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1.
Chem Commun (Camb) ; 56(10): 1605-1607, 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-31939465

RESUMO

We report the first preparation of a monoclonal antibody (mAb) that can immobilize a palladium (Pd)-complex. The allylic amination reaction using a supramolecular catalyst consisting of the Pd-complex and mAb selectively gives the (R)-enantiomer product with an enantiomeric excess (ee) of 98 ± 2%. This is in sharp contrast to the reaction catalyzed by a conventional Pd-catalyst (ee < 2%).


Assuntos
Anticorpos Monoclonais/química , Complexos de Coordenação/química , Paládio/química , Compostos Alílicos/síntese química , Compostos Alílicos/química , Aminação , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/metabolismo , Benzilaminas/síntese química , Benzilaminas/química , Catálise , Bovinos , Complexos de Coordenação/imunologia , Complexos de Coordenação/metabolismo , Reações Cruzadas/imunologia , Feminino , Gastrópodes/química , Hemocianinas/química , Camundongos Endogâmicos BALB C , Ligação Proteica , Ródio/química , Soroalbumina Bovina/química , Estereoisomerismo , Água/química
2.
J Asian Nat Prod Res ; 22(1): 61-68, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31311320

RESUMO

We present the synthesis of enantiomerically pure (S)-α-methyl-serine methyl ester hydrochloride from 2-methyl-3-((4-(trifluoromethyl)benzyl)oxy)propanal and di-p-chlorobenzyl azodicarboxylate via asymmetrically catalyzed amination with naphthylalanine derivative catalyst. The application of the organocatalyst of D-3-(1-Naphthyl)-alanine is the key step in the synthesis and ensures the product is obtained with high levels of stereocontrol.


Assuntos
Serina , Aminação , Catálise , Estrutura Molecular , Serina/análogos & derivados , Estereoisomerismo
3.
Chem Commun (Camb) ; 55(87): 13096-13099, 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31612162

RESUMO

A fluorescence "turn-on" method for digestion-free analysis of 4-thiouridine (s4U) in nucleic acids was developed in this work based on the oxidative amination of s4U by fluoresceinamine (FAM-NH2) and periodate (IO4-). It was 125-fold more sensitive for s4U detection than the traditional UV330 absorption method, and showed excellent selectivity to s4U over 2-thiouridine (s2U) analogues and biological thiols.


Assuntos
Fluorescência , Ácidos Nucleicos/química , Tiouridina/análise , Aminação , Estrutura Molecular , Oxirredução
4.
Chem Commun (Camb) ; 55(91): 13653-13656, 2019 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-31593201

RESUMO

Blending synthetic biology and synthetic chemistry represents a powerful approach to diversity complex molecules. To further enable this, compatible synthetic tools are needed. We report the first Buchwald Hartwig amination reactions with unprotected halotryptophans under aqueous conditions and demonstrate this methodology is applicable also to the modification of unprotected tripeptides and the natural product barettin.


Assuntos
Oligopeptídeos/química , Peptídeos Cíclicos/química , Triptofano/análogos & derivados , Água/química , Aminação , Compostos de Anilina/química , Catálise , Halogênios/química , Oligopeptídeos/síntese química , Paládio/química , Triptofano/síntese química
5.
Int J Mol Sci ; 20(16)2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31430981

RESUMO

A library of isopulegol-based bi-, tri- and tetrafunctional chiral ligands has been developed from commercially available (-)-isopulegol and applied as chiral catalysts in the addition of diethylzinc to benzaldehyde. Michael addition of primary amines towards α-methylene-γ-butyrolactone, followed by reduction, was accomplished to provide aminodiols in highly stereoselective transformations. Stereoselective epoxidation of (+)-neoisopulegol, derived from natural (-)-isopulegol, and subsequent oxirane ring opening with primary amines afforded aminodiols. The regioselective ring closure of N-substituted aminodiols with formaldehyde was also investigated. Hydroxylation of (+)-neoisopulegol resulted in diol, which was then transformed into aminotriols by aminolysis of its epoxides. Dihydroxylation of (+)-neoisopulegol or derivatives with OsO4/NMO gave neoisopulegol-based di-, tri- and tetraols in highly stereoselective reactions. The antimicrobial activity of aminodiol and aminotriol derivatives as well as di-, tri- and tetraols was also explored. In addition, structure-activity relationships were examined by assessing substituent effects on the aminodiol and aminotriol systems.


Assuntos
/síntese química , 4-Butirolactona/síntese química , 4-Butirolactona/química , Aminação , Amino Álcoois/síntese química , Amino Álcoois/química , Benzaldeídos/síntese química , Benzaldeídos/química , Catálise , Técnicas de Química Sintética , Ligantes , Compostos Organometálicos/síntese química , Compostos Organometálicos/química , Estereoisomerismo
6.
Nat Commun ; 10(1): 3717, 2019 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-31420547

RESUMO

Amine dehydrogenases (AmDHs) catalyse the conversion of ketones into enantiomerically pure amines at the sole expense of ammonia and hydride source. Guided by structural information from computational models, we create AmDHs that can convert pharmaceutically relevant aromatic ketones with conversions up to quantitative and perfect chemical and optical purities. These AmDHs are created from an unconventional enzyme scaffold that apparently does not operate any asymmetric transformation in its natural reaction. Additionally, the best variant (LE-AmDH-v1) displays a unique substrate-dependent switch of enantioselectivity, affording S- or R-configured amine products with up to >99.9% enantiomeric excess. These findings are explained by in silico studies. LE-AmDH-v1 is highly thermostable (Tm of 69 °C), retains almost entirely its catalytic activity upon incubation up to 50 °C for several days, and operates preferentially at 50 °C and pH 9.0. This study also demonstrates that product inhibition can be a critical factor in AmDH-catalysed reductive amination.


Assuntos
Aminoácido Oxirredutases/síntese química , Geobacillus stearothermophilus/enzimologia , Cetonas/metabolismo , Aminação , Aminas , Amônia/metabolismo , Biocatálise , Desaminação , Estereoisomerismo
7.
ACS Chem Biol ; 14(7): 1481-1489, 2019 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-31259519

RESUMO

Efficient methods for the site-specific installation of structurally defined interstrand cross-links in duplex DNA may be useful in a wide variety of fields. The work described here developed a high-yield synthesis of chemically stable interstrand cross-links resulting from a reductive amination reaction between an abasic site and the noncanonical nucleobase 2-aminopurine in duplex DNA. Results from footprinting, liquid chromatography-mass spectrometry, and stability studies support the formation of an N2-alkylamine attachment between the 2-aminopurine residue and the Ap site. The reaction performs best when the 2-aminopurine residue on the opposing strand is offset 1 nt to the 5'-side of the abasic site. The cross-link confers substantial resistance to thermal denaturation (melting). The cross-linking reaction is fast (complete in 4 h), employs only commercially available reagents, and can be used to generate cross-linked duplexes in sufficient quantities for biophysical, structural, and DNA repair studies.


Assuntos
2-Aminopurina/química , Reagentes para Ligações Cruzadas/química , DNA/química , Aminação , Modelos Moleculares , Conformação de Ácido Nucleico , Desnaturação de Ácido Nucleico , Oxirredução
8.
Int J Biol Macromol ; 136: 106-114, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31185240

RESUMO

Magnetic nanoparticles coated with polymer shell containing reactive functional groups are of great interest especially as substrates for immobilization of ligands in biomedicine and catalysis. This article describes synthesis of novel functional MNPs coated with aminated starch via simple, fast and efficient method of functionalization of the surface by one-minute pounding in mortar. The concept is based on simplifying the synthesis of the magnetic support and obtaining a material that allows for effective bioligand immobilization. Basing on our previous research in the area of MNPs synthesis and biomedical applications, the high yield (149.96 mg/g of support) and effective immobilization of HSA was demonstrated for these nanoparticles without loss of protein activity. Obtained materials were characterized with ATR-FTIR spectroscopy, scanning (SEM) and transmission (TEM) electron microscopy, dynamic light scattering (DLS), X-ray diffraction, TGA-DTA and SQUID analysis. The developed method allows for modification of polysaccharides and nanoparticles towards materials enriched with amino groups in a quick and easy way. It can be expected that this method of quick solvent-free amination will find application in the chemistry of materials and polymers. In addition, the new obtained amino-rich MNPs may find use as carriers for the immobilization of bioligands in catalysis and pharmaceutical analysis.


Assuntos
Proteínas Imobilizadas/química , Nanopartículas de Magnetita/química , Polímeros/química , Albumina Sérica Humana/química , Amido/química , Aminação , Humanos , Proteínas Imobilizadas/metabolismo , Cinética , Polissacarídeos/química , Albumina Sérica Humana/metabolismo , Propriedades de Superfície , Temperatura Ambiente
9.
J Plant Physiol ; 239: 83-91, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31229903

RESUMO

In higher plants ammonium (NH4+) assimilation occurs mainly through the glutamine synthetase/glutamate synthase (GS/GOGAT) pathway. Nevertheless, when plants are exposed to stress conditions, such as excess of ammonium, the contribution of alternative routes of ammonium assimilation such as glutamate dehydrogenase (GDH) and asparagine synthetase (AS) activities might serve as detoxification mechanisms. In this work, the in vivo functions of these pathways were studied after supplying an excess of ammonium to tomato (Solanum lycopersicum L. cv. Agora Hybrid F1) roots previously adapted to grow under either nitrate or ammonium nutrition. The short-term incorporation of labelled ammonium (15NH4+) into the main amino acids was determined by GC-MS in the presence or absence of methionine sulphoximine (MSX) and azaserine (AZA), inhibitors of GS and GOGAT activities, respectively. Tomato roots were able to respond rapidly to excess ammonium by enhancing ammonium assimilation regardless of the previous nutritional regime to which the plant was adapted to grow. The assimilation of 15NH4+ could take place through pathways other than GