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1.
J Chromatogr A ; 1645: 462130, 2021 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-33848663

RESUMO

Inspired by the outstanding functions of 3-aminopropyltriethoxysilane (APTES), which can be used for functionalization of both covalent organic frameworks (COFs) and substrate surfaces, herein, a proof-of-concept demonstration was carried out by one-step synthesis and immobilization of COF-1 in capillary. COF-1 was grown on the inner wall of capillary using APTES, which played a triple role of catalyst, stabilizer, and connecting arm during the process. The immobilization of COF-1 on silicon surface was confirmed by scanning electron microscopy. Moreover, COF-1 modified capillary (COF-1@capillary) column exhibited excellent performance in the electrochromatographic separation of amino acids. High resolution and separation efficiency (225,378 plates/m for 4-methylbiphenyl) were successfully achieved. Separation of methylbenzene, styrene, ethylbenzene, chlorobenzene, 1,2-dichlorobenzene, 1,2,4-trichlorobenzene, 4-methylbiphenyl, naphthalene, and 4-vinylbipheny in the electro-driven mode confirmed the successful growth of COF-1 on the inner wall of capillary. The developed facile method for the immobilization of COF-1 may pave the way for further application prospects of boron-based COFs.


Assuntos
Eletrocromatografia Capilar/métodos , Estruturas Metalorgânicas/química , Derivados de Benzeno/análise , Derivados de Benzeno/química , Derivados de Benzeno/isolamento & purificação , Boro/química , Propilaminas/química , Silanos/química
2.
Eur J Med Chem ; 214: 113230, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33581553

RESUMO

To continue our ongoing studies on discovery of new potent antifungal leads, 43 novel pyrazole-aromatic containing carboxamides were rationally designed and synthesized. Bioassays indicated that most target compounds displayed good in vitro antifungal activities against Botrytis cinerea, Rhizoctonia cerealis and Sclerotinia sclerotiorum and in vivo antifungal activity against R. solani. Compound 11ea exhibited the most significant in vitro activity against R. cerealis (EC50 = 0.93 µg/mL) with about 2-fold more potent than a previously reported lead compound A1 (EC50 = 2.01 µg/mL), and about 11-fold more potent than the positive control/commercial succinate dehydrogenase inhibitor thifluzamide (EC50 = 23.09 µg/mL). Structure-activity relationship analysis and molecular docking simulations indicated that the presence of difluoromethyl pyrazole-(m-benzene) carboxamide scaffold obviously increased the antifungal activity. The further enzymatic bioassay showed that both thifluzamide and compound 11ea displayed excellent SDH inhibitory effects, and fluorescence quenching analysis suggested that they may share the same target SDH.


Assuntos
Antifúngicos/farmacologia , Basidiomycota/enzimologia , Derivados de Benzeno/farmacologia , Inibidores Enzimáticos/farmacologia , Pirazóis/farmacologia , Succinato Desidrogenase/antagonistas & inibidores , Antifúngicos/síntese química , Antifúngicos/química , Ascomicetos/efeitos dos fármacos , Basidiomycota/efeitos dos fármacos , Derivados de Benzeno/síntese química , Derivados de Benzeno/química , Botrytis/efeitos dos fármacos , Relação Dose-Resposta a Droga , Desenho de Fármacos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Humanos , Testes de Sensibilidade Microbiana , Simulação de Acoplamento Molecular , Estrutura Molecular , Pirazóis/síntese química , Pirazóis/química , Relação Estrutura-Atividade , Succinato Desidrogenase/metabolismo
3.
Nat Commun ; 12(1): 812, 2021 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-33547279

RESUMO

Carbon dots (CDs) are photoluminescent nanomaterials with wide-ranging applications. Despite their photoactivity, it remains unknown whether CDs degrade under illumination and whether such photodegradation poses any cytotoxic effects. Here, we show laboratory-synthesized CDs irradiated with light degrade into molecules that are toxic to both normal (HEK-293) and cancerous (HeLa and HepG2) human cells. Eight days of irradiation photolyzes 28.6-59.8% of the CDs to <3 kilo Dalton molecules, 1431 of which are detected by high-throughput, non-target high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. Molecular network and community analysis further reveal 499 cytotoxicity-related molecules, 212 of which contain polyethylene glycol, glucose, or benzene-related structures. Photo-induced production of hydroxyl and alkyl radicals play important roles in CD degradation as affected by temperature, pH, light intensity and wavelength. Commercial CDs show similar photodegraded products and cytotoxicity profiles, demonstrating that photodegradation-induced cytotoxicity is likely common to CDs regardless of their chemical composition. Our results highlight the importance of light in cytocompatibility studies of CDs.


Assuntos
Carbono/toxicidade , Citotoxinas/toxicidade , Pontos Quânticos/toxicidade , Derivados de Benzeno/química , Derivados de Benzeno/toxicidade , Carbono/química , Carbono/efeitos da radiação , Sobrevivência Celular/efeitos dos fármacos , Citotoxinas/química , Glucose/química , Glucose/toxicidade , Células HEK293 , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Radical Hidroxila/química , Radical Hidroxila/toxicidade , Cinética , Luz , Fotólise , Polietilenoglicóis/química , Polietilenoglicóis/toxicidade , Pontos Quânticos/química , Pontos Quânticos/efeitos da radiação , Temperatura
4.
Food Chem ; 338: 127988, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-32950866

RESUMO

The potential for tristyrylphenol ethoxylates (TSPEOs) residues to contaminate crops or be released into the environment is of increasing concern, as they are toxic to living organisms. This study determined the dissipation of TSPEO homologues in cucumber under field conditions. TSPEOn (n = 6-29) dissipated more rapidly in cucumber than in soil samples, with half-lives of 1.80-4.30 d and 3.73-6.52 d, respectively. Short-chain TSPEOn (n = 6-11) persisted for longer than other oligomers in soil. Concentrations of the final residues (∑TSPEOs) in cucumber and soil were 24.3-1349 µg/kg and 47.3-1337 µg/kg, respectively. TSP15EO or TSP16EO was the dominant oligomer, with concentrations of 2.30-150 µg/kg. The risk assessment showed that the acute and chronic dietary exposure risks of ∑TSPEOs in cucumber were 0.03-0.57% and 0.05-0.39%, respectively, suggesting little or no health risk to Chinese consumers.


Assuntos
Derivados de Benzeno/análise , Derivados de Benzeno/química , Cucumis sativus/química , Dieta , Solo/química , Estirenos/análise , Estirenos/química , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/química , Medição de Risco , Poluentes do Solo/análise , Poluentes do Solo/química
5.
Chem Asian J ; 15(7): 1022-1024, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32034862

RESUMO

We have demonstrated B2 pin2 as superior deoxidizing agent for the reductive deoxygenation of quinol derivatives under basic conditions. A wide range of highly functionalized phenols were obtained in good yields including a complex drug molecule, which revealed the high functional group tolerance of this protocol.


Assuntos
Hidrocarbonetos Aromáticos/química , Hidroquinonas/química , Oxigênio/química , Derivados de Benzeno/química , Compostos de Boro/química , Oxirredução , Fenóis
6.
Org Lett ; 22(4): 1665-1669, 2020 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-32017583

RESUMO

Silyl triflate precursors to benzyne and related intermediates have emerged as valuable synthetic building blocks. However, data addressing the safety of employing these silyl triflate precursors are lacking. We report the calorimetric analysis of a typical Kobayashi procedure for forming and trapping benzyne using a silyl triflate precursor. Our findings suggest that, unlike benzenediazonium carboxylate precursors to benzyne, silyl triflates may be employed under mild conditions without severe concern for runaway reaction.


Assuntos
Derivados de Benzeno/síntese química , Silanos/química , Derivados de Benzeno/química , Estrutura Molecular , Estereoisomerismo
7.
J Chromatogr A ; 1618: 460928, 2020 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-32008822

RESUMO

This work presents a new triptycene-based stationary phase (TP-PEG) combining the three-dimensional (3D) triptycene (TP) framework with polyethylene glycol (PEG) moieties for gas chromatographic (GC) separations. Its statically coated capillary column showed high column efficiency of 5263 plates/m determined by naphthalene at 120 °C. Its Rohrschneider-McReynolds constants and Abraham solvation system constants were measured to characterize its polarity and molecular interactions with analytes of different types. As evidenced, the TP-PEG column showed high-resolution performance for the isomers of anilines, phenols, halobenzenes and alkanes with distinct advantages over the PEG columns, particularly those critical isomers such as 3,5-/2,3-xylidine (R = 2.94), m-/p-chlorotoluene (R = 1.92), p-/m-cresol (R = 1.89), 2,2-dimethylbutane/2-methylpentane (R = 1.51), 2,2,3-trimethylbutane /2,3-dimethyl pentane (R = 1.74) and 2,3-dimethylpentane/n-heptane (R = 1.92). In addition, it exhibited good column repeatability and reproducibility with the relative standard deviation (RSD) values of 0.02%-0.09% for run-to-run, 0.13%-0.22% for day-to-day and 2.7%-4.1% for column-to-column, respectively, and a wide operational temperature range (30 °C-280 °C) . Its application to GC-MS analysis of the essential oil of Osmanthus fragrans has proven its good potential for practical analysis of complex samples.


Assuntos
Antracenos/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Óleos Voláteis/química , Oleaceae/química , Polietilenoglicóis/química , Alcanos/análise , Alcanos/química , Compostos de Anilina/análise , Compostos de Anilina/química , Derivados de Benzeno/química , Isomerismo , Fenóis/análise , Fenóis/química , Reprodutibilidade dos Testes
8.
Anal Bioanal Chem ; 412(8): 1769-1784, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32043201

RESUMO

Simultaneous speciation of benzenediol isomers (BDIs), 1,2-benzenediol (catechol, CC), 1,3-benzenediol (resorcinol, RS), and 1,4-benzenediol (hydroquinone, HQ), was investigated by differential pulse voltammetry (DPV) using a graphite paste electrode (GPE) modified with Prussian blue-polyaniline nanocomposite. The modified GPE showed good stability, sensitivity, and selectivity properties for all the three BDIs. Prussian blue-doped nanosized polyaniline (PBNS-PANI) was synthesized first by using mechanochemical reactions between aniline and ferric chloride hexahydrate as the oxidants and then followed by the addition of potassium hexacyanoferrate(II) in a solid-state and template-free technique. The material was characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The DPV measurements are performed in phosphate electrolyte solution with pH 4.0 at a potential range of - 0.1 to 1.0 V. The proposed modified electrode displayed a strong, stable, and continuous three well-separated oxidation peaks towards electrooxidation at potentials 0.20, 0.31, and 0.76 V for HQ, CC, and RS, respectively. The calibration curves were linear from 1 to 350.5 µM for both HQ and CC, while for RS, it was from 2 to 350.5 µM. The limit of detection was determined to be 0.18, 0.01, and 0.02 µM for HQ, CC, and RS, respectively. The analytical performance of the PBNS-PANI/GPE has been evaluated for simultaneous determination of HQ, CC, and RS in creek water, commercial hair dye, and skin whitening cream samples with satisfactory recoveries between 90 and 106%. Overall, we demonstrated that the presence of NS-PANI and PB resulted in a large redox-active surface area that enabled a promising analytical platform for simultaneous detection of BDIs. Graphical abstract.


Assuntos
Compostos de Anilina/química , Derivados de Benzeno/análise , Ferrocianetos/química , Nanoestruturas/química , Derivados de Benzeno/química , Calibragem , Eletrodos , Humanos , Concentração de Íons de Hidrogênio , Isomerismo , Cinética , Limite de Detecção , Espectroscopia de Infravermelho com Transformada de Fourier
9.
J Chromatogr A ; 1616: 460804, 2020 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-31973929

RESUMO

We report on a direct comparison of the separation performance in capillary nano-LC between commercial packed bed columns and the small-domain silica monoliths in applications. Octadecylsilylated monolithic silica capillary columns with a 50 and 100 µm inner diameter (i.d.) were prepared with a procedure providing domain sizes in the sub-2 µm range. The fabricated monolith columns could provide plate heights (H) of 4.0‒4.2 µm for hexylbenzene (retention factor (k) = 3.6) at an optimal linear velocity range under an isocratic condition, while showing a column permeability (Kv0 = 1.6‒1.8 × 10-14 m2) comparable to that of a column packed with 3‒3.5 µm particles. When the peak capacity (np) for a cytochrome C digest was compared for variable gradient times (tG = 15, 30, 60, and 120 min) and constant gradient steepness (b'), the present monolith columns could show a 30‒40% higher np-value than the packed capillary column with 2 µm particles (e.g. np = 180 versus np = 259 at tG = 30 min). The produced monolith columns showed a high chromatographic repeatability for both isocratic and gradient elution (e.g. relative standard deviation (n = 3, RSD (%)) = 0.5% for H, 2,6% for k, and 5.6% for Kv0 in the isocratic mode using the 100 µm i.d.-columns). The present results show that the domain sizes which can now be achieved for capillary silica monoliths are sufficiently small to result in separation efficiencies that can successfully compete with the commercial packed bed columns available for use in nano-LC applications.


Assuntos
Cromatografia Líquida/métodos , Nanotecnologia/métodos , Tamanho da Partícula , Dióxido de Silício/química , Derivados de Benzeno/química , Citocromos c/análise
10.
Molecules ; 25(2)2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31952313

RESUMO

Herein, we present a short and highly modular synthetic route that involves 8-aminoquinoline directed C-H arylation and transamidation chemistry, and which enables access to a wide range of elaborate benzofuran-2-carboxamides. For the directed C-H arylation reactions, Pd catalysis was used to install a wide range of aryl and heteroaryl substituents at the C3 position of the benzofuran scaffold in high efficiency. Directing group cleavage and further diversification of the C3-arylated benzofuran products were then achieved in a single synthetic operation through the utilization of a one-pot, two-step transamidation procedure, which proceeded via the intermediate N-acyl-Boc-carbamates. Given the high efficiency and modularity of this synthetic strategy, it constitutes a very attractive method for generating structurally diverse collections of benzofuran derivatives for small molecule screening campaigns.


Assuntos
Amidas/química , Aminoquinolinas/química , Derivados de Benzeno/química , Benzofuranos/química , Catálise , Estrutura Molecular
11.
J Am Chem Soc ; 142(7): 3540-3547, 2020 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-31986022

RESUMO

Covalent organic frameworks (COFs) are commonly synthesized under harsh conditions yielding unprocessable powders. Control in their crystallization process and growth has been limited to studies conducted in hazardous organic solvents. Herein, we report a one-pot synthetic method that yields stable aqueous colloidal solutions of sub-20 nm crystalline imine-based COF particles at room temperature and ambient pressure. Additionally, through the combination of experimental and computational studies, we investigated the mechanisms and forces underlying the formation of such imine-based COF colloids in water. Further, we show that our method can be used to process the colloidal solution into 2D and 3D COF shapes as well as to generate a COF ink that can be directly printed onto surfaces. These findings should open new vistas in COF chemistry, enabling new application areas.


Assuntos
Estruturas Metalorgânicas/síntese química , Água/química , Aldeídos/química , Derivados de Benzeno/química , Biomimética/métodos , Coloides/síntese química , Coloides/química , Cristalização , Iminas/síntese química , Iminas/química , Micelas , Tamanho da Partícula
12.
Org Biomol Chem ; 18(7): 1369-1376, 2020 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-31996878

RESUMO

This paper discloses a transition metal-free selective C-H dithiocarbamation of drug skeletons using disulfiram (DSF) in the presence of KI/K2S2O8 in DMF/H2O. Drug skeletons, including 5-aminopyrazoles, indoles, pyrroloquinoline, and Julolidine, underwent C-H dithiocarbamation smoothly to afford a variety of drug-like molecules in moderate to good yields. It was found that the in situ formed 5-aminopyrazole iodide is the key intermediate for the dithiocarbamation. Bioassay results show that some of these N-heterocyclic dithiocarbamate derivatives exhibit good antifungal activity against Colletotrichum gloeosprioides and Fusarium oxysporum, F. proliferatum, Fusarium solani, Geotrichum candidum, Penicillium digitatum, Penicillium italicum, Phyricularia grisea.


Assuntos
Antifúngicos/farmacologia , Colletotrichum/efeitos dos fármacos , Fusarium/efeitos dos fármacos , Geotrichum/efeitos dos fármacos , Penicillium/efeitos dos fármacos , Tiocarbamatos/farmacologia , Antifúngicos/síntese química , Antifúngicos/química , Derivados de Benzeno/química , Testes de Sensibilidade Microbiana , Estrutura Molecular , Estereoisomerismo , Tiocarbamatos/síntese química , Tiocarbamatos/química
13.
Anal Chim Acta ; 1098: 86-93, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31948590

RESUMO

Cytochrome P450 (CYP450), and in particular CYP3A4, is the most abundantly expressed CYP450 isozyme implicated in many drug-drug and medicinal plant-drug interactions. Therefore, incorporation of CYP3A4 enzyme screening at an early stage of drug discovery is preferable in order to avoid enzymatic interactions. Here we present for the first time a paper-based CYP3A4 immobilized sol-gel-derived a platform using resorufin benzyl ether as a fluorogenic enzyme substrate used to investigate enzyme activity. The fluorescence intensity of the product can be simply quantified by using a handheld digital microscope and an image analysis software. The limit of quantitation was 0.35 µM with good precision (RSDs < 4.1%). Furthermore, the assay of CYP3A4 activity on the developed paper-based device provided comparable results with those obtained from conventional well-plates (p > 0.05), while offering simplicity and lower cost. Kinetic parameters of the immobilized CYP3A4 in sol-gel coated paper were calculated from the Lineweaver-Burk plot, including Michaelis constant (Km) and maximum velocity (Vmax), which were 2.71 ±â€¯0.35 µM and 0.43 ±â€¯0.05 µM/min, respectively. Moreover, a functional test of these devices was conducted by assessments of known CYP3A4 inhibitors (i.e. ketoconazole, itraconazole) and inducers (i.e. phenytoin, carbamazepine). To further demonstrate the broad range of uses, the devices were utilized to assay plant extracts i.e. Areca catechu seeds, Camellia sinensis leaves, Eclipta prostrata aerial part, providing results in good agreement with previous studies. Furthermore, the sol-gel immobilized enzyme stored at 4 °C can increase storage stability, offering the activity of 86.3 ±â€¯0.4% after 3-weeks storage, equivalent to the activity of the free enzyme solution after 1-week storage. The developed paper-based devices offer versatility, portability and low-cost.


Assuntos
Derivados de Benzeno/química , Sistema Enzimático do Citocromo P-450/análise , Enzimas Imobilizadas/análise , Éteres/química , Oxazinas/química , Papel , Sistema Enzimático do Citocromo P-450/metabolismo , Ativação Enzimática , Enzimas Imobilizadas/metabolismo , Géis/química , Humanos , Estrutura Molecular
14.
Chem Commun (Camb) ; 56(8): 1179-1182, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31868184

RESUMO

We report unprecedented Friedel-Crafts arylation of chlorofullerenes C60Cl6 and C70Cl8 with unprotected carboxylic acids as an efficient single-step synthesis of the inherently stable water-soluble fullerene derivatives. Using this method, a series of previously unaccessible compounds was obtained without chromatographic purification in almost quantitative yields. Promising anti-HIV activity comparable to characteristics of commercial drugs was demonstrated for some of these compounds.


Assuntos
Fármacos Anti-HIV/farmacologia , Ácidos Carboxílicos/farmacologia , Fulerenos/farmacologia , Água/química , Fármacos Anti-HIV/síntese química , Fármacos Anti-HIV/química , Derivados de Benzeno/síntese química , Derivados de Benzeno/química , Derivados de Benzeno/farmacologia , Ácidos Carboxílicos/síntese química , Ácidos Carboxílicos/química , Linhagem Celular Tumoral , Fulerenos/química , HIV-1/efeitos dos fármacos , HIV-2/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Solubilidade , Tiofenos/síntese química , Tiofenos/química , Tiofenos/farmacologia
15.
J Chromatogr A ; 1614: 460700, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31740031

RESUMO

In recent years, supercritical fluid chromatography (SFC) has become a powerful tool in modern analytical chemistry, and the diversity of stationary phases in SFC promotes phenyl-type phases to confront with a significant resurgence of interest. In this paper, a series of phenyl-type stationary phases with different substituted benzenes involving N-propylbenzamide (PB), 4-fluoro-N-propylbenzamide (PB-F), and 4-ethyl-N-propylbenzamide (PB-ET) were synthesized. Retention mechanism of these phases in SFC was investigated using a linear solvation energy relationship (LSER) model. The phenyl-type stationary phases with all positive parameters can provide all types of interaction, typically involving hydrogen bonding, dipole-dipole and dispersive interactions. The different benzene's substituents of the stationary phases mainly affected their hydrogen bonding and dipole-dipole interactions, which could be reflected by the angle between the solvation vectors to some extent. The k-k plot showed that the selectivity difference of phenyl-type stationary phases was closely related to the type of solute. Thus, based on twenty-five natural phenolic compounds, two systems with high orthogonality (63.49%) were constructed using three columns, namely phenyl column (PHE) × PB-F and PB × PB-F. Finally, after investigating the influence of chromatographic conditions, ten flavonoids could be separated by using PB, PB-F and PHE columns in SFC.


Assuntos
Cromatografia com Fluido Supercrítico/métodos , Fenóis/química , Derivados de Benzeno/química , Cromatografia com Fluido Supercrítico/instrumentação , Fenóis/isolamento & purificação
16.
J Chromatogr A ; 1614: 460714, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31761436

RESUMO

Developing highly selective stationary phases is essential to address the issues for separation of analytes with similar properties and various components in complex samples. Herein, we report a new triptycene-based material functionalized with polycaprolactone moieties (TP-PCL) as the stationary phase with high-resolution performance for gas chromatography (GC). The TP-PCL capillary column exhibited column efficiency of 5555 plates/m and moderate polarity. On the column, dozens of mixtures of positional and structural isomers can be well resolved, involving benzene derivatives with varying substituents (alkyl, halo, nitro, hydroxyl, amino), naphthalene derivatives, alkanes and alcohols. It exhibits advantageous performance for high resolution of the critical pairs of alkylbenzenes, phenols, anilines and alkanes over the PCL column and commercial DB-35 MS column with similar polarity. Moreover, the TP-PCL column showed excellent separation repeatability and reproducibility with RSD values of 0.02%-0.07% for run-to-run (n = 4), 0.11%-0.18% for day-to-day (n = 4) and 2.1%-4.7% for column-to-column (n = 4). In addition, it exhibited distinctly enhanced thermal stability in contrast to the PCL column. Its application to analysis of the essential oil from Artemisiae argyi proves its good potential for practical use.


Assuntos
Antracenos/química , Cromatografia Gasosa/métodos , Poliésteres/química , Álcoois/análise , Álcoois/química , Alcanos/análise , Alcanos/química , Compostos de Anilina/análise , Compostos de Anilina/química , Derivados de Benzeno/análise , Derivados de Benzeno/química , Isomerismo , Naftalenos/análise , Naftalenos/química , Fenóis/análise , Fenóis/química , Reprodutibilidade dos Testes
17.
Int J Mol Sci ; 20(22)2019 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-31703381

RESUMO

Deposition of soluble proteins as insoluble amyloid fibrils is associated with a number of pathological states. There is a growing interest in the identification of small molecules that can prevent proteins from undergoing amyloid fibril formation. In the present study, a series of small aromatic compounds with different substitutions of 1,3,5-triphenylbenzene have been synthesized and their possible effects on amyloid fibril formation by hen egg white lysozyme (HEWL), a model protein for amyloid formation, and of their resulting toxicity were examined. The inhibitory effect of the compounds against HEWL amyloid formation was analyzed using thioflavin T and Congo red binding assays, atomic force microscopy, Fourier-transform infrared spectroscopy, and cytotoxicity assays, such as the 3-(4,5-Dimethylthiazol)-2,5-Diphenyltetrazolium Bromide (MTT) reduction assay and caspase-3 activity measurements. We found that all compounds in our screen were efficient inhibitors of HEWL fibril formation and their associated toxicity. We showed that electron-withdrawing substituents such as -F and -NO2 potentiated the inhibitory potential of 1,3,5-triphenylbenzene, whereas electron-donating groups such as -OH, -OCH3, and -CH3 lowered it. These results may ultimately find applications in the development of potential inhibitors against amyloid fibril formation and its biologically adverse effects.


Assuntos
Amiloide/química , Proteínas Aviárias/química , Derivados de Benzeno/química , Muramidase/química , Agregados Proteicos , Animais , Linhagem Celular Tumoral , Galinhas , Humanos
18.
Molecules ; 24(23)2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31757106

RESUMO

This work deals with the formulation of environmentally friendly, cheap, and readily-available materials for green building applications, providing the function of air purificator by improving the safety and the comfort of an indoor environment. High surface area TiO2-SiO2 samples, prepared by a simple, cost effective, and scalable synthetic approach, proved to be effective in maximizing the properties of each component, i.e., the photocatalytic properties of titania and the high surface area of silica. TiO2 was introduced onto an ordered mesoporous silica Santa Barbara Amorphous-15 (SBA-15), that is featured by interesting insulating features, by using an incipient wetness impregnation method. The photocatalytic activity was evaluated in gas phase oxidation of ethylbenzene, which was selected as model volatile organic compound (VOC) molecule. The morphological, textural and structural features along with the electronic properties, the hydrophilicity and heat capacity of the materials were investigated in depth by scanning electron microscopy, powder X-ray diffraction, N2 physisorption, diffuse reflectance UV-Vis, FT-IR spectroscopies, and modulated DSC (MDSC) dynamic scan. Outstanding performances in the ethylbenzene abatement results are promising for further application in the green building sector.


Assuntos
Poluentes Atmosféricos/química , Poluição do Ar em Ambientes Fechados , Derivados de Benzeno/química , Materiais de Construção , Dióxido de Silício/química , Titânio/química , Oxirredução , Porosidade
19.
Int J Mol Sci ; 20(21)2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31694248

RESUMO

Nitrenium ions are common reactive intermediates with high activities towards some biological nucleophiles. In this paper, we employed femtosecond transient absorption (fs-TA) and nanosecond transient absorption (ns-TA) as well as nanosecond time-resolved resonance Raman (ns-TR3) spectroscopy and density function theory (DFT) calculations to study the spectroscopic properties of the N(4,4'-dibromodiphenylamino)-2,4,6-trimethylpyridinium BF4- salt (1) in an acidic aqueous solution. Efficient cleavage of the N-N bond (4 ps) to form the N,N-di(4-bromophenyl)nitrenium ion (DN) was also observed in the acidic aqueous solution. As a result, the dication intermediate 4 appears more likely to be produced after abstracting a proton for the nitrenium ion DN in the acid solution first, followed by an electron abstraction to form the radical cation intermediate 3. These new and more extensive time-resolved spectroscopic data will be useful to help to develop an improved understanding of the identity, nature, and properties of nitrenium ions involved in reactions under acidic aqueous conditions.


Assuntos
Derivados de Benzeno/química , Imidas/química , Ácidos/química , Teoria da Densidade Funcional , Halogenação , Íons/química , Modelos Moleculares , Análise Espectral Raman/métodos , Água/química
20.
J Chem Inf Model ; 59(11): 4750-4763, 2019 11 25.
Artigo em Inglês | MEDLINE | ID: mdl-31589815

RESUMO

Applications of computational methods to predict binding affinities for protein/drug complexes are routinely used in structure-based drug discovery. Applications of these methods often rely on empirical force fields (FFs) and their associated parameter sets and atom types. However, it is widely accepted that FFs cannot accurately cover the entire chemical space of drug-like molecules, due to the restrictive cost of parametrization and the poor transferability of existing parameters. To address these limitations, initiatives have been carried out to develop more transferable methods, in order to allow for more rigorous descriptions of any drug-like molecule. We have previously reported H-TEQ, a method which does not rely on atom types and incorporates well established chemical principles to assign parameters to organic molecules. The previous implementation of H-TEQ (a torsional barrier prediction method) only covered saturated and lone pair containing molecules; here, we report our efforts to incorporate conjugated systems into our model. The next step was the evaluation of the introduction of unsaturations. The developed model (H-TEQ3.0) has been validated on a wide variety of molecules containing heteroaromatic groups, alkyls, and fused ring systems. Our method performs on par with one of the most commonly used FFs (GAFF2), without relying on atom types or any prior parametrization.


Assuntos
Compostos Alílicos/química , Derivados de Benzeno/química , Descoberta de Drogas , Conformação Molecular , Simulação de Dinâmica Molecular , Preparações Farmacêuticas/química , Teoria Quântica , Termodinâmica
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