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AbstractFree or conjugated aromatic/phenolic acids arise from the diet, endogenous metabolism of catecholamines (adrenaline, noradrenaline, dopamine), protein (phenylalanine, tyrosine), pharmaceuticals (aspirin, metaprolol) plus gut microbiota metabolism of dietary (poly)phenols and undigested protein. Quantitative data obtained with authentic calibrants for 112 aromatic/phenolic acids including phase-2 conjugates in human plasma, urine, ileal fluid, feces and tissues have been collated and mean/median values compared with in vitro bioactivity data in cultured cells. Ca 30% of publications report bioactivity at ≤1 μmol/L. With support from clinical studies, it appears that the greatest benefit might be produced in vascular tissues by C6–C3 metabolites, including some of gut microbiota origin and some phase-2 conjugates, 15 of which are 3′,4′-disubstituted with multiple sources including caffeic acid and hesperetin, plus one unsubstituted and two mono-substituted examples which can originate from protein. There is an unexamined potential for synergy. Free-living and washout plasma data are scarce. Some metabolites have been overlooked, notably phenyl-lactic, phenyl-hydracrylic and phenyl-propanoic acids, especially those from amino acids plus glycine, hydroxy-glycine and glutamine conjugates. Phenolic acids and conjugates from multiple sources exhibit biological activities, some of which are likely relevant in vivo and link to biomarkers of health. Further targeted studies are justified. [ABSTRACT FROM AUTHOR]

We conducted a simultaneous field study of PM 2.5 -bound particulate polycyclic aromatic hydrocarbons (PAHs) and aromatic acids (AAs) in a polluted city Zhengzhou to explore the concentration, sources and potential conversion pathways between PAHs and AAs in different seasons. The average concentrations of PM 2.5 , 28PAHs and 8AAs during the sampling period were 77 µg/m3, 75 ng/m3, and 283 ng/m3 , respectively. The concentration of both 28PAHs and 8AAs were highest in winter and lowest in summer with ratios of 6.3 and 2.3, respectively. PAHs with 5–7 rings were the main components of PAHs (52%), followed by 4 rings PAHs (30%) and 2–3 rings PAHs (18%). According to the source appointment results obtained by positive matrix factorization, the main sources of PAHs were combustion and vehicle emissions, which account for 37% and 34%, respectively. 8AAs were divided into three groups, including four benzene dicarboxylic acids (B2CAs), three benzene tricarboxylic acids (B3CAs) and one benzene tetracarboxylic acid (B4CA). And interspecies correlation analysis with PM 2.5 source markers were used to investigate potential sources. Phthalic acid (o -Ph) was the most abundant specie of 8AAs (157 ng/m3, 55% of 8AAs), which was well correlated with sulfate. Meanwhile, B3CAs and B4CA were highly correlated with sulfate and weakly correlated with levoglucosan, suggesting that secondary formation was their main source. As logical oxidation products of PAHs, o -Ph and B3CAs showed good correlations with a number of PAHs, indicating possible photochemical oxidation pathway by PAHs. In addition, O 3 , NO 2 , temperature and relative humidity have positive effects on the secondary formation of B3CAs. [ABSTRACT FROM AUTHOR]

The oxidation of benzylic alcohols is an important transformation in modern organic synthesis. A plethora of photoredox protocols have been developed to achieve the aerobic oxidation of alcohols into carbonyls. Recently, several groups described that ultraviolet (UV) or purple light can initiate the aerobic oxidation of benzylic alcohols in the absence of an external catalyst, and depicted different mechanisms involving the photoinduction of •O2− as a critical reactive oxygen species (ROS). However, based on comprehensive mechanistic investigations, including control experiments, radical quenching experiments, EPR studies, UV–vis spectroscopy, kinetics studies, and density functional theory calculations (DFT), we elucidate here that HOO•, which is released via the H2O2 elimination of α-hydroxyl peroxyl radicals [ArCR(OH)OO•], serves as the real chain carrier for the autocatalytic photooxidation of benzylic alcohols. The mechanistic ambiguities depicted in the precedent literature are clarified, in terms of the crucial ROS and its evolution, the rate-limiting step, and the primary radical cascade. This work highlights the necessity of stricter mechanistic analyses on UV-driven oxidative reactions that involve aldehydes' (or ketones) generation. [ABSTRACT FROM AUTHOR]

A relatively green one-pot environmentally benign protocol has been developed for the smooth access of 5- (Substituted-phenyl)-[1,3,4]thiadiazole-2-amine derivatives. Present research involved the cyclocondensation response of substituted fragrant carboxylic acid and thiosemicarbazide under microwave irradiation with the usage of PEG-400 as a green catalyst. The protocol was found to be an easy, cheaper, and metallic-free green medium. The remarkable features of the present investigation are safe and environmentally benign, inexpensive, and use of nontoxic and non-volatile PEG-400 as a medium. The present study involved direct condensation of aromatic carboxylic acid with thiosemicarbazide in a minimum reaction time to obtain an excellent yield of thiadiazol-2-amines. [ABSTRACT FROM AUTHOR]

Low-molecular-weight aromatic acids (LWMAAs), a ubiquitous organic substance in natural systems, are important in controlling the environmental fate of potentially toxic metals. However, little is known about the effects of LWMAAs on the interactions between biochars and potentially toxic metals. Herein, the influences of three aromatic acids, including benzoic acid (BA), p-hydroxy benzoic acid (PHBA), and syringic acid (SA), on the adsorption of Cd2+ onto biochars generated at three different pyrolysis temperatures under acidic and neutral conditions were examined. Generally, the adsorption ability of biochars for Cd2+ improved with the increase of pyrolysis temperature, which was ascribed to the increased inorganic element contents (e.g., P, S, and Si) and aromaticity, increasing the complexation between mineral anions and metal ions, and the enhanced cation-π interaction. Interestingly, aromatic acids considerably inhibited the adsorption of Cd2+ onto biochars, which was mainly ascribed to multi-mechanisms, including competition of LWMAA molecules and metal ions for adsorption sites, the pore blocking effect, the weakened interaction between mineral anions and Cd2+ induced by the adsorbed aromatic acids, and the formation of water-soluble metal-aromatic acid complexes. Furthermore, the inhibitory effects of LWMAAs on Cd2+ adsorption intensively depended on the aromatic acid type and followed the order of SA > PHBA > BA. This trend was related to the differences in the physicochemical features (e.g., the octanol/water partition coefficient (log Kow) and molecular size) of diverse LMWAAs. The results of this study demonstrate that the effects of coexisting LMWAAs should not be ignored when biochars are applied in soil remediation and wastewater treatment. [ABSTRACT FROM AUTHOR]

