent spirocyclic aggregates in aqueous solutions, B2 displayed a notable fluorogenic response upon conjugation with protein allysine through its hydrazide group, inducing deaggregation and switching to the fluorescent zwitterionic form. Probe B2 outperformed the traditional Masson stain in imaging contrast, achieving an about 260-2600-fold ratio for fibrosis-to-control detection depending on fibrosis severity. Furthermore, it demonstrated efficacy in evaluating antifibrosis drugs. Our results emphasize the potential of this fluorogenic probe as an alternative to conventional fibrosis detection methods. It emerges as a valuable tool for antifibrosis drug evaluation.

Investigations of the carbonization process of hybrid polymer microspheres using the TGA-EGA method: assessment of the impact of sulphanilic acid on the process

The TGA-EGA technique was used to study the influence of sulphanilic acid (SA) on the carbonisation process of the hybrid terpolymeric precursors composed of methacrylamide, divinylbenzene, and trimethoxyvinylsilane. The pristine polymers were impregnated with saturated solution of SA, dried, and carbonized at 600 °C under N2 atmosphere. The characteristic properties of both the pristine hybrid polymers and the resulting carbons were based on FTIR, Raman, and PXRD analyses, which revealed the materials were composed of amorphous polymeric or carbon phase interpenetrated by silica/silicate disordered network. The porosimetric analysis showed the resulted carbons possessed homogeneous supermicropores with the average pore width of 0.7 nm and reduced number of mesopores compared to pristine precursors. From the TGA results, it was followed that impregnated polymers decomposed in two stages, instead of one like pristine precursors did. Moreover, IDT of impregnated polymers was reduced by about 100 °C, and their Tmax was increased by 2–5.5 °C. Their decomposition proceeded slower by 22–37% that caused increase in efficiency of the process by 10–48%. The EGA showed the decomposition of the impregnated precursors started from the degradation of the amide groups, then SA destruction took place, followed by further decomposition of the polymer. The studies led to the conclusion that SA had the protective effect on the surface of the carbonized polymers. During impregnation and thermal treatment, SA produced a deposit in pores of the precursors. This resulted in narrowing of the pore width, delaying and slowing down the polymer thermal decomposition process, as well as increasing its efficiency.

Direct Introduction of an Acetyl Group at the α‐Carbon Atom of an Arene Ring through an Amide Photo‐Fries Rearrangement upon Exposure to UV Light

AbstractWe employed an amide photo‐Fries rearrangement for the synthesis benzoheterocyclic compounds and found that direct acylation of the α‐carbon atom in an arene ring can occur upon exposure to ultraviolet (UV) light. In this reaction, the N‐acetyl group of amides underwent rearrangement to the α‐position across the bridgehead carbon atom under UV−C light. The reaction conditions were gentle and safe. Moreover, this reaction proves to be more convenient for selectively manipulating benzoheterocyclic compounds in comparison to traditional approaches involving Lewis acid catalysts or anionic reagents.

Comprehensive extraction study using N,N-dioctylthiodiglycolamic acid: effect of S donor on metal extraction.

Extraction ability of N,N-dioctylthiodiglycolamic acid (T-DODGAA), a soft-base sulfur donor ligand with an amide group and a carboxylic acid connected by a thioether chain, for 56 metal ions have been comprehensively investigated and compared with that of N,N-dioctyldiglycolamic acid (DODGAA) with an etheric oxygen atom, a hard-base donor. The acid dissociation constant (pKa) of the thiodiglycolamic acid framework was determined to be 3.71 ± 0.06 in water (0.1M LiCl, 25°C) by potentiometric titration, indicating that T-DODGAA is a slightly weaker acid than DODGAA (pKa = 3.54 ± 0.03). T-DODGAA can quantitatively extract various metal ions from the 56 metal ions into the organic phase (isooctane) through a proton-exchange reaction. T-DODGAA provided higher extraction performance than DODGAA for Hf(IV), Cr(III), Fe(III), Ni(II), Cu(II), Pd(II), Ag(I), Au(III), Hg(II), Al(III), and Ga(III), especially for soft metal ions. Furthermore, to demonstrate the practical feasibility of T-DODGAA for hydrometallurgy and metal recycling, we performed selective separation tests of rare metal ions such as Sc(III), Ni(II), Co(II), Pd(II), Au(III), In(III), and Ga(III) in metal-mixed extraction systems.