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This article discusses the electrocatalytic synthesis of 1,2-dioxolanes from tetrasubstituted donor-acceptor cyclopropanes. The use of electrochemical activation allows for an alternative cleavage mode of C(sp3)-C(sp3) bonds, resulting in the formation of 1,2-dioxolanes. The study explores the optimization and reaction scope of this system, demonstrating the synthesis of 3,3,5,5-tetrasubstituted dioxolanes from various cyclopropanes. The proposed mechanism for this reaction is supported by previous studies on the electrochemical activation of donor-acceptor cyclopropanes. [Extracted from the article]

A methodology for the asymmetric peroxidation of γ,δ-unsaturated β-keto esters is presented. Using a cinchona-derived organocatalyst, the target δ-peroxy-β-keto esters were obtained in high enantiomeric ratios of up to 95:5. Additionally, these δ-peroxy esters can be readily reduced to chiral δ-hydroxy-β-keto esters without impacting the β-keto ester functionality. Importantly, this chemistry opens up a concise route to chiral 1,2-dioxolanes, a common motif in many bioactive natural products, via a novel P2O5-mediated cyclisation of the corresponding δ-peroxy-β-hydroxy esters. [ABSTRACT FROM AUTHOR]

The reaction of halogen-substituted benzaldehydes with 3-(1-chloroethoxy)prop-1-yne leads to the formation of unsaturated ethers derived from 2-hydroxyoxirane. The formation of the latter was confirmed by its reaction with acetone in the presence of BF3·Et2O to give substituted 1,3-dioxolanes. [ABSTRACT FROM AUTHOR]

Pesticide use cannot be completely abandoned in modern agriculture. Among agrochemicals, glyphosate is one of the most popular and, at the same time, most divisive herbicide. Since the chemicalization of agriculture is detrimental, various attempts are being made to reduce it. Adjuvants—substances that increase the efficiency of foliar application—can be used to reduce the amount of herbicides used. We propose low-molecular-weight dioxolanes as adjuvants for herbicides. These compounds quickly convert to carbon dioxide and water and do not harm plants. The aim of this study was to evaluate the efficacy of RoundUp® 360 Plus supported by three potential adjuvants: 2,2-dimethyl-1,3-dioxolane (DMD), 2,2,4-trimethyl-1,3-dioxolane (TMD), and (2,2-dimethyl-1,3-dioxan-4-yl)methanol (DDM), on a common weed species Chenopodium album L., under greenhouse conditions. Chlorophyll a fluorescence parameters and analysis of the polyphasic fluorescence (OJIP) curve, which examines changes in the photochemical efficiency of photosystem II, were used to measure plant sensitivity to glyphosate stress and verified the efficacy achieved by tested formulations. The effective dose (ED) values obtained showed that the weed tested was sensitive to reduced doses of glyphosate, with 720 mg/L needed to achieve 100% effectiveness. Compared to the glyphosate assisted with DMD, TMD, and DDM, ED was reduced by 40%, 50%, and 40%, respectively. The application of all dioxolanes at a concentration equal to 1 vol.% significantly enhanced the herbicide's effect. Our study showed that for C. album there was a correlation between the change in OJIP curve kinetics and the applied dose of glyphosate. By analyzing the discrepancies in the curves, it is possible to show the effect of different herbicide formulations with or without dioxolanes at an early stage of its action, thus minimizing the time for testing new substances as adjuvants. [ABSTRACT FROM AUTHOR]

Most combinations of chemo‐ and biocatalysis take place in aqueous media or require a solvent change with complex intermediate processing. Using enzymes in the same organic solvent as the chemocatalyst eliminates this need. Here, it was shown that a complete chemoenzymatic cascade to form dioxolanes could be carried out in a purely organic environment. The result, including downstream processing, was compared with a classical mode, shifting solvent. First, a two‐step enzyme cascade starting from aliphatic aldehydes to chiral diols (3,4‐hexanediol and 4,5‐octanediol) was run either in an aqueous buffer or in the potentially biobased solvent cyclopentyl methyl ether. Subsequently, a ruthenium molecular catalyst enabled the conversion to dioxolanes [e. g. (4S,5S)‐dipropyl‐1,3‐dioxolane]. Importantly, the total synthesis of this product was not only highly stereoselective but also based on the combination of biomass, CO2, and hydrogen, thus providing an important example of a bio‐hybrid chemical. [ABSTRACT FROM AUTHOR]

By free radical addition of ethanedithiol to alkyl- and cycloalkyl-substituted methylene dioxolanes, the bis-adducts tested then as a plasticizer for PVC have been obtained. It has been established as a result of the carried out investigations that the introduction of the synthesized compounds into PVC composition improves the physical-mechanical properties, which has been connected with the availability of sulfur atoms, carbonyl groups and ether bond in the molecules of bis-adducts. The high operational indices from PVCplastics indicate good plasticizing properties of the synthesized bis-adducts, and therefore they can be recommended for practical use. [ABSTRACT FROM AUTHOR]

• Treatability was explored for 10 unregulated odorants (dioxanes and dioxolanes). • PAC adsorption outperformed chlorination and permanganate oxidation. • Molecular flexibility enhanced site accessibility and thus odorant adsorption. • High structural flexibility reduced odorant susceptibility to NOM competition. • Pre-oxidation exacerbated NOM competition and impaired odorant adsorption. Odorous dioxanes and dioxolanes, a class of cyclic acetals often produced as byproducts in polyester resin manufacturing, are problematic in drinking water treatment due to their low odor thresholds and resistance to conventional treatment technology. Our research focuses on the removal of ten dioxane/dioxolane compounds through oxidation and adsorption processes, exploring the key molecular properties that govern the treatmentability. We discovered that both chlorination and permanganate oxidation were largely ineffective at degrading cyclic acetals, achieving less than 20% removal even at high applicable doses. Conversely, powdered activated carbon (PAC) adsorption proved to be a more effective method, with a removal of > 90% at a PAC dosage of 10 mg/L for seven out of ten compounds. The presence of natural organic matter (NOM) reduced PAC adsorbability for all odorants, but the deterioration level substantially varied and mostly affected by structural flexibility as indicated by the number of rotatable bonds. The results of both the experimental investigation and molecular simulation corroborated the hypothesis that more rotatable bonds (from one to three here) are indicative of greater structural flexibility, which in consequence determines the susceptibility of cyclic acetals to NOM competitive adsorption. Increased structural flexibility could facilitate greater entry into silt-like micropores or achieve preferential adsorption sites with more compatible morphology against NOM competition. When pre-oxidation (chlorination and permanganate oxidation) and adsorption were applied sequentially, additional low molecular weight NOM components produced by pre-oxidation resulted in intensified NOM competition and decreased odorant adsorbability. If this combination is inevitably required for algae and odorant control, it would be beneficial to utilize a wise screen for oxidants and a reduced oxidant dose (less than 2 mg/L) to mitigate the deterioration of odorant adsorption. This study elucidates the roles of structural flexibility in influencing the treatability of dioxanes and dioxolanes, extending beyond the solely well-established effects of hydrophobicity. It also presents rational practice guidelines for the combination of pre-oxidation and adsorption in addressing odor incidents associated with dioxane and dioxolane compounds. [Display omitted] [ABSTRACT FROM AUTHOR]

Cucumber Corynespora leaf spot caused by Corynespora cassiicola is the primary disease responsible for reducing cucumber yield, and prochloraz is the main fungicide used to control C. cassiicola. This study investigated the sensitivity and resistance mechanism of C. cassiicola isolates to prochloraz, and found that C. cassiicola has developed resistance to prochloraz. The prochloraz EC 50 values ranged from 0.02 to 2.33 μg/mL, with a mean of 0.436 ± 0.447 μg/mL. In total, 36 of 146 isolates exhibited prochloraz resistance. The resistant isolates had no fitness cost and could not be completely controlled by 50 μg/mL prochloraz on detached leaves. Prochloraz exhibited positive cross-resistance with propiconazole and tebuconazole but not with difenoconazole, carbendazim, trifloxystrobin and pydiflumetofen. The sensitive isolates had significantly lower ergosterol content than the resistant isolates after prochloraz treatment. Compared to sensitive isolates, prochloraz-resistant isolates had no CcCYP51 gene mutation, but the CcCYP51A and CcCYP51B gene expression levels were significantly higher under the treatment of prochloraz. The overexpression of CcCYP51A and CcCYP51B were associated with prochloraz resistance in C. cassiicola., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Background: Since the onset of the coronavirus disease 2019 (COVID-19) pandemic, remarkable advances have been made in vaccine development to reduce mortality. However, therapeutic interventions for COVID-19 are comparatively limited despite these intensive efforts. Furthermore, the rapid mutation capability of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a characteristic of its RNA structure, has led to the emergence of multiple variants, necessitating a shift from a predominantly vaccine-centric approach to one that encompasses therapeutic strategies. 6'-Hydroxy justicidin B (6'-HJB), an arylnaphthalene lignan isolated from Justicia procumbens, a traditional Chinese medicine, is known for its antiviral properties., Hypothesis/purpose: The aim of the present study was to assess the effectiveness and safety of 6'-HJB against SARS-CoV-2 in order to determine its potential as a therapeutic agent against COVID-19., Methods: The efficacy of 6'-HJB was evaluated both in vitro using Vero and Calu-3 cell lines and in vivo using ferrets. The safety assessment included toxicokinetics, safety pharmacology, and Good Laboratory Practice (GLP)-compliant toxicity evaluations following single- and repeated-dose toxicity studies in dogs., Results: The anti-SARS-CoV-2 efficacy of 6'-HJB was evaluated through dose-response curve (DRC) analysis using immunofluorescence; 6'-HJB demonstrated superior inhibition of SARS-CoV-2 growth and lower cytotoxicity than remdesivir. In SARS-CoV-2-infected ferret, 6'-HJB showed efficacy comparable to that of the positive control, Truvada. Further GLP toxicity studies corroborated the safety profile of 6'-HJB. Single-dose and 4-week repeated oral toxicity studies in Beagle dogs demonstrated minimal harmful effects at the highest dosages. The lethal dose of 6'-HJB exceeded 2,000 mg kg -1 in Beagle dogs. Toxicokinetic and GLP safety pharmacology studies demonstrated no adverse effects of 6'-HJB on metabolic processes, respiratory or central nervous systems, or cardiac functions., Conclusion: This research highlights both the antiviral efficacy and safety profile of 6'-HJB, underscoring its potential as a novel COVID-19 treatment option. The potential of 6'-HJB was demonstrated using modern scientific methodologies and standards., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Bumblebees and other key pollinators are experiencing global declines, a phenomenon driven by multiple environmental stressors, including pesticide exposure. While bumblebee queens spend most of their life hibernating underground, no study to date has examined how exposure to pesticide-contaminated soils might affect bumblebee queens during this solitary phase of their lifecycle. We exposed Bombus impatiens queens (n = 303) to soil treated with field-realistic concentrations of two diamide insecticides (chlorantraniliprole and cyantraniliprole) and two fungicides (boscalid and difenoconazole), alone or combined, during a 30-week hibernation period. We found that exposure to boscalid residues in soil doubled the likelihood of queens surviving through the colony initiation period (after successful hibernation) and laying eggs. Our data also revealed complex interactions between pesticide exposure and queen body mass on aspects of colony founding. Among others, exposure to cyantraniliprole led to lethal and sublethal post-hibernation effects that were dependent on queen size, with larger queens showing higher mortality rates, delayed emergence of their first brood, and producing smaller workers. Our results show that effects of pesticide exposure depend on intrinsic traits of bumblebee queen physiology and challenge our understanding of how bees respond to pesticides under environmentally realistic exposure scenarios., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

A kinetic and mechanistical studies of the new pathway for competitive transformation of ethylene glycol by alumina and silica gel have been described. Commercial alumina (Al com), synthetic alumina (Al syn), commercial silica gel (Si com) and synthetic silica gel (Si syn) were used for the transformation of ethylene glycol to a mixture of diethylene glycol, 1,4-dioxane and 2-methyl-1,3-dioxolane via acetaldehyde by heating at 150 °C under autogenous pressure without solvent. The results show that the yield of these three products strongly depends on the nature of the used catalyst and the reaction time.

Computed descriptors for acyclic diaminocarbene ligands are developed in the context of a gold catalyzed enantioselective tandem [3,3]-sigmatropic rearrangement-[2+2]-cyclization. Surrogate structures enable the rapid identification of parameters that reveal mechanistic characteristics. The observed selectivity trends are validated in a robust multivariate analysis facilitating the development of a highly enantioselective process.

A methodology for the asymmetric peroxidation of γ,δ-unsaturated β-keto esters is presented. Using a cinchona-derived organocatalyst, the target δ-peroxy-β-keto esters were obtained in high enantiomeric ratios of up to 95:5. Additionally, these δ-peroxy esters can be readily reduced to chiral δ-hydroxy-β-keto esters without impacting the β-keto ester functionality. Importantly, this chemistry opens up a concise route to chiral 1,2-dioxolanes, a common motif in many bioactive natural products, via a novel P2O5-mediated cyclisation of the corresponding δ-peroxy-β-hydroxy esters.

[Display omitted] • Contribution of ozone and •OH to dioxolanes removal during ozonation was evaluated. • Reaction rate constants of dioxolanes with ozone and •OH were determined. • A kinetic model well simulated the observed ozonation of dioxolanes under various conditions. • Transformation pathways and potential environment risks of 1,3-D and 2-M-1,3-D during ozonation were analyzed. Dioxolanes, which are structural analogs to dioxane, are emerging persistent mobile organic contaminants. These compounds are frequently detected in water and wastewater, but their removal has been rarely addressed in the literature. This work systematically investigated the ozonation of two representative dioxolanes, i.e., 1,3-dioxolane (1,3-D) and 2-methyl-1,3-dioxolane (2-M-1,3-D). The degradation rates of two dioxolanes exhibited a positive correlation with both ozone dosage and solution pH increment. Specifically, direct ozone oxidation dominates the degradation of dioxolanes at slightly acidic pH, while hydroxyl radical (•OH) becomes the primary oxidant under weak alkaline condition. The second-order reaction rate constants of ozone with 1,3-D and 2-M-1,3-D were determined to be 5.48 and 8.00 M−1s−1, respectively. The reaction rate constants with •OH were 9 orders of magnitude higher, reaching (3.75-8.18) × 109 and (2.65-5.78) × 109 M−1s−1 for 1,3-D and 2-M-1,3-D, respectively. A kinetic model involving 112 reactions well simulated the degradation of 1,3-D and 2-M-1,3-D under various conditions accordingly. Eight transformation products were identified totally, and seven of them (i.e., formic acid, acetic acid, oxalic acid, formaldehyde, acetaldehyde, glyoxylic acid, and 1,2-ethanediol monoacetate) were quantified. The observed evolution of these identified degradation products concludes that the degradation of 1,3-D and 2-M-1,3-D during ozonation mainly involves H-abstraction, dimerization, ring opening, disproportionation, and hydrolysis. This work not only provides essential kinetic data of dioxolanes, but also sheds light on their potential transformation mechanisms and aquatic environment risks during ozonation process. [ABSTRACT FROM AUTHOR]

Modern agriculture relies heavily on pesticide use to meet the demands of food quality and quantity. Therefore, pesticides are often applied in mixtures, leading to a diverse cocktail of chemicals and their metabolites in soils, which can affect non-target organisms such as soil microorganisms. Pesticides are tested for their single effects, but studies on their interactive effects are scarce. This study aimed to determine the effects of up to three simultaneously applied pesticides on the soil microbial community and on their special function in pesticide degradation. Agricultural soil without previous pesticide application was exposed to different mixtures of the herbicide glyphosate (GLP), the phenoxy herbicide MCPA (2-methyl-4-chlorophenoxyacetic acid) and the fungicide difenoconazole (DFC) for up to 56 days. Isotopic and molecular methods were used to investigate effects of the mixtures on the microbial community and to follow the mineralization and utilization of GLP. An initial increase in the metabolic quotient by up to 35 % in the presence of MCPA indicated a stress reaction of the microbial community. The presence of multiple pesticides reduced both gram positive bacterial fatty acid methyl esters (FAMEs) by 13 % and the abundance of microorganisms with the genetic potential for GLP degradation via the AMPA (aminomethylphosphonic acid) pathway. Both the number of pesticides and the identities of individual pesticides played major roles. Surprisingly, an increase in 13 C-labelled GLP mineralization of up to 40 % was observed while carbon use efficiency (CUE) decreased. Interactions between multiple pesticides might alter the behavior of individual pesticides and be reflected in the microbial community. Our results highlight the importance of investigating not only single pesticides, but also pesticide mixtures and their interactions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Ringselective and regioselective acetonide protection of four diastereomeric triol systems (ribo & xylo with 1,3-syn configuration and arabino & lyxo with 1,3-anti configuration) were studied and certain useful generalizations are drawn as follows. Three triol systems i.e. xylo, arabino and lyxo triol systems have preferred only five membered acetonides (dioxolanes) over six membered acetonides (dioxanes). Selective formation of five membered anti acetonides was noticed when there is a competition between syn and anti acetonide formation. If the acetonides formed from any triol system are either syn or anti, then only allylic acetonides are favoured over non-allylic acetonnides. Only ribo-triol system formed six membered syn acetonides (thermodynamic control). No triol has produced all the three acetonides. All the ring sizes were unambiguously confirmed by employing Evan's 13C NMR method supported by 1H NMR spectroscopy. These chiral building blocks with predefined stereochemistry and multiple functional groups can be potential scaffolds for total synthesis.

Difenoconazole (DFZ) is a widely used triazole fungicide in agricultural production. However, the presence of DFZ residue in the environment poses a significant risk to non-target organisms. Ferulic acid (FA) is a phenolic compound known for its antioxidant and anti-inflammatory properties. This study aims to investigate the hepatic damage caused by DFZ in carp and explore the mechanism through which FA alleviates this damage. The findings revealed that FA enhanced the antioxidant capability of the carp's liver and reduced the accumulation of reactive oxygen species (ROS) in the liver tissue. Moreover, FA regulated the transcriptional levels of inflammation-related factors, effectively preventing the inflammatory response triggered by the NF-κB signaling pathway. Additionally, TUNEL results demonstrated that DFZ initiated apoptosis, while dietary supplementation with FA decreased the protein expression levels of Bax and Cytochrome C (Cyt c) and the transcriptional levels of bax, caspase3, caspase9, p53 genes. Furthermore, FA increased the protein expression and transcriptional levels of Bcl-2. In conclusion, FA protects against liver injury induced by DFZ exposure in carp by modulating oxidative damage, inflammation, and apoptosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Efficient synthesis of CF3‐functionalized 1,3‐dioxolane phosphonates via base‐catalyzed nucleophilic addition/cyclization of diethyl ethynylphosphonate or diethyl 3‐hydroxyprop‐1‐yn‐1‐ylphosphonates with trifluoromethylketones is described. Synthesis of various CF3‐substituted 1,3‐dioxolane derivatives in good to excellent yields with a broad range of substrates is described. [ABSTRACT FROM AUTHOR]

Synthesis of 1-[(2,2-dimethyl-1,3-dioxolan-4-yl)methyl]-1H-indole- -2,3-dione (10) was achieved by coupling 1H-indole-2,3-dione (16) with (R)- -(2,2-dimethyl-1,3-dioxolan-4-yl)methyl 4-methylbenzenesulfonate (15) in the presence of sodium hydride in dry N,N-dimethylformamide at room temperature in a closed Erlenmeyer flask. Condensation of 10 with hydrazinecarbothioamide in water afforded the thiosemicarbazone derivative 17; its subsequent cyclization with potassium carbonate in water gave the corresponding thione 18 in good yield. The 3-allylthio and 3-benzylthio derivatives 20 and 21 were also prepared by alkylating thiol 19 with alkyl halides in aqueous sodium hydroxide or coupling of 3-(allylthio/benzylthio)-5H-1,2,4-triazino[5,6-b]indoles (23 and 24) with compound 15 in NaH/DMF. Compound 20 was isomerized to a mixture of geometrical isomers (E/Z)-5-[(2,2-dimethyl-1,3-dioxolan-4-yl)- methyl]-3-(prop-1-en-1-ylthio)-5H-1,2,4-triazino[5,6-b]indoles (25 and 26), evidenced by their 1H- and 13C-NMR spectra taken in deuterodimethyl sulfoxide. Structural elucidation of the synthesized compounds was realized using FT-IR, 1H-NMR, 13C-NMR, mass spectrometry and elemental analysis. The newly synthesized compounds were found to possess moderate inhibitory activity against the fungus Candida albicans compared to clotrimazole as reference control. Compounds 10, 17, 19, 20, 21, 23 and 24 had mean growth inhibition zones (IZ) and minimal inhibitory concentrations (MIC) in the range of 12–15 mm and 31.25–200 μg mL-1, respectively, with inhibition levels in the range 70.58–88.23 %. Compound 19 exhibited moderate activity against Gram-positive bacteria Staphylococcus aureus relative to imipenem as the standard drug. All compounds were inactive against Escherichia coli and Pseudomonas aeruginosa.

A kinetic and mechanistical studies of the new pathway for competitive transformation of ethylene glycol by alumina and silica gel have been described. Commercial alumina (Al com), synthetic alumina (Al syn), commercial silica gel (Si com) and synthetic silica gel (Si syn) were used for the transformation of ethylene glycol to a mixture of diethylene glycol, 1,4-dioxane and 2-methyl-1,3-dioxolane via acetaldehyde by heating at 150 °C under autogenous pressure without solvent. The results show that the yield of these three products strongly depends on the nature of the used catalyst and the reaction time. [ABSTRACT FROM AUTHOR]

The hydrolysis of 2-methylbut-3-yn-2-yl carbamate gave 4,4-dimethyl-5-methylidene-1,3-dioxo-lan-2-one, whereas 2-methylbut-3-yn-2-ol was converted under similar conditions to 3-hydroxy-3-methylbutan-2-one. 2-[2-Amino(hydrazinyl)-6H-1,3,4-thiadiazin-5-yl]propan-2-yl carbamates were synthesized by reacting 4-bromo-2-methyl-3-oxobutan-2-yl carbamate with thiosemicarbazide and carbonothioic dihydrazide, respectively. [ABSTRACT FROM AUTHOR]

Background: Cobweb disease is a fungal disease that commonly affects the cultivation and production of edible mushrooms, leading to serious yield and economic losses. It is considered a major fungal disease in the realm of edible mushrooms. The symptoms of cobweb disease were found during the cultivation of Lyophyllum decastes. This study aimed to identify the causative pathogen of cobweb disease and evaluate effective fungicides, providing valuable insights for field control and management of L. decastes cobweb disease., Results: The causal agent of cobweb disease was isolated from samples infected and identified as Cladobotryum mycophilum based on morphological and cultural characteristics, as well as multi-locus phylogeny analysis (ITS, RPB1, RPB2, and TEF1-α). Pathogenicity tests further confirmed C. mycophilum as the responsible pathogen for this condition. Among the selected fungicides, Prochloraz-manganese chloride complex, Trifloxystrobin, tebuconazole, and Difenoconazole exhibited significant inhibitory effects on the pathogen's mycelium, with EC50 values of 0.076 µg/mL, 0.173 µg/mL, and 0.364 µg/mL, respectively. These fungicides can serve as references for future field control of cobweb disease in L. decastes., Conclusion: This study is the first report of C. mycophilum as the causing agent of cobweb disease in L. decastes in China. Notably, Prochloraz-manganese chloride complex demonstrated the strongest inhibitory efficacy against C. mycophilum., (© 2024. The Author(s).)

A "one-step" strategy has been demonstrated for the tunable synthesis of multifunctional aliphatic polycarbonates (APCs) with ethylene oxide (EO), ethylene carbonate (EC), and cyclohexene oxide (CHO) side groups by the copolymerization of 4-vinyl-1-cyclohexene diepoxide with carbon dioxide under an aminotriphenolate iron/PPNBz (PPN = bis(triphenylphosphine)-iminium, Bz = benzoate) binary catalyst. By adjusting the PPNBz-to-iron complex ratio and incorporating auxiliary solvents, the content of functional side groups can be tuned within the ranges of 53-75% for EO, 18-47% for EC, and <1-7% for CHO. The yield and molecular weight distribution of the resulting multifunctional APCs are affected by the viscosity of the polymerization system. The use of tetrahydrofuran as an auxiliary solvent enables the preparation of narrow-distribution polycarbonates at high conversion. This work presents a novel perspective for the preparation of tailorable multifunctional APCs.

Umbelliferous (Apiaceae) vegetables are widely consumed worldwide for their nutritive and health benefits. The main goal of the current study is to explore the compositional heterogeneity in four dried umbelliferous vegetables viz, celery, coriander, dill, and parsley targeting their volatile profile using gas chromatography-mass spectrometry (GC-MS). A total of 133 volatile metabolites were detected belonging to 12 classes. Aromatic hydrocarbons were detected as the major components of the analyzed vegetables accounting ca. 64.0, 62.4, 59.5, and 47.8% in parsley, dill, celery, and coriander, respectively. Aliphatic hydrocarbons were detected at ca. 6.39, 8.21, 6.16, and 6.79% in parsley, dill, celery, and coriander, respectively. Polyunsaturated fatty acids (PUFA) of various health benefits were detected in parsley and represented by roughanic acid and α-linolenic acid at 4.99 and 0.47%, respectively. Myristicin and frambinone were detected only in parsley at 0.45 and 0.56%. Investigation of antibacterial activity of umbelliferous vegetables n-hexane extract revealed a moderate antibacterial activity against Gram-positive and Gram-negative bacteria with higher activity for celery and dill against Staphylococcus aureus with inhibition zone 20.3 mm compared to 24.3 mm of the standard antibacterial drug., (© 2024. The Author(s).)

Ethnopharmacological Relevance: Perillae Folium, the leaves and twigs of Perilla frutescens (L.) Britton, has been included in many traditional Chinese medicine herbal formulas to treat depression. However, the precise antidepressant mechanism of the essential oil from Perillae Folium (PFEO) has not been fully investigated., Aim of the Study: To assess the effects and potential mechanisms of PFEO on depression using animal models and network pharmacology analysis., Materials and Methods: PFEO was intranasally administered to a mouse model of social defeat stress (SDS). The antidepressant effects of PFEO on SDS-induced mice were evaluated using behavioral tests. Enzyme-linked immunosorbent assay (ELISA) and western blot were performed to measure the levels of depression-related biomarkers in the hippocampus and serum of the mice. The chemical compounds of PFEO were determined using gas chromatography-mass spectrometry (GC-MS). Network pharmacology and molecular docking analyses were conducted to investigate the potential bioactive components of PFEO and the mechanisms underlying the antidepressant effects. To validate the mechanisms of the bioactive compounds, in vitro models using PC12 and BV2 cells were established and the blood-brain barrier (BBB) permeability was evaluated., Results: The intranasal administration of PFEO suppressed SDS-induced depression in mice by increasing the time spent in the social zone and the social interactions in the social interaction test and by decreasing the immobility time in the tail suspension and forced swimming tests. Moreover, the PFEO treatment reduced the SDS-induced anxiety-like behavior, as inferred from the increased activity in the central zone observed in the open field test and in the open arms observed in the elevated plus maze test. PFEO administration recovered the SDS-induced decrease in the levels of 5-HT, NE, gamma-aminobutyric acid (GABA), and p-ERK in the hippocampus of mice. Furthermore, the increased serum corticosterone level was also attenuated by the PFEO treatment. A total of 21 volatile compounds were detected in PFEO using GC-MS, among which elemicin (15.52%), apiol (15.16%), and perillaldehyde (12.79%) were the most abundant ones. The PFEO compounds targeted 32 depression-associated genes, which were mainly related to neural cells and neurotransmission pathways. Molecular docking indicated good binding affinities between the bioactive components of PFEO (apiol, β-caryophyllene, elemicin, and myristicin) and the key targets, including ACHE, IL1B, IL6, MAOB, SLC6A2, SLC6A3, SLC6A4, and tumor necrosis factor. Among the four compounds, β-caryophyllene, elemicin, and myristicin were more effective in reducing neurotoxicity and neuroinflammation. Elemicin showed the highest BBB permeability rate., Conclusions: This study shows the antidepressant activities of PFEO in an SDS-induced mouse model and suggests its potential mechanisms of action: regulation of the corticosterone levels, hippocampal neurotransmitters, and ERK signaling. Apiol, β-caryophyllene, elemicin, and myristicin may be the main contributors to the observed effects induced by PFEO. Further studies are needed to fully elucidate the underlying mechanisms and the main PFEO bioactive components., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Numerous anti-seizure medications (ASMs) have been developed to treat Dravet syndrome (DS). This network meta-analysis aimed to comprehensively analyse the efficacy of ASMs in DS patients, especially in non-seizure-free patients after treatment., Methods: PubMed, EMBASE, Cochrane Library, and Chinese National Knowledge Infrastructure databases were searched. The treatment efficacy was assessed by the percentage reduction in monthly convulsive seizure frequency (MCSF) from baseline or individuals who achieved at least a 50 % or 75 % reduction from baseline in convulsive seizure frequency (CSF)., Results: Six randomised controlled trials with 633 participants and seven regimens based on four add-on ASMs-fenfluramine (FFA), stiripentol (STP), cannabidiol (CBD), and soticlestat-were included. All drug regimens were superior to the placebo at achieving at least 50 % and 75 % reductions in CSF, but only STP, 0.4 mg/kg/d FFA (FFA0.4), and 0.7 mg/kg/d FFA (FFA0.7) reduced MCSF. STP (50 mg/kg/d) had the highest correlation with reducing MCSF and achieving at least a 50 % reduction from baseline in CSF, followed by FFA0.4 and FFA0.7. Soticlestat and CBD may also be effective in reducing seizures in DS patients., Conclusion: STP can be recommended as the first choice among the included drug regimens for reducing seizures in DS patients, while FFA0.4 may be considered the second choice. Other drug regimens can be used as alternative treatments. STP, FFA0.4, and FFA0.7 may consistently present favourable efficacy in most DS patients, while other regimens may present prominent inter-individual variability. Appropriate dose selection and intense monitoring are necessary when treating DS using these drugs., Competing Interests: Declaration of competing interest All authors declare that they have no conflict of interest., (Copyright © 2024 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

Difenoconazole has a widespread agricultural use to control fungal diseases in crops, including rice. In edge-of-field surface waters the residues of this lipophilic fungicide may be toxic to both pelagic and benthic organisms. To allow an effect assessment we mined the regulatory and open literature for aquatic toxicity data. Since published sediment toxicity data were scarce we conducted 28 d sediment-spiked toxicity test with 8 species of benthic macroinvertebrates. Ecotoxicological threshold levels for effects were assessed by applying the species sensitivity distribution approach. Based on short-term L(E)C 50 's for aquatic organisms from water-only tests an acute Hazardous Concentration to 5% of the species (HC 5 ) of 100 µg difenoconazole/L was obtained, while the HC 5 based on chronic NOEC values was a factor of 104 lower (0.96 µg difenoconazole/L). For benthic macroinvertebrates the chronic HC 5 , based on 28d-L(E)C 10 values, was 0.82 mg difenoconazole/kg dry weight sediment. To allow a risk assessment for water- and sediment-dwelling organisms, exposure concentrations were predicted for the water and sediment compartment of an edge-of-field pond bordering rice paddies treated with difenoconazole using the Chinese Top-Rice modelling approach, the Chinese Nanchang exposure scenario and the Equilibrium Partitioning theory. It appeared that in the vast majority of the 20 climate years simulated, potential risks to aquatic and sediment organisms cannot be excluded. Although the HC 5 values based on laboratory toxicity data provide one line of evidence only, our evaluation suggests population- and community-level effects on these organisms due to chronic risks in particular., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Xiao hui Yin reports a relationship with National Natural Science Foundation of China (Grant nos. 32372579, 21007060) that includes: funding grants. Peng fei Xiao reports a relationship with Ji Yang college of Zhejiang Agriculture and Forestry University Science developmental foundation(Grant no.4251700015) that includes: funding grants. Xiao hui Yin reports a relationship with Natural Science Foundation of Zhejiang Province (Grant no. LY14B070014) that includes: funding grants., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Liver fibrosis occurs due to injury or inflammation, which results in the excessive production of collagen and the formation of fibrotic scar tissue that impairs liver function. Despite the limited treatment options available, freshwater clams may hold promise in the treatment of liver fibrosis. In this study, we demonstrated the effects of ethanol extract of freshwater clam (FCE), ethyl acetate extract of FCE (EA-FCE), and trans-2-nonadecyl-4-(hydroxymethyl)-1,3-dioxolane (TNHD) on liver fibrosis induced by dimethylnitrosamine (DMN). Administration of FCE and TNHD alleviated liver injury, including tissue damage, necrosis, inflammation scores, fibrosis scores, serum enzymes, and triglyceride levels. Furthermore, we analyzed the expression of fibrosis-related proteins, such as α-smooth muscle actin (α-SMA) and transforming growth factor (TGF-β), as well as the hydroxyproline content, which decreased after treatment with FCE and TNHD. Animal experiments revealed that FCE and TNHD can reduce liver fibrosis by inhibiting cytokines that activate stellate cells and decreasing extracellular matrix (ECM) secretion. Cell experiments have shown that TNHD inhibits the MAPK/Smad signaling pathway and TGF-β1 activation, resulting in a reduction in the expression of fibrosis-related proteins. Therefore, freshwater clam extracts, particularly TNHD, may have potential therapeutic and preventive effects for the amelioration of liver fibrosis.

Difenoconazole (DFZ) is a fungicidal pesticide extensively employed for the management of fungal diseases in fruits, vegetables, and cereal crops. However, its potential environmental impact cannot be ignored, as DFZ accumulation is able to lead to aquatic environment pollution and harm to non-target organisms. Quercetin (QUE), a flavonoid abundant in fruits and vegetables, possesses antioxidant and anti-inflammatory properties. In this article, carp were exposed to 400 mg/kg QUE and/or 0.3906 mg/L DFZ for 30 d to investigate the effect of QUE on DFZ-induced respiratory toxicity in carp. Research shows that DFZ exposure increases reactive oxygen species (ROS) production in the carp's respiratory system, leading to oxidative stress, inflammation, and damage to gill tissue and tight junction proteins. Further research demonstrates that DFZ induces mitochondrial dynamic imbalance and gill cell apoptosis. Notably, QUE treatment significantly reduces ROS levels, alleviates oxidative stress and inflammation, and mitigates mitochondrial dynamics imbalance and mitochondrial apoptosis. This study emphasizes the profound mechanism of DFZ toxicity to the respiratory system of common carp and the beneficial role of QUE in mitigating DFZ toxicity. These findings contribute to a better understanding of pesticide risk assessment in aquatic systems and provide new insights into strategies to reduce their toxicity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

As a broad-spectrum and efficient triazole fungicide, difenoconazole is widely used, which not only pollutes the environment but also exerts toxic effects on non-target organisms. The spleen plays an important role in immune protection as an important secondary lymphoid organ in carp. In this study, we assessed the protective impact of silybin as a dietary additive on spleen tissues of carp during exposure to difenoconazole. Sixty carp were separated into four groups for this investigation including control group, difenoconazole group, silybin group, and silybin and difenoconazole group. By hematoxylin-eosin staining, dihydroethidium staining, immunohistochemical staining, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay, quantitative real-time PCR assay, Western blot analysis, biochemical assays, and immune function indicator assays, we found that silybin could prevent difenoconazole-induced spleen tissue damage, oxidative stress, and immune dysfunction, and inhibited apoptosis of carp spleen tissue cells by suppressing the formation of p53-driven caspase-9-apoptotic protease activating factor-1-cytochrome C complex. The results suggested that silybin as a dietary additive could improve spleen tissue damage and immune dysfunction induced by difenoconazole in aquaculture carp., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Until recently, one of the reasons for the unsatisfactory characterization of alicyclic ketals of aliphatic and alkylaromatic ketones was the absence of any mention of the presence of such compounds in natural samples. Another reason is in the low yields of such ketals on the interaction of ketones and diols under the conditions of conventional acid catalysis. To optimize the synthesis of trace amounts of such ketals, we used cobalt(II) bromide and dimethyl glyoxime as catalysts. The simplest chromatographic parameters, including the difference between the retention indices of the products and the starting compounds (difference in retention indices, DRI), are effective for identifying the target ketals in reaction mixtures. Such combined chromatography–mass spectrometric characteristics as homologous increments of retention indices (iRI) are informative not only for the group identification of analytes (assignment to the corresponding homologous series) and the assessment of their molecular weights (at low-intense signals of molecular ions). They are also useful for the determination of the total number of branches of the sp3-carbon skeleton of molecules (N) using the regression of N ≈ aiRI + b. [ABSTRACT FROM AUTHOR]

The series of the interaction products of substituted benzaldehydes XC6H4CHO with several aliphatic diols (ethanediol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, and racemic 2,3-butanediol) were characterized for the first time by analytical parameters required for their chromatography–mass spectrometric identification: electron ionization mass spectra and gas-chromatographic retention indices (RIs) on a standard nonpolar polydimethylsiloxane stationary phase. It was found that it is expedient to combine this characterization of new compounds with controlling the correctness of the RIs by checking their correlations with data for one or several series of simpler and, therefore, characterized in more detail structural analogs. The proposed algorithm made it possible not only to confirm the correctness of all of the newly determined retention indices but also to reveal an erroneous reference value of the retention index of 4-ethoxyphenol. An appropriate selection of structural analogs provides an opportunity to use this method for controlling the retention indices of compounds in whose molecules steric interactions of structural fragments are manifested. [ABSTRACT FROM AUTHOR]

Water and the organic solvents tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, 1-propanol, 2-propanol, tert-butanol, acetonitrile, or acetone are completely miscible in all proportions at room temperature. Here, we present new buffering-out phase separation systems that the above mentioned organic aqueous solutions can be induced to form two liquid phases in the presence of a biological buffer 2-[[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl]amino]ethanesulfonic acid (TES). The lower liquid phase is rich in water and buffer, and the upper phase is organic rich. This observation has both practical and mechanistic interests. The phase diagrams of these systems were constructed by experimental measurements at ambient conditions. Molecular dynamic (MD) simulations were performed for TES + water + THF system to understand the interactions between TES, water, and organic solvent at molecular level. Several composition-sets for this system, beyond and inside the liquid-liquid phase-splitting region, have been simulated. Interestingly, the MD simulation for compositions inside the phase separation region showed that THF molecules are forced out from the water network to start forming a new liquid phase. The hydrogen-bonds, hydrogen-bonds lifetimes, hydrogen-bond energies, radial distribution functions, coordination numbers, the electrostatic interactions, and the van der Waals interactions between the different pairs have been calculated. Additionally, MD simulations for TES + water + tert-butanol/acetonitrile/acetone phase separation systems were simulated. The results from MD simulations provide an explanation for the buffering-out phenomena observed in [TES + water + organic solvent] systems by a mechanism controlled by the competitive interactions of the buffer and the organic solvent with water. The molecular mechanism reported here is helpful for designing new benign separation materials. [ABSTRACT FROM AUTHOR]

The reactions of 4-[(4-formylphenoxy)methyl] derivatives of ethyl 6-alkyl(phenyl)-substituted nicotinates with primary amines, glycols and 1,2-phenylenediamine, leading to the formation of the corresponding azomethines, 1,3-dioxolanes, and 2,3-dihydrobenzylimidazoles with preparative yields were studied. The synthesized azomethines were selectively reduced into the corresponding secondary amines with sodium triacetoxyborohydride in benzene at 20–25°C. The composition and structure of the synthesized compounds was established by elemental analysis and IR and 1H and 13C NMR spectroscopy. [ABSTRACT FROM AUTHOR]

Pesticides represent a serious problem for agricultural workers due to their neurotoxic effects. The aim of this study was to evaluate the ability of pharmacological oxidative phosphorylation uncouplers to reduce the effect of the difenoconazole fungicide on mitochondrial DNA (mtDNA) of various organs in mice. Injections of difenoconazole caused cognitive deficits in mice, and the protonophore 2,4-dinitrophenol (2,4-DNP) and Azur I (AzI), a demethylated metabolite of methylene blue (MB), prevented the deterioration of cognitive abilities in mice induced by difenoconazole. Difenoconazole increased the rate of reactive oxygen species (ROS) production, likely through inhibition of complex I of the mitochondrial respiratory chain. After intraperitoneal administration of difenoconazole lungs, testes and midbrain were most sensitive to the accumulation of mtDNA damage. In contrast, the cerebral cortex and hippocampus were not tolerant to the effects of difenoconazole. The protonophore 2,4-DNP reduced the rate of ROS formation and significantly reduced the amount of mtDNA damage caused by difenoconazole in the midbrain, and partially, in the lungs and testes. MB, an alternative electron carrier capable of bypassing inhibited complex I, had no effect on the effect of difenoconazole on mtDNA, while its metabolite AzI, a demethylated metabolite of MB, was able to protect the mtDNA of the midbrain and testes. Thus, mitochondria-targeted therapy is a promising approach to reduce pesticide toxicity for agricultural workers.

Background: Assessment of the risk of pesticide inhalation in populations around farmland is necessary because inhalation is one of the ways in which pesticides can risk human health. This study aimed to identify the inhalation risk of difenoconazole on humans by using dose-response and exposure assessments., Results: In the field simulation application, respiratory exposure in populations around farmland ranged from 71 to 430 ng/m 3 . Using response surface methodology, the maximum bioaccessibility of difenoconazole in three simulated lung fluids was 35.33% in Gamble's solution (GS), 34.12% in artificial lysosomal fluid (ALF), and 42.06% in simulated interstitial lung fluid (SLF). Taking the proliferation activity of the A549 cell model as the endpoint, the benchmark dose limit and benchmark dose of difenoconazole on A549 cells were 16.36 and 5.60 mg/kg, respectively. The margin of exposure to difenoconazole in GS, ALF and SLF were, respectively, 8.66 × 10 5 to 5.28 × 10 6 , 8.97 × 10 5 to 5.47 × 10 6 and 7.28 × 10 5 to 4.44 × 10 6 ., Conclusion: The risk assessment results indicate that under all circumstances, applying difenoconazole is safe for populations around farmland. However, a fan-shaped nozzle, suspension concentrate and greater inhalation height increase the risk of inhalation. © 2023 Society of Chemical Industry., (© 2023 Society of Chemical Industry.)

Prulifloxacin, a broad-spectrum quinolone antibiotic, exhibits three distinct crystal forms, each with different bioavailability and therapeutic properties. It is imperative to assess and control the proportion of each crystal form during the production of raw materials and preparations. Therefore, it is necessary to establish an analytical method that can determine the content of each crystal form in the ternary polycrystalline mixtures. In this study, prulifloxacin crystal forms were analyzed and quantitatively measured using Raman spectroscopy. First, three pure crystal forms of prulifloxacin were prepared under different crystallization conditions and mixed into ternary mixtures at the designed proportions. Subsequently, the ternary mixed crystal samples were analyzed using a Raman microscope.Then run a partial least squares regression analysis to establish a PLS quantitative model using the average spectra data, and a non-negative least squares analysis to establish an area percentage quantitative model using Raman imaging data.The method validation results showed that the two models successfully predicted the proportion of each crystal form within the prulifloxacin polycrystalline mixtures, with a prediction accuracy of less than ± 10 %. Raman spectroscopy was thus established as an effective method for crystal form analysis and quantitative measurement of prulifloxacin., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Liwen ZHANG reports financial support was provided by Science and Technology Program of Guangzhou,Science and Technology Program of Guangzhou Municipal Public Security Bureau., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: Zika virus (ZIKV) is an emerging arbovirus that in recent years has been associated with cases of severe neurological disorders, such as microcephaly in newborns and Guillain-Barré syndrome in adults. As there is no vaccine or treatment, the search for new therapeutic targets is of great relevance. In this sense, plants are extremely rich sources for the discovery of new bioactive compounds and the species Phyllanthus brasiliensis (native to the Amazon region) remains unexplored., Purpose: To investigate the potential antiviral activity of compounds isolated from P. brasiliensis leaves against ZIKV infection., Methods: In vitro antiviral assays were performed with justicidin B (a lignan) and four glycosylated lignans (tuberculatin, phyllanthostatin A, 5-O-β-d-glucopyranosyljusticidin B, and cleistanthin B) against ZIKV in Vero cells. MTT colorimetric assay was used to assess cell viability and plaque forming unit assay to quantify viral load. In addition, for justicidin B, tests were performed to investigate the mechanism of action (virucidal, adsorption, internalization, post-infection)., Results: The isolated compounds showed potent anti-ZIKV activities and high selectivity indexes. Moreover, justicidin B, tuberculatin, and phyllanthostatin A completely reduced the viral load in at least one of the concentrations evaluated. Among them, justicidin B stood out as the main active, and further investigation revealed that justicidin B exerts its antiviral effect during post-infection stages, resulting in a remarkable 99.9 % reduction in viral load when treatment was initiated 24 h after infection., Conclusion: Our findings suggest that justicidin B inhibits endosomal internalization and acidification, effectively interrupting the viral multiplication cycle. Therefore, the findings shed light on the promising potential of isolated compounds isolated from P. brasiliensis, especially justicidin B, which could contribute to the drug development and treatments for Zika virus infections., Competing Interests: Declaration of Competing Interest The authors declare that is no conflict of interest., (Copyright © 2023 Elsevier GmbH. All rights reserved.)

In this study, we applied OMICs analysis to identify substance-specific biomarker candidates, which may act as early indicators for specific ecotoxic modes of actions (MoA). Zebrafish embryos were exposed to two sublethal concentrations of difenoconazole and metalaxyl according to a modified protocol of the OECD test guideline No. 236. At the end of exposure, total RNA and protein were extracted, followed by transcriptomics and proteomics analysis. The analysis of significantly differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) revealed a positive exposure-response correlation in all test concentrations for both fungicides. Similarly, also a positive correlation between the obtained transcriptome and proteome data was observed, highlighting the robustness of our approach. From the detected DEGs, candidate biomarkers specific for difenoconazole (apoa1b, gatm, mylpfb and acta1b) and metalaxyl (lgals2b, abat, fabp1b.1 and myh9a) were selected, and their biological functions were discussed to assess the predictive potential., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Syn dihydroxyketone motifs are embedded in a wide range of biologically active natural products, however the development of stereoselective synthetic methods to assemble these structures has proven a challenging task. We report a highly diastereoselective method for the synthesis of syn dihydroxyketones from propargylic alcohols, with wide scope for application in natural product synthesis. The reaction sequence involves regioselective cyclisation of propargylic alcohols with incorporation of a triketone to give enol dioxolanes that are then diastereoselectively epoxidised to form unusual spiroepoxide intermediates. Hydrolysis affords syn dihydroxyketones as essentially single diastereisomers. The reaction sequence is operationally simple, of wide substrate scope, and remarkably can be efficiently carried out as a one‐pot process with no loss of overall yield or diastereoselectivity. [ABSTRACT FROM AUTHOR]

In AgSbF6/Rh2(OAc)4/DCM system, two‐component reaction of 2‐diazo‐3,5‐dioxo‐6‐ynoates (sulfones) and two equivalent of aldehydes provided easy access to 2‐(1,3‐dioxolanes‐4‐yl)‐4H‐pyran‐4‐ones. This represents the first method for generating the novel heterocyclic compounds. A possible mechanism is proposed to explain this result. The most significant features of the tandem cyclization are simple procedure, mild conditions and high diastereoselectivity. [ABSTRACT FROM AUTHOR]

Over the last years, the human probable carcinogen 1,4-dioxane and alkyl-1,3-dioxanes and dioxolanes have been detected and identified as the cause of several pollution episodes in the Llobregat River (Catalonia, NE Spain) and its aquifer. It is an issue of major concern to study these compounds which are released to the environment by resin manufacturing plants' spills and wastewater discharges spread along rivers and reach drinking water treatment plants (DWTPs) in order to protect the environment and public health. In this study four seasonal sampling campaigns were carried out over a year to determine the removal efficiency of the dioxanes and dioxolanes at each step of a DWTP including ozonation, granular activated carbon filters, ultrafiltration and reverse osmosis step's treatments. Additionally, a weekly sampling monitoring of 1,4-dioxane and alkyl-1,3-dioxanes and dioxolanes in raw water, groundwater and finished water was performed at a DWTP over more than two years. Aqueous odor concentration thresholds (OTCs) were established by the three-alternative forced choice method (3-AFC). Following a previous published methodology, samples were analyzed and results showed that the advanced treatment (Ultrafiltration followed by reverse osmosis) line removes more efficiently 1,4-dioxane, alkyl dioxanes and dioxolanes (80 ± 6% for 1,4-dioxane, 97 ± 7% for 5,5-DMD and 100 ± 0% for 2,5,5-TMD) than the upgraded conventional treatment line (ozonation followed by granular activated carbon filters) (−12 ± 50%, 25 ± 62% and 50 ± 51% respectively), where some desorption processes were eventually observed. From the monitoring study, results suggest that the presence of 1,4-dioxane is not only due to spills, but also from other sources of contamination. Whereas dioxolanes almost completely disappeared in time, 1,4-dioxane's concentrations remained low and fluctuant. A background concentration of 1,4-dioxane in surface waters (∼1 μg/L) has been determined with a relevant concentration up to 11.6 μg/L of 1,4-dioxane in groundwater. The perception values for some of the studied compounds were extremely low (few ng/L only), which confirms the relevancy of this group of compounds as malodorous agents in waters. Image 1 • Determination of dioxanes and dioxolanes in a DWTP intake was performed for 3 years. • Chronic pollution by 1,4-dioxane in Llobregat River has been demonstrated. • Aqueous odor thresholds concentrations of 2-EDD and 2,5,5-TMD were at low ng/L. • Removals in a DWTP with advanced treatment processes were determined. • Advanced processes showed better removal efficiencies than conventional processes. [ABSTRACT FROM AUTHOR]

Ether‐based electrolytes are commonly used in Li–O2 batteries (LOBs) because of their relatively high stability. But they are still prone to be attacked by superoxides or singlet oxygen via hydrogen abstract reactions, which leads to performance decaying during long‐term operation. Herein we propose a methylated cyclic ether, 2,2,4,4,5,5‐hexamethyl‐1,3‐dioxolane (HMD), as a stable electrolyte solvent for LOBs. Such a compound does not contain any hydrogen atoms on the alpha‐carbon of the ether, and thus avoids hydrogen abstraction reactions. As the result, this solvent exhibits excellent stability with the presence of superoxide or singlet oxygen. In addition the CO2 evolution during charge process is prohibited. The LOB with HMD‐based electrolyte was able to run up to 157 cycles, 4 times more than with 1,3‐dioxolane (DOL) or 1,2‐dimethoxyethane (DME) based electrolytes. [ABSTRACT FROM AUTHOR]

Syntheses of α-branched alkyl and aryl substituted 9-[2-(phosphonomethoxy)ethyl]purines from substituted 1,3-dioxolanes have been developed. Key synthetic precursors, α-substituted dialkyl [(2-hydroxyethoxy)methyl]phosphonates were prepared via Lewis acid mediated cleavage of 1,3-dioxolanes followed by reaction with dialkyl or trialkyl phosphites. The best preparative yields were achieved under conditions utilizing tin tetrachloride as Lewis acid and triisopropyl phosphite. Attachment of purine bases to dialkyl [(2-hydroxyethoxy)methyl]phosphonates was performed by Mitsunobu reaction. Final α-branched 9-[2-(phosphonomethoxy)ethyl]purines were tested for antiviral, cytostatic and antiparasitic activity, the latter one determined as inhibitory activity towards Plasmodium falciparum enzyme hypoxanthine-guanine-xanthine phosphoribosyltransfesase. In most cases biological activity was only marginal. [ABSTRACT FROM AUTHOR]

Generalized results of the analysis of synthesis reaction of cyclic acetals of 1,3-dioxolane series by condensation of cyclohex-3-ene-1-carbaldehydes with 1,2-propanediol and its 3- chloro-, 3-chloroalkoxy derivatives, as well as their epoxidation, bromination, dichlorocarbenylation on C=C bond of cycle and dienophilic activity were presented. The influence of the nature of substituents on relative reactivity of reacting components and efficiency of the prepared products as the ED-20-based active diluent of the polymer composition has been considered. [ABSTRACT FROM AUTHOR]