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Synthesis of Hydroxybenzodiazepines with Potential Antioxidant and Antifungal Action
Benzodiazepines derivatives are nitrogen heterocyclic compounds that have various industrial, synthetic, and medicinal applications. Therefore, its potential fully justifies every effort towards the improvement of new, selective, and competent production of these heterocyclic compounds. The novelty of this study encompasses the synthesis of new hydroxylated analogs of 1,5-benzodiazepine together with the evaluation of their biological potential as antioxidants and antifungals candidates. Additionally, the reported antifungal activity against fungi of the Sporothrix schenckii complex inaugurates an unprecedented property fo...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research

Multivariate Optimization of Extraction Variables of PAH in Particulate Matter (PM10) in Indoor/Outdoor Air at Campos dos Goytacazes, Brazil
This study aims to evaluate the presence of outdoor and indoor PAH in 10 µm particulate matter (PM10) at one university in Campos dos Goytacazes. PM10 samples were collected from January to November 2018. Samples were extracted using an ultrasonic probe and analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The ideal extraction conditions (3 min; 150 W ; 50 mL) were defined by 23 full factorial design. The analysis showed a significant PM10 level increase (23.19 to 34.50 µg m-3 in outdoor, and 15.15 to 31.66 µg m-3 in indoor samples) and higher total PAH concentration in the harvesting season (outdoor:...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research

Magnetic and Mesoporous Silica-Niobia Material as Modifier of Carbon Paste Electrode for p-Nitrophenol Electrochemical Determination
In the present work, the sol-gel synthesis method was employed as strategy to obtain a magnetic and mesoporous silica-niobia material. The planned synthesis was based on the hetero-condensation of niobium and silicon alkoxide precursors, in the presence of spherical magnetite particles. The resulting material presented interesting characteristics such as magnetism, large mesopores, in the range from 20 to 50 nm, and 68 m2 g-1 of surface area. These features allowed its use as modifier of carbon paste electrode for p-nitrophenol determination, since niobia has never been used in electrochemical sensors for the determination...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research

Single-Layered Paper-Based Microfluidic Devices Made by Paint-Spraying Technique with Great Barrier Resistance for Colorimetric Assays
The single-layered paint-spraying paper based microfluidic devices (sp- μ PADs) have been for the first time integrated with the colorimetric assay. The polymethyl methacrylate (PMMA) board was applied as the mask instead of the iron mask, reducing the power requirement of the cutting machine. The paint was sprayed into the paper, which blocked the pores of the paper and constructed the hydrophobic barrier on the paper. The paint barrier was highly resistant to the various kind of chemicals and the minimum channel dimensions was 1.4 mm. By using the PMMA masks with different designs, the sp- μ PADs with different designs...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research

Evaluation of the Direct Interaction between Amino Acids and Glutathione-Coated CdTe Quantum Dots and Application in Urinalysis for Histidine Determination
The present work aimed to direct amino acid (AA) sensing by quantum dots (QD) and development of an analytical method for potential fast clinical tests. Notably, AA with a positive charge or neutral polar chains, namely L-histidine (His) and L-threonine (Thr), responded to glutathione-coated CdTe (GSH-CdTe) ( Δ F ≤ 90%, variation of fluorescence intensity). However, in ammoniacal buffer (0.25 mol L-1) at pH 8.0, 2.2 nm GSH-CdTe responded only to His. Static quenching with complex association constant (Ksv) varying from 2.81 to 0.94 (10 L mol-1) as well as van der Waals forces and/or hydrogen bonding were predicted for ...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research

Synthesis of 1,2,3-Triazole Benzophenone Derivatives and Evaluation of in vitro Sun Protection, Antioxidant Properties, and Antiproliferative Activity on HT-144 Melanoma Cells
Benzophenones display several biological activities, including antioxidant, anticancer, and photoprotective. Furthermore, antioxidants can minimize both ultraviolet absorption and tumor development. In the present investigation, a series of twenty-six 1,2,3-triazole-benzophenone derivatives were synthesized and had their antioxidant, anticancer, and photoprotective effects evaluated. For the compounds synthesis, 4,4 ’ -dihydroxybenzophenone (1a) and 2,4-dihydroxybenzophenone (1b) were propargylated, affording the alkynes bis(4-(prop-2-yn-1-yloxy))benzophenone (2a) and (2-hydroxy-4-(prop-2-yn-1-yloxy))benzophenone (2b), r...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research

Spectrophotometric Determination of Allura Red AC and Tartrazine in Food Products Using Hydrophobic Deep Eutectic Solvents as an Environmentally Sustainable Micro-Extractor
This paper reports the application of hydrophobic deep eutectic solvents (HDES) as an environmentally friendly alternative for liquid-phase microextraction (LPME) of Allura Red AC and Tartrazine in food products and the spectrophotometric determination of these analytes. The HDES used in this work were prepared by mixing octanoic acid (OctAc) or decanoic acid (DecAc) and tetrabutylammonium bromide (N4444-Br) in a molar ratio of 2:1. An investigation was also carried out regarding the effects of sample pH, sample volume, HDES volume, and concomitants on the analytical performance of the proposed method. The analytical curve...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research

Evaluation of Antibacterial Activity, Chromatographic Analysis for Rutin and Quercetin Quantification Using HPLC-UV-Vis from the Hydro-Alcoholic Extract Obtained from Bidens pilosa Linné
Novel and miniaturized technique, a dynamic sonication-assisted solvent extraction before the analysis by high performance liquid chromatography-ultraviolet visible (HPLC-UV-Vis) for isolation, identification and quantification of rutin and quercetin metabolites in alcoholic extracts from Bidens pilosa Linn é, was developed. The results showed that the flowers have a greater quantity of both analytes than other parts of the plant (e.g., leaves, stem and roots), the results were corroborated by liquid chromatography-mass spectrometry (LC-MS). In addition, the developed extraction technique against trad itional methods for ...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research

Structure-Physical Properties Relationship of Eutectic Solvents Prepared from Benzyltriethylammonium Chloride and Carboxylic Acids
Deep eutectic solvents (DESs) have attracted the attention of the researchers as alternative solvents due to desirable properties such as easy preparation and high thermal stability. In this work, it was reported the preparation of five DESs from benzyltriethylammonium chloride (BTEAC) as quaternary ammonium salt (QAS) and carboxylic acids (oxalic, malonic or benzoic) as hydrogen bonding donor (HBD), which four were not reported so far. Furthermore, it was presented the first type III liquid DES at room temperature from benzoic acid and shown by interaction energy calculations why the formation of benzyltriethylammonium ch...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research

Organic Matter Leached from Tropical Soils by Simulated Rain, Hard (NaOH) and Soft (NaNO3) Extractions: A Realistic Study about Risk Assessment in Soils
Alkaline extractions from humic material are used to risk assessment in soils. However, there are questions about the type of extraction most suitable for this evaluation. Thus, this work evaluated different soil extractions in search of realistic environmental conditions (simulated rain). The parameters obtained revealed significant differences between the levels and structural characteristics of organic matter, depending on the extractant used, reinforcing the importance of developing methodologies and analytical procedures that minimize structural changes and may be more representative of the molecular structures of org...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research

HSCCC Separations of Rutin Esters Obtained by Enzymatic Reaction Catalyzed by Lipase
The flavonoid rutin presents several pharmacological effects, despite this, its application in the pharmaceutical industry can be significantly limited by its low bioavailability. The development of lipophilic derivatives by esterification of hydroxyl groups with fatty acid chains may be an effective strategy to change their physicochemical properties. This work aims to use high-speed countercurrent chromatography (HSCCC) to isolate rutin esters produced by esterification reactions catalyzed by the immobilized lipase from Candida antarctica (Novozyme 435 ®). The lipase-catalyzed synthesis of rutin esters (R3-R18:2) in 2-m...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research

Identification of Synthetic Drugs on Seized Blotter Papers Using ATR-FTIR and PLS-DA: Routine Application in a Forensic Laboratory
Blotter papers seizures containing synthetic drugs have intensified over the last decades. These drugs were originally conceived as “ legal ” alternatives to traditional illicit drugs, designed to mimic their effects and circumvent control agencies. Reference methods for determining these substances on blotter papers are based on chromatographic techniques using mass spectrometry detection. However, these procedures are destructive, expensive, and time consuming. Some compounds are also thermolabile and not suitable for regular gas chromatography analyses. In this paper, two multivariate models were presented and inco...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research

New Greener Method for the Preparation of Heteropolyacid Compounds (HPW) Modified with Metallic Tin and Application in the Lactic Acid Esterification Reaction
The main objective of this work was to design an innovative method to prepare heterogeneous heteropolyacid catalysts. The heteropolyacid H3PW12O40 (HPW) was modified with tin(II) by two methodologies: a conventional aqueous ion-exchange (CS) and a redox solid-state (SS). In both cases, Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) measurements evidenced that Keggin structure was preserved. All materials were active in the esterification of lactic acid with several alcohols and a mechanism was proposed. The best results were obtained for octanol and benzyl alcohol, where higher conversion values...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research

Synthesis, Spectroscopic Characterization, DFT Calculations and Preliminary Antifungal Activity of New Piperine Derivatives
Four new piperine derivatives, PC1-PC4, were synthesized, and their structures were fully characterized by infrared (IR) and 1H and 13C nuclear magnetic resonance (NMR) spectroscopies. Quantum chemical calculations were performed using density functional theory (DFT) with the B3LYP-D3/6-31G(d,p) and 6-311+G(2d,p) basis sets. Electronic properties, such as the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) and some global chemical reactivity descriptors, were evaluated to study the reactivity and stability of the compounds. 1H and 13C NMR chemical shifts w...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research

Synthesis and Biological Evaluation of Benzo[f]indole-4,9-diones N-Linked to Carbohydrate Chains as New Type of Antitumor Agents
In this work, we report the synthesis of three series of carbohydrate-based benzo[f]indole-4,9-diones and amino-1,4-naphthoquinone derivatives and evaluated their cytotoxic activity against eight human cancer cell lines. Several compounds showed a promising cytotoxic activity toward the tumor cell lines (half maximal inhibitory concentration (IC50)< 10.0 μ M). The importance of the substitution pattern of the quinone derivatives on the antitumor activity was also discussed. 3-Carboethoxy-2-methyl-benzo[f]indole-4,9-dione derivatives were more cytotoxic than their parent compounds and amino-1,4-naphthoquinones. Unlike c...
Source: Journal of the Brazilian Chemical Society - March 1, 2021 Category: Chemistry Source Type: research