The use of fatty and aromatic acids as green acyl donors for enzymatic kinetic resolution via esterification of 1-phenylethanol and 1-phenylpropan-2-ol was described. The impact of the presence of magnesium sulfate on both reactivity and selectivity of Candida rugosa lipase (CRL) was checked. The organic solvents, the medium dilution, and the temperature revealed as determinant parameters to achieve enantioselective esterification reactions. A significant impact of the use of magnesium sulfate was revealed on the enantioselectivity of the CRL in heptane during the resolution of 1-phenylethanol, using butyric and lauric acids as acyl donors. [ABSTRACT FROM AUTHOR]

Phenolic compounds and aromatic acids, as oxygenated aromatic compounds, can participate in photochemical reactions to form secondary organic aerosols (SOAs), and thus strongly impact climate and human health. In the present study, on‐site combustion experiments were conducted to determine primary emissions and secondary formation of phenolic compounds and aromatic acids released from burning of a variety of solid fuels using a potential aerosol mass‐oxidation flow reactor (PAM‐OFR). Emission factors (EFs) of phenolic compounds and aromatic acids from aged samples were 1.04 to 4.04 and 0.90 to 2.80 times those in the fresh PM2.5, respectively, implying significant amounts of these compounds produced from atmospheric aging processes. Substantially different emission profiles of phenolic compounds were observed between coal and biomass burning, with coal combustion mainly released single‐ring species (82%–86% in primary and 86%–89% in secondary emissions), while biomass burning released more two‐, three‐, and four‐ring species (59%–69% in primary and 50%–58% in secondary emissions). Aromatic acids emission profiles from coal and biomass burning also differed considerably, with biomass burning producing significantly higher (>2 times) abundance of dibasic acids than coal combustion, suggesting higher potential of producing additional ‐COOH group from biomass burning. Benzenediol, cresol, dimethylphenol, 1‐pyrenol, phenanthrenol, and hydroxylbenzonic acid were identified as SOA as they were mainly formed during simulated aging processes. Benzenediol acid/phenanthrenol was much lower from biomass (3.70 ± 1.29) than coal (62.7 ± 9.61), and these values remained stable after aging, suggesting this ratio being suitable as tracer for distinguishing different fuels combustion in source apportionment analysis. Plain Language Summary: Primary and photochemically aged phenolic compounds and aromatic acids emissions from 11 combustion scenarios covering different solid fuels and two types of stoves were investigated on‐site in rural northern China. Our results proved that aging processes could significantly increase EFs for both phenolic compounds and aromatic acids. Substantially different emission profiles of phenolic compounds and aromatic acids observed between coal and biomass combustion. During the aging processes, benzene, toluene, pyrene, phenanthrene, and benzoic acid reacted with OH to produce benzenediol, cresol, dimethylphenol, 1‐pyrenol, phenanthrenol, and hydroxylbenzonic acid, and these products could be used as SOA tracers. Our findings also indicated that several species ratios, including benzenediol acid/phenanthrenol, benzenediol acid/1,5‐dihydroxynaphthalene, benzenediol acid/1,8‐dihydroxynaphthalene, benzoic acid/2,3‐and 3,5‐dimethylbenzoic acid, and o‐, m‐, and p‐toluic acids/2,3‐and 3,5‐dimethylbenzoic acid, could be used as effective source tracers considering the stability of these ratios during aging processes and the differences in these ratios between different fuels. Key Points: Aging process for solid fuel primary emissions by reacting with OH produces significant amounts of phenolic compounds and aromatic acidsCoal combustion mainly releases single‐ring phenolic compounds, and biomass burning has a higher potential of producing additional ‐COOHMass ratio of Benzenediol acid/phenanthrenol is an ideal tracer due to its stability after aging process [ABSTRACT FROM AUTHOR]

Using reverse-phase high-performance liquid chromatography, some features of the chromatographic retention of polar aromatic acids (gallic, ferulic, benzoic, and salicylic) on hexadecylsilica gel from aqueous-acetonitrile eluents containing imidazolium ionic liquids (ILs) were studied. The following ILs were used: 1-butyl-3-methylimidazolium bromide [C4MIM][Br], 1-hexyl-3-methylimidazolium bromide [C6MIM][Br], 1-decyl-3-methylimidazolium bromide [C10MIM][Br], and 1-methyl-3-octylimidazolium bromide [MC8IM][Br]. The dependences of retention on the structure of imidazolium ILs and aromatic acids were studied. Based on the temperature dependences of the retention factor, the thermodynamic characteristics of the sorption process (standard enthalpy and entropy component) were calculated. The obtained thermodynamic characteristics of sorption were analyzed, and the influence of the structure of the IL and sorbate on their values was shown. The compensation relationships between the enthalpy and the entropy component of the sorption of the studied aromatic acids were analyzed. [ABSTRACT FROM AUTHOR]

A highly efficient ionic liquid catalyzed protocol has been investigated for the synthesis of 5-(4-substituted-phenyl)-1,3,4-thiadiazole-2-amine derivatives from the cyclocondensation of diversely substituted aromatic carboxylic acid and thiosemicarbazide by using recyclable N-methylpyridiniumtosylate as an ionic liquid. Highly efficient, inexpensive, solvent and metal free, high step and atom efficiency and excellent yield (95%–98%) are remarkable features of present protocol. [ABSTRACT FROM AUTHOR]

The increased interest in grapevines and their products, which are universal in terms of taste and healing properties, results from the diverse content of beneficial compounds that have a positive effect on the human body. The valuable chemical composition of grape seed oil, as well as the peel of both white and red grape varieties, supports the importance of using this product not only in food but also in other areas.

Aromatic organic acids are among the common environmental pollutants that enter the water with washouts from agricultural lands, wastewater from chemical and pharmaceutical industries. Taking into account the high toxicity of aromatic substances, the important task of water purification is the removal of their trace amounts. This problem can be solved by using chemically modified inorganic materials, such as silicas, which have high mechanical, chemical, hydrolytic, and radiation stability. Therefore, they do not lose their sorption capacity during long-term use and do not pollute water with sorbent degradation products. The purpose of this work is the synthesis of a sorption-active material for removal of toxic aromatic acids by chemical immobilization of β-cyclodextrin functional groups on an aerosilogel (highly dispersed type of amorphous silica). A β-cyclodextrin-containing aerosilogel was synthesized by two-stage liquid-phase chemical modification of hydroxylated silica surface. Using the methods of IR spectroscopy, spectrophotometry, thermogravimetry, pH metry, low-temperature adsorption-desorption of nitrogen, chemical and elemental analysis of the surface, the surface structure and its quantitative chemical composition, and also parameters of porous structure of initial and chemically modified aerosilogels were determined. Sorption of benzoic, salicylic and β-resorcylic acids on aerosilogels from aqueous buffer solutions with pH=1 was studied. The insignificant contribution of silanol and aminopropyl groups and complete participation of chemically fixed β-cyclodextrin in the sorption of aromatic acids were proved. The results obtained are analyzed using kinetic models for pseudo-first and pseudo-second order processes, as well as Langmuir and Freundlich models for equilibrium adsorption on homogeneous and heterogeneous surfaces. It has been found that the sorption kinetic processes are well described by a pseudo-first order equation (in the presence of one type of functional groups on the surface) and a pseudo-second order equation for bi- and trifunctional aerosilogels. Experimental results on the equilibrium sorption of aromatic acids on β-cyclodextrin-containing aerosilogel are in good agreement with the Langmuir adsorption equation. This is evidence of decisive contribution of grafted oligosaccharide groups to the sorption of organic acids. The proposed chemical approach to increasing the sorption activity of aerosilogel can be used to obtain specific chromatographic carriers, as well as inorganic sorbents for the effective removal of small amounts of highly toxic organic substances from water and aqueous solutions. [ABSTRACT FROM AUTHOR]

Gallic acid, protocatechuic acid, catechol, and pyrogallol are only a few examples of industrially relevant aromatics. Today much attention is paid to the development of new microbial factories for the environmentally friendly biosynthesis of industrially relevant chemicals with renewable resources or organic pollutants as the starting material. The non–conventional yeast, Blastobotrys raffinosifermentans , possesses attractive properties for industrial bio-production processes such as thermo- and osmotolerance. An additional advantage is its broad substrate spectrum, with tannins at the forefront. The present study is dedicated to the characterization of catechol-1,2-dioxygenase (Acdo1p) and the analysis of its function in B. raffinosifermentans tannic acid catabolism. Acdo1p is a dimeric protein with higher affinity for catechol (K M = 0.004 ± 0.001 mM, k cat = 15.6 ± 0.4 s–1) than to pyrogallol (K M = 0.1 ± 0.02 mM, k cat = 10.6 ± 0.4 s–1). It is an intradiol dioxygenase and its reaction product with catechol as the substrate is cis,cis -muconic acid. B. raffinosifermentans G1212/YIC102-AYNI1-ACDO1-6H, which expresses the ACDO1 gene under the control of the strong nitrate-inducible AYNI1 promoter, achieved a maximum catechol-1,2-dioxygenase activity of 280.6 U/L and 26.9 U/g of dry cell weight in yeast grown in minimal medium with nitrate as the nitrogen source and 1.5% glucose as the carbon source. In the same medium with glucose as the carbon source, catechol-1,2-dioxygenase activity was not detected for the control strain G1212/YIC102 with ACDO1 expression under the regulation of its respective endogenous promoter. Gene expression analysis showed that ACDO1 is induced by gallic acid and protocatechuic acid. In contrast to the wild-type strain, the B. raffinosifermentans strain with a deletion of the ACDO1 gene was unable to grow on medium supplemented with gallic acid or protocatechuic acid as the sole carbon source. In summary, we propose that due to its substrate specificity, its thermal stability, and its ability to undergo long-term storage without significant loss of activity, B. raffinosifermentans catechol-1,2-dioxygenase (Acdo1p) is a promising enzyme candidate for industrial applications. [ABSTRACT FROM AUTHOR]

Gallic acid, protocatechuic acid, catechol, and pyrogallol are only a few examples of industrially relevant aromatics. Today much attention is paid to the development of new microbial factories for the environmentally friendly biosynthesis of industrially relevant chemicals with renewable resources or organic pollutants as the starting material. The non–conventional yeast, Blastobotrys raffinosifermentans, possesses attractive properties for industrial bio-production processes such as thermo- and osmotolerance. An additional advantage is its broad substrate spectrum, with tannins at the forefront. The present study is dedicated to the characterization of catechol-1,2-dioxygenase (Acdo1p) and the analysis of its function in B. raffinosifermentans tannic acid catabolism. Acdo1p is a dimeric protein with higher affinity for catechol (KM = 0.004 ± 0.001 mM, kcat = 15.6 ± 0.4 s–1) than to pyrogallol (KM = 0.1 ± 0.02 mM, kcat = 10.6 ± 0.4 s–1). It is an intradiol dioxygenase and its reaction product with catechol as the substrate is cis,cis-muconic acid. B. raffinosifermentans G1212/YIC102-AYNI1-ACDO1-6H, which expresses the ACDO1 gene under the control of the strong nitrate-inducible AYNI1 promoter, achieved a maximum catechol-1,2-dioxygenase activity of 280.6 U/L and 26.9 U/g of dry cell weight in yeast grown in minimal medium with nitrate as the nitrogen source and 1.5% glucose as the carbon source. In the same medium with glucose as the carbon source, catechol-1,2-dioxygenase activity was not detected for the control strain G1212/YIC102 with ACDO1 expression under the regulation of its respective endogenous promoter. Gene expression analysis showed that ACDO1 is induced by gallic acid and protocatechuic acid. In contrast to the wild-type strain, the B. raffinosifermentans strain with a deletion of the ACDO1 gene was unable to grow on medium supplemented with gallic acid or protocatechuic acid as the sole carbon source. In summary, we propose that due to its substrate specificity, its thermal stability, and its ability to undergo long-term storage without significant loss of activity, B. raffinosifermentans catechol-1,2-dioxygenase (Acdo1p) is a promising enzyme candidate for industrial applications.

The potential of Pd/Pt complexes for catalytic carboxylation of arenes with CO2 is investigated by means of computational chemistry. Recently we reported that the bis[(2‐methoxyphenyl)phosphino]‐benzenesulfonamido palladium complex 1 inserts CO2 reversibly in its Pd−C(aryl) bond generating carboxylato complex 2. In the present work we study how geometric and electronic factors of various ligands and substrates influence the overall activation barrier (energy span, ES) of a potential catalytic cycle for arene carboxylation comprising this elementary step. The tendency of the key intermediates to dimerize and thus deactivating the potential catalysts is examined as well as the role of the base, which inevitably is needed to stabilize the reaction product. We show that Pd and Pt complexes I(Pd)‐L16‐S1 and I(Pt)‐L16‐S1 do not dimerize, enable the computation of complete catalytic cycles, and show interestingly low ES values of 26.8 and 24.5 kcal/mol, respectively. [ABSTRACT FROM AUTHOR]

Natural Products phytochemical provide a rich source for therapeutic discovery and has led to the development of many drugs. Thus, the aim of this study was to obtaining a metabolic profiling from ethanol extract of Inga semialata leaves (EEIS) selected by bioassay antimalarial and nematostatic and identify metabolites in mixture by co-injection experiments and NMR spectroscopy. The chemical composition of this species indicated a wide variety of aromatic acids (vanillic acid, 3,4,5-trimethoxy benzoic acid, gallic acid, methyl gallate, p-coumaric acid and ferulic acid), flavonoids (quercetin, myricetin-3-O-rhamnoside and myricetin-3-O-(2"-O-galloyl)-α-rhamnopyranoside), triterpenes (lupeol, α-amyrin, friedelin and oleanolic acid) and the 2-hydroxyethyl-dodecanoate. The antimalarial assay showed that the I. semialatan-hexane fraction presented higher inhibition percentage than the Chloroquine standard and may be considered a potential source of compounds with antimalarial activity while the EEIS and its fractions showed nematostatic potential below 17% in the assay of nematostatic evaluation against the parasite Meloidogyne incognita. [ABSTRACT FROM AUTHOR]

Six new aromatic acids (1–6) and three new leucine derivatives containing an unusual oxime moiety (7–9) were isolated and identified from the deep-sea-derived actinomycetes strain Streptomyces chumphonensis SCSIO15079, together with two known compounds (10–11). The structures of 1–9 including absolute configurations were determined by detailed NMR, MS, and experimental and calculated electronic circular dichroism spectroscopic analyses. Compounds 1–9 were evaluated for their antimicrobial and cytotoxicity activities, as well as their effects on intracellular lipid accumulation in HepG2 cells. Compounds 3 and 4, with the most potent inhibitory activity on intracellular lipid accumulation at 10 μM, were revealed with potential antihyperlipidemic effects, although the mechanism needs to be further studied. [ABSTRACT FROM AUTHOR]

Adaptive laboratory evolution (ALE) is a powerful approach for improving phenotypes of microbial hosts. Evolved strains typically contain numerous mutations that can be revealed by whole-genome sequencing. However, determining the contribution of specific mutations to new phenotypes is typically challenging and laborious. This task is complicated by factors such as the mutation type, the genomic context, and the interplay between different mutations. Here, a novel approach was developed to identify the significance of mutations in strains evolved from Acinetobacter baylyi ADP1. This method, termed rapid advantageous mutation screening and selection (RAMSES), was used to analyze mutants that emerged from stepwise adaptation to and consumption of high levels of ferulate, a common lignin-derived aromatic compound. After whole-genome sequence analysis, RAMSES allowed rapid determination of effective mutations and seamless introduction of the beneficial mutations into the chromosomes of new strains with different genetic backgrounds. This simple approach to reverse engineering exploits the natural competence and high recombination efficiency of ADP1. Mutated DNA, added directly to growing cells, replaces homologous chromosomal regions to generate transformants that will become enriched if there is a selective benefit. Thus, advantageous mutations can be rapidly identified. Here, the growth advantage of transformants under selective pressure revealed key mutations in genes related to aromatic transport, including hcaE, hcaK, and vanK, and a gene, ACIAD0482, which is associated with lipopolysaccharide synthesis. This study provided insights into the enhanced utilization of industrially relevant aromatic substrates and demonstrated the use of A. baylyi ADP1 as a convenient platform for strain development and evolution studies. [ABSTRACT FROM AUTHOR]

In this study a class of DESs based on triethylamine (TEA) and aromatic acids was synthesized and used in the extractive denitrogenation of model oil fraction firstly. The structures of DESs were characterized by nuclear magnetic resonance and Fourier transform infrared spectrometer. The factors that influence extraction efficiency and distribution coefficient were investigated. The extraction performance of TEA/o-hydroxybenzoic acid (OHBA) is better than that of TEA/benzoic acid and TEA/o-methylbenzoic acid. The extraction efficiencies of quinoline and indole reach up to 99.1 and 98.3% only through two extraction stages, respectively. The extraction efficiency is not sensitive to reaction temperature and initial nitrogen content. The DESs based on TEA and aromatic acids exhibit excellent regeneration performance. In summary, the DESs based on TEA and aromatic acids are excellent extracting agents for basic and non-basic nitrogen compounds and will become promising extracting agents for the oil fraction denitrogenation. [ABSTRACT FROM AUTHOR]

This study investigated the effect of forage type (grass or red clover) and harvesting time (primary growth or regrowth) of silage on energy and N utilisation by sheep fed at maintenance level. Specifically, the assumption of constant loss of energy of digestible organic matter from energy losses in urine and CH4 applied in evaluation of silage metabolisable energy (ME) was investigated. Urinary excretion of high-energy phenolic compounds related to solubilisation of lignin was assumed to affect urinary energy (UE) losses from sheep fed highly digestible grass silage (GS). A total of 25 primary growth and regrowth silages of timothy (Phleum pratense) and meadow fescue (Festuca pratensis) grass mixtures and red clover (Trifolium pratense) samples collected in digestibility trials with sheep, including faecal and urine samples, were used for energy and N determinations. Urinary concentration of monophenolic compounds and CH4 emissions in vitro were also analysed. Daily faecal N output, CH4 yield (MJ/kg DM intake), proportion of CH4 energy in digestible energy (DE) and proportion of UE in DE were greater (P ≤ 0.03) in sheep fed red clover silage (RCS) than GS. Furthermore, less (P = 0.01) energy was lost as UE of DE in sheep fed primary growth GS compared with the other treatments. The relationship between UE and silage N intake or urinary N output for both silage types (i.e. grass v. red clover) was strong, but the fit of the regressions was better for GS than RCS. The CH4/DE ratio decreased (P < 0.05) and the UE/DE ratio increased (P < 0.05) with increasing organic matter digestibility in RCS. These relationships were not significant (P < 0.05) for the GS diets. The regression coefficient was higher (P < 0.05) for GS than RCS when regressing ME concentration on digestible organic matter. The results of this study imply that ME/DE ratio is not constant across first-cut GS of different maturities. The ME production response may be smaller from highly digestible first-cut GS but could not be clearly related to urinary excretion of monophenols derived from solubilisation of lignin. Furthermore, energy lost in urine was not clearly defined for RCS and was much more predictable for GS from silage N concentration.

A series of new lappaconitine structural analogs were prepared via esterification of the lappaconine C-4 hydroxyl by aromatic acids. [ABSTRACT FROM AUTHOR]

Background. At present, qunoline derivatives occupy a special place among biologically active heterocyclic compounds widely used in medicine and agriculture. The drug "Chloroquine", one of the main drugs used in the treatment of COVID-19, contains a quinoline core at the base of the molecule. Modification of quinolone alkaloids, which are found in large quantities in plants of the Rutaceae, is one of the promising areas of modern scientific research. Purpose. Synthesis of amides of 6'-aminodubamine, obtained on the basis of the 2-arylquinoline alkaloid dubamine, with various aromatic acids. Methodology. Synthesis of amides based on 6'-aminodubamine was carried out by 2 methods. The structure of the synthesized compounds is proved by modern physical and chemical methods. Originality. The synthesis of 6'-aminodubamine amides with aromatic acids was carried out for the first time. Findings. The synthesis of 2-(4',5'-methylenedioxin-2'-(N-arylamido) was carried out with high yields(60.4-80.1%).)-phenyl)-quinolines, the structure of the synthesized substances was proved using IR, mass, 1H, and 13C NMR spectroscopic methods. [ABSTRACT FROM AUTHOR]

Pseudomonas putida KT2440 (hereafter KT2440) is a well-studied platform bacterium for the production of industrially valuable chemicals from heterogeneous mixtures of aromatic compounds obtained from lignin depolymerization. KT2440 can grow on lignin-related monomers, such as ferulate (FA), 4-coumarate (4CA), vanillate (VA), 4-hydroxybenzoate (4HBA), and protocatechuate (PCA). Genes associated with their catabolism are known, but knowledge about the uptake systems remains limited. In this work, we studied the KT2440 transporters of lignin-related monomers and their substrate selectivity. Based on the inhibition by protonophores, we focused on five genes encoding aromatic acid/H+ symporter family transporters categorized into major facilitator superfamily that uses the proton motive force. The mutants of PP_1376 (pcaK) and PP_3349 (hcnK) exhibited significantly reduced growth on PCA/4HBA and FA/4CA, respectively, while no change was observed on VA for any of the five gene mutants. At pH 9.0, the conversion of these compounds by hcnK mutant (FA/4CA) and vanK mutant (VA) was dramatically reduced, revealing that these transporters are crucial for the uptake of the anionic substrates at high pH. Uptake assays using 14C-labeled substrates in Escherichia coli and biosensor-based assays confirmed that PcaK, HcnK, and VanK have ability to take up PCA, FA/4CA, and VA/PCA, respectively. Additionally, analyses of the predicted protein structures suggest that the size and hydropathic properties of the substrate-binding sites of these transporters determine their substrate preferences. Overall, this study reveals that at physiological pH, PcaK and HcnK have a major role in the uptake of PCA/4HBA and FA/4CA, respectively, and VanK is a VA/PCA transporter. This information can contribute to the engineering of strains for the efficient conversion of lignin-related monomers to value-added chemicals. • Aromatic acid/H+ symporters from Pseudomonas putida KT2440 were identified and characterized. • PcaK, HcnK, and VanK mediate protocatechuate/4-hydroxybenzoate, ferulate/4-coumarate, and vanillate uptake, respectively. • Escherichia coli cells expressing the transporter genes display uptake for the corresponding substrate. • Size and hydropathic properties of the substrate-binding sites are suggested to determine transporter substrate preferences. • These transporters are useful targets for enhanced microbial production of valuable chemicals from lignin-related monomers. [ABSTRACT FROM AUTHOR]

Six new aromatic acids (1–6) and three new leucine derivatives containing an unusual oxime moiety (7–9) were isolated and identified from the deep-sea-derived actinomycetes strain Streptomyces chumphonensis SCSIO15079, together with two known compounds (10–11). The structures of 1–9 including absolute configurations were determined by detailed NMR, MS, and experimental and calculated electronic circular dichroism spectroscopic analyses. Compounds 1–9 were evaluated for their antimicrobial and cytotoxicity activities, as well as their effects on intracellular lipid accumulation in HepG2 cells. Compounds 3 and 4, with the most potent inhibitory activity on intracellular lipid accumulation at 10 μM, were revealed with potential antihyperlipidemic effects, although the mechanism needs to be further studied.

In this second research report (i.e., Part II), an ionic liquid (IL)-bonded silica column having an anion-exchange characteristic is described and characterized chromatographically with test acidic solute probes and by physical measurements such as Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). The IL anion-exchange stationary phase consists of a short alkyl chain IL stationary phase that has been synthesized by covalently immobilizing 1-ethylimidazole on a silica substrate through chloropropyltrimethoxysilane tether. The retention characteristics of the resulting stationary phase have been examined with acidic solutes such as aromatic acid derivatives and nucleotides. The test results show good resolution and separation efficiency indicating the presence of different interaction mechanisms such as π–π, electrostatic and hydrophobic interactions to a certain extent. Abbreviations: ABs: alkylbenzenes; ADP: adenosine 5′-diphosphate; AMP: adenosine 5′-monophosphate; CPTMS: 3-chloropropyltrimethoxysilane; ILs: ionic liquids; UMP: uridine 5′-monophosphate; UDP: uridine 5′-diphosphate; UTP: uridine 5′-triphosphate. [ABSTRACT FROM AUTHOR]

This study investigated the effect of forage type (grass or red clover) and harvesting time (primary growth or regrowth) of silage on energy and N utilisation by sheep fed at maintenance level. Specifically, the assumption of constant loss of energy of digestible organic matter from energy losses in urine and CH4 applied in evaluation of silage metabolisable energy (ME) was investigated. Urinary excretion of high-energy phenolic compounds related to solubilisation of lignin was assumed to affect urinary energy (UE) losses from sheep fed highly digestible grass silage (GS). A total of 25 primary growth and regrowth silages of timothy (Phleum pratense) and meadow fescue (Festuca pratensis) grass mixtures and red clover (Trifolium pratense) samples collected in digestibility trials with sheep, including faecal and urine samples, were used for energy and N determinations. Urinary concentration of monophenolic compounds and CH4 emissions in vitro were also analysed. Daily faecal N output, CH4 yield (MJ/kg DM intake), proportion of CH4 energy in digestible energy (DE) and proportion of UE in DE were greater (P ≤ 0.03) in sheep fed red clover silage (RCS) than GS. Furthermore, less (P = 0.01) energy was lost as UE of DE in sheep fed primary growth GS compared with the other treatments. The relationship between UE and silage N intake or urinary N output for both silage types (i.e. grass v. red clover) was strong, but the fit of the regressions was better for GS than RCS. The CH4/DE ratio decreased (P < 0.05) and the UE/DE ratio increased (P < 0.05) with increasing organic matter digestibility in RCS. These relationships were not significant (P < 0.05) for the GS diets. The regression coefficient was higher (P < 0.05) for GS than RCS when regressing ME concentration on digestible organic matter. The results of this study imply that ME/DE ratio is not constant across first-cut GS of different maturities. The ME production response may be smaller from highly digestible first-cut GS but could not be clearly related to urinary excretion of monophenols derived from solubilisation of lignin. Furthermore, energy lost in urine was not clearly defined for RCS and was much more predictable for GS from silage N concentration. [ABSTRACT FROM AUTHOR]

An in-situ approach is described for synthesis of poly(sulfobetaine-co-polyhedral oligomeric silsesquioxane) [poly(sulfobetaine-co-POSS)] that can be used in a hybrid monolithic column as a hydrophilic liquid chromatography (HILIC) stationary phase. Synthesis involves (a) radical polymerization of octa(propyl methacrylate)-polyhedral oligomeric silsesquioxane (MA-POSS) and organic monomers such as dimethylaminopropyl methacrylate or vinyl imidazole, and (b) in-situ ring-opening quaternization between 1,4-butane sultone and the organic monomers. The sulfobetaine groups are generated in-situ monolith. This obviates the need for synthesis of sulfobetaine monomer previously. The pore size and permeability of the material can be tuned by using a binary porogenic system (polyethyleneglycol 600 and acetonitrile) and via the composition of the polymerization mixture. The optimized hybrid monolith owns its merits to the presence of POSS and sulfobetaine groups with good mechanical stability, the lack of residual silanol groups, and adequate hydrophilicity. The column filled with the monoliths was evaluated as a stationary phase for HILIC. Several kinds of polar compounds (including nucleosides, bases, phenols, aromatic acids and amides) were separated by using mobile phases with high organic solvent fractions in capillary liquid chromatography. [ABSTRACT FROM AUTHOR]

Abstract Biomass burning (BB) is one of the largest sources of carbonaceous aerosols with adverse impacts on air quality, visibility, health and climate. BB emits a few specific aromatic acids (p -hydroxybenzoic, vanillic, syringic and dehydroabietic acids) which have been widely used as key indicators for source identification of BB-derived carbonaceous aerosols in various environmental matrices. In addition, measurement of p -hydroxybenzoic and vanillic acids in snow and ice cores have revealed the historical records of the fire emissions. Despite their uniqueness and importance as tracers, our current understanding of analytical methods, concentrations, diagnostic ratios and degradation processes are rather limited and scattered in literature. In this review paper, firstly we have summarized the most established methods and protocols for the measurement of these aromatic acids in aerosols and ice cores. Secondly, we have highlighted the geographical variability in the abundances of these acids, their diagnostic ratios and degradation processes in the environments. The review of the existing data indicates that the concentrations of aromatic acids in aerosols vary greatly with locations worldwide, typically more abundant in urban atmosphere where biomass fuels are commonly used for residential heating and/or cooking purposes. In contrast, their concentrations are lowest in the polar regions which are avoid of localized emissions and largely influenced by long-range transport. The diagnostic ratios among aromatic acids can be used as good indicators for the relative amounts and types of biomass (e.g. hardwood, softwood and herbaceous plants) as well as photochemical oxidation processes. Although studies suggest that the degradation processes of the aromatic acids may be controlled by light, pH and hygroscopicity, a more careful investigation, including closed chamber studies, is highly appreciated. Graphical abstract Schematic overview on the sources, transport, and deposition of biomass burning emissions. Image 1 Highlights • The analytical methods to quantify aromatic acids as BB tracer are summarized. • Abundances of the aromatic acids as BB tracer in different environments are discussed. • Degradation and hygroscopic properties have not been clarified up to now. • Perspectives involving measurement and field observation are recommended. Current research trends on aromatic acids as biomass burning tracers were comprehensively reviewed. [ABSTRACT FROM AUTHOR]

Twelve fungal strains were assayed to investigate their resistance to cinnamic and vanillic acids and their ability to remove these compounds from a liquid medium. In a first step, the effect of the two aromatic acids (1 g/L) on the fungal growth kinetic was studied. The results were modelled through a logistic like function (Dantigny equation) to estimate τ, which is the time to the half-maximum colony diameter. The key findings of this part were as follows: (i) generally, cinnamic acid exerted a stronger effect than vanillic acid; (ii) aromatic acids exerted a delay on the growth of some fungi and only one strain (Athelia rolfsii) was completely inhibited. In the second part, fungi were assayed to investigate their ability to remove cinnamic and vanillic acids (ca. 350 mg/kg) from liquid media at pH 3.5. The results indicated that the most efficient fungi were Aspergillus niger and Lasiodiplodia theobromae.

Abstract: A possibility of using a number of aromatic and heteroaromatic carboxylic acids and their halogen anhydrides as reactive matrix compounds for the analysis of alcohols of different structures by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry has been studied. It is shown that the acylation of alcohols with nicotinic and quinoline-6-carboxylic acid chlorides gives derivatives with high desorption/ionization efficiency under MALDI conditions, and that the free acids formed as a result of the hydrolysis of anhydrides act as matrix compounds. The proposed approach is tested on a number of aliphatic, alicyclic, and aromatic alcohols. [ABSTRACT FROM AUTHOR]

Issues of application of “green chemistry” principles to the extraction and separation of components of liquid mixtures have been discussed. In particular, quantitative characteristics of the interphase distribution of a number of aromatic acids in extraction systems based on polyethylene glycol and sodium sulfate have been determined. It has been shown that these systems, which do not contain components that are toxic or pose a fire hazard, are promising for the effective extraction of aromatic acids from natural and technogenic products. [ABSTRACT FROM AUTHOR]

Biomass burning is a serious problem in the environment and climate system. However, the source identification of biomass-burning aerosols was somewhat impeded, partly due to the difficulty in quantification of relevant molecular markers. In this study, we present reference values for five aromatic acids (including p -hydroxybenzoic, vanillic, dehydroabietic, syringic and p -coumaric acids) in the NIST Standard Reference Material (SRM) 1649b. The concentration of levoglucosan was also revisited. Notable positive matrix effect was found for vanillic, dehydroabietic, syringic and coumaric acid. Using the standard addition method, the average value of p -hydroxybenzoic, vanillic, syringic, dehydroabietic and p -coumaric acids in SRM 1649b were found to be 26.9, 9.53, 1.13, 7.60 and 1.66 μg g −1 , respectively. The analytical method developed in this study was also applied to the PM 10 samples from Beijing and PM 2.5 samples from South Asia (Godavari, Nepal). The ratios of vanillic to p -hydroxybenzoic acid and syringic to vanillic acid further suggested that their biomass-burning types are mainly related to hard wood and herbaceous species (i.e., agricultural residues). [ABSTRACT FROM AUTHOR]

Abstract: A palladium‐catalyzed tandem process of simple aromatic acids has been achieved to afford meta‐substituted biaryls in moderate to good yields. The reaction proceeds via carboxyl‐directed intermolecular cross‐dehydrogenative coupling and subsequent decarboxylation. The new C−C bonds in this transformation are formed in the ortho position of carboxyl and the reaction tolerates electron‐rich acids. Both symmetrical and unsymmetrical meta‐substituted biaryls can be directly synthesized via this method. [ABSTRACT FROM AUTHOR]

Tannins and hydroxylated aromatic acids, such as gallic acid (3,4,5-trihydroxybenzoic acid), are plant secondary metabolites which protect plants against herbivores and plant-associated microorganisms. Some microbes, such as the yeast Arxula adeninivorans are resistant to these antimicrobial substances and are able to use tannins and gallic acid as carbon sources. In this study, the Arxula gallic acid decarboxylase (Agdc1p) which degrades gallic acid to pyrogallol was characterized and its function in tannin catabolism analyzed. The enzyme has a higher affinity for gallic acid (Km −0.7 ± 0.2 mM, kcat −42.0 ± 8.2 s−1) than to protocatechuic acid (3,4-dihydroxybenzoic acid) (Km −3.2 ± 0.2 mM, kcat −44.0 ± 3.2 s−1). Other hydroxylated aromatic acids, such as 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid and 2,5-dihydroxybenzoic acid are not gallic acid decarboxylase substrates. A. adeninivorans G1212/YRC102-AYNI1-AGDC1, which expresses the AGDC1 gene under the control of the strong nitrate inducible AYNI1 promoter achieved a maximum gallic acid decarboxylase activity of 1064.4 U/l and 97.5 U/g of dry cell weight in yeast grown in minimal medium with nitrate as nitrogen source and glucose as carbon source. In the same medium, gallic acid decarboxylase activity was not detected for the control strain G1212/YRC102 with AGDC1 expression under the control of the endogenous promoter. Gene expression analysis showed that AGDC1 is induced by gallic acid and protocatechuic acid. In contrast to G1212/YRC102-AYNI1-AGDC1 and G1212/YRC102, A. adeninivorans G1234 [Δagdc1] is not able to grow on medium with gallic acid as carbon source but can grow in presence of protocatechuic acid. This confirms that Agdc1p plays an essential role in the tannic acid catabolism and could be useful in the production of catechol and cis,cis-muconic acid. However, the protocatechuic acid catabolism via Agdc1p to catechol seems to be not the only degradation pathway.

Combination treatments of surfactants and phenolic or short-chain organic acids (SCOA) may act synergistically or additively as sanitizers to inactive foodborne viruses and prevent outbreaks. The purpose of this study was to investigate the effect of gallic acid (GA), tannic acid, p-coumaric acid, lactic acid (LA), or acetic acid (AA), in combination with sodium dodecyl sulfate (SDS), against Tulane virus (TV), a surrogate for human norovirus. An aqueous stock solution of phenolic acids or SCOA with or without SDS was prepared and diluted in a twofold dilution series to 23the desired concentration with cell growth media (M119 plus 10% fetal bovine serum). The solution was inoculated with an equal proportion of 6 log PFU/mL TV with a treatment time of 5 min. The survival of TV was quantified using a plaque assay with LLC-MK2 cells. The minimum virucidal concentration was 0.5:0.7% (v/v) for LA-SDS at pH 3.5 (4.5-PFU/mL reduction) and 0.5:0.7% (v/v) AA-SDS at pH 4.0 (2.6-log PFU/mL reduction). GA and SDS demonstrated a minimum virucidal concentration of 12.5 mM GA-SDS at pH 7.0 (0.2:0.3% GA-SDS) with an 0.8-log PFU/mL reduction and 50 mM GA-SDS (0.8:1.4% GA-SDS at pH 7.0) increased log reduction to 1.6 log PFU/mL. The combination treatments of AA or LA with SDS at pH 7.0 did not produce significant log reduction, nor did individual treatments of tannic acid, GA, p-coumaric acid, AA, LA, or SDS. This study demonstrates that a surfactant, such as SDS, aids in the phenolic acid and SCOA toxicities against viruses. However, inactivation of TV by combination treatments is contingent upon the pH of the sanitizing solution being lower than the pKa value of the organic acid being used. This information can be used to develop sanitizing washes to disinfect food contact surfaces, thereby aiding in the prevention of foodborne outbreaks. [ABSTRACT FROM AUTHOR]

In galactoceramides, presence of fatty-acyl group on amide moiety or phytosphingosine group is some of the important features that influence the cytotoxicity. Continuous efforts are in progress to modify the fatty-acid moiety and phytosphingosine group present on the galactoceramides to enhance the cytotoxic potential of these compounds. Hence, in the present study, threonine-based β-galactoceramide and its derivatives were prepared by modifying the fatty-acyl group on amide moiety with different fatty-acyl moieties and aromatic acids employing trichloroacetimidate methodology. The structurally related threonine-based ceramide part was synthesized in multi-step process using different reagents. The ceramide part was glycosylated with galactose using trichloroacetimidate as donor. Further, all the synthesized compounds were evaluated for in vitro cytotoxicity against three cancer cell lines and one normal cell line and all the compounds exhibited good to moderate cytotoxicity against all the tested cancer cell lines. In aromatic derivatives, the compound 8i exhibited promising activity against MCF7, A549 and HeLa cancer cell lines with IC values of 14.08, 14.78, and 16.70 µM, respectively. In fatty-acid derivatives, two compounds exhibited promising activity, i.e., compound 8m against HeLa with IC value 16.34 µM and compound 8n against MCF7 with IC value 18.05 µM. Based on structure-activity relationship, aromatic acid derivatives exhibited potential activity as compared to fatty-acid derivatives. Further, the influence of some of the key factors such as spacer chain length between aromatic residue and amide functional group, methoxy substituents on aryl group, terminal unsaturation of fatty acid and branching chain effect on the cytotoxicity are discussed. Graphical abstract: [ABSTRACT FROM AUTHOR]

The main object of this work was to compare the corrosion powers of acidic species: naphthenic acid, fatty acid and aromatic acid which were found in petroleum fraction. They were blended into base oils to formulate three simulate oils (E, F and G) with the same TAN values of 2.3 mg KOH/g. AISI 316 steel surfaces immersed in oils were measured by Raman spectroscopy, energydispersive spectrum and scanning electron microscopy after 24, 48, 72 h to evaluate their corrosion. From the Raman images, the corrosion products were confirmed. Besides goethite (α-Fe(OOH)) in corrosion product E at 48 hours; magnetite (Fe3O4) in F at 24 hours; and hematite (α-Fe2O3and α-Fe2O3) in G at 72hours, there were disordered carbons on steel E and ferric benzoate film on steel G. The contents of elements from EDS have markedly different characteristics, indicating that dominant corrosion products on steel samples resulted from three acidic species are different. The morphology in SEM also corroborated above data that corrosion products have difference. Combining the data of three measurements, the rank of corrosion power based on the formations of ferric oxides was determined: fatty acid > naphthenic acid > aromatic acid. [ABSTRACT FROM AUTHOR]

A novel magnetic adsorbent was designed and synthesized for adsorption and determination of hazardous aromatic acids (AAs) based on the zeolite imidazolate frameworks of Eu (ZIF-Eu), Fe 3 O 4 and carboxyl multi-walled carbon nanotubes (MWCNTs-COOH). ZIF-Eu was fabricated for the first time, and Fe 3 O 4 nanoparticles were encapsulated in MWCNTs-COOH, which made the separation procedure simple and easy-realizable. Adsorption experiments indicated that the adsorbent had superior affinity and selectivity to adsorbates with multi-ring, multi-carboxylic and electron-withdrawing group substituted structures, and it can achieve the selective adsorption of AAs from the aromatic mixture, the mechanism of which was evaluated and attributed to the intermolecular π-π electron-donor-acceptor (EDA) and hydrogen-bonding interactions. Seven AAs with different substituents were selected as target adsorbates to investigate the influences of critical experimental conditions on the adsorption efficiencies. Adsorption isotherms and kinetics were investigated and indicated that Dubinin-Ashtakhov model and pseudo-second-order model could well describe the adsorption of AAs on the nanocomposite. Adsorption thermodynamics study suggested that the adsorption reactions were spontaneous, endothermic and thermodynamically favorable. In addition, desorption conditions for AAs, and reusability of the novel adsorbent was evaluated, which confirmed the recyclability of the novel adsorbent. [ABSTRACT FROM AUTHOR]

The consequences of microbial activity in petroleum reservoirs, such as deterioration in crude oil quality and technical problems in oil production were recognized a long time ago, while the metabolic capability and hydrocarbon transformation processes of microorganisms are less understood. In this study, petroleum hydrocarbons serving as substrates for microorganisms, as well as the organic acid composition of formation water were investigated for samples originating from an oilfield in Upper Austria with an elevated reservoir temperature around 78 °C. Many alkanoic, aromatic and dicarboxylic acids were found in the formation water, and which may derive from microbial degradation of hydrocarbons. To the best of our knowledge, polyalkylated succinic acids such as 2,2- and 2,3-dimethylsuccinic acid, 2-ethyl-3-methylsuccinic acid and 2,2,3-trimethylsuccinic acid have not been described in formation water before. Considering the degree of substitution, we conclude that many of the alkylated succinic acids did not derive from the direct activation of hydrocarbons via addition to fumarate. It is more likely that they were produced during the course of hydrocarbon transformation and intracellular catabolism of fatty acids, and possibly other compounds, and play a role in protection mechanisms against high temperature and solvent stress. The results provide clear evidence for ongoing biodegradation of hydrocarbons in a petroleum reservoir at elevated temperature close to the generally accepted threshold of 80 °C. [ABSTRACT FROM AUTHOR]

A metal-free highly efficient synthesis of a wide range of 4-propenyl 1,4-DHPs from pyridines, methyl propiolate, and aromatic acids is described. The reactions are conducted under convenient conditions and provide products with excellent regioselectivity in good to excellent yields, with broad substrate scope. [ABSTRACT FROM AUTHOR]

Among the key environmental factors influencing the fate and transport of radionuclides in the environment is natural organic matter (NOM). While this has been known for decades, there still remains great uncertainty in predicting NOM-radionuclide interactions because of lack of understanding of radionuclide interactions with the specific organic moieties within NOM. Furthermore, radionuclide-NOM studies conducted using modelled organic compounds or elevated radionuclide concentrations provide compromised information related to true environmental conditions. Thus, sensitive techniques are required not only for the detection of radionuclides, and their different species, at ambient and/or far-field concentrations, but also for potential trace organic compounds that are chemically binding these radionuclides. GC-MS and AMS techniques developed in our lab are reviewed here that aim to assess how two radionuclides, iodine and plutonium, form strong bonds with NOM by entirely different mechanisms; iodine tends to bind to aromatic functionalities, whereas plutonium binds to N-containing hydroxamate siderophores at ambient concentrations. While low-level measurements are a prerequisite for assessing iodine and plutonium migration at nuclear waste sites and as environmental tracers, it is necessary to determine their in-situ speciation, which ultimately controls their mobility and transport in natural environments. More importantly, advanced molecular-level instrumentation (e.g., nuclear magnetic resonance (NMR) and Fourier-transform ion cyclotron resonance coupled with electrospray ionization (ESI-FTICRMS) were applied to resolve either directly or indirectly the molecular environments in which the radionuclides are associated with the NOM. [ABSTRACT FROM AUTHOR]

An improved synthesis of 1-O-acyl glucosyl esters that avoids the use of expensive Ag reagents as well as the hydrolysis of unstable glucosyl bromides is reported. Notably, βconfiguration products were obtained exclusively in good yields. [ABSTRACT FROM AUTHOR]

Distribution ratios of acidic, neutral, and basic compounds were determined in polyethylene glycol (PEG)-6000/Dextran-75000 aqueous biphasic systems (ABSs) at incremental pH values. The nature of the solute species present at each pH was identified using speciation diagrams, and it was determined that the distribution ratios were related to their charge, with maximum distribution to the upper PEG-rich phase when the neutral species were dominant. The results suggest that this ABS is tunable with simple modifications of pH leading to increasing selectivity for specific target solutes. [ABSTRACT FROM AUTHOR]

Qualitative lignin analysis relies rather much on studies of lignin degradation products. As concerns precise quantification of lignin’s composition such studies in general have obvious limitations. Aromatic acids obtained on permanganate oxidation of pretreated lignins (cleavage of ethers and alkylation of phenolic groups) offer a possibility to estimate the amounts of differently substituted aromatic units in lignins. An equation is derived for the calculation of the gross composition of lignins based on the yields of methoxy-substituted aromatic acids obtained on permanganate oxidation of lignins with methylated phenolic groups. The equation could also be used for the calculation of the phenolic content in a lignin sample based on permanganate oxidation data, provided that such data are available for a similar lignin sample with known phenolic content. Literature data for milled wood lignin from spruce are used to exemplify the calculations.

Molecular interactions between benzoic, salicylic, and acetylsalicylic acids and water contained within montmorillonite clay interlayer spaces are characterized by using variable temperature diffuse reflection infrared Fourier transform spectroscopy (VT-DRIFTS). By using sample perturbation and difference spectroscopy, infrared (IR) spectral variations resulting from the removal of interlayer water are used to characterize aromatic acid local environment changes. Difference spectra features representing functional group perturbations are correlated with changes in IR absorptions associated with -O-H and -C = O stretching vibrations. Results suggest that adsorbate carboxylic acid functionalities participate in extensive hydrogen bonding and that the strengths of these interactions are diminished when clays are dehydrated. The nature of these interactions and their temperature-dependent properties are found to depend on adsorbate structure and concentration as well as the clay interlayer cation. [ABSTRACT FROM AUTHOR]

In this paper, we report an efficient method by high-speed counter-current chromatography for the first separation of four aromatic acids and two analogs with similar structures and polarities from Clematis akebioides. First, the ethyl acetate extract was treated by silica gel column chromatography to enrich the target compounds. And then the fraction with target compounds were purified by high-speed counter-counter chromatography using a two-phase solvent system consisting of chloroform/acetonitrile/water (10:6:4, v/v). The results showed high-speed counter-current chromatography could be a powerful technology for the separation of compounds with similar structures and polarities. Besides, it was found acetonitrile could be a good methanol substitute when a chloroform/methanol/water system could not provide a good separation factor. This study provides a reference for the separation of compounds from Clematis akebioides. [ABSTRACT FROM AUTHOR]

Mass loss and m/z 18 mass spectrometric ion signal temperature profiles are used to characterize interactions between benzoic acid, salicylic acid, and acetylsalicylic acid adsorbates and potassium, sodium, and calcium montmorillonites. Temperature-dependent water desorption trends show that all three adsorbates cause significant disruptions to clay interlayer water molecule environments. Results suggest that the source of this disruption is the formation of adsorbate-water molecule-cation bridging through the adsorbate acid functionality. Salicylic and acetylsalicylic acids perturb interlayer water molecule environments more than benzoic acid. This is most likely due to the additional hydrogen bond-forming capabilities afforded by the hydroxyl (salicylic acid) and ester (acetylsalicylic acid) groups attached to the aromatic rings of these adsorbates. [ABSTRACT FROM AUTHOR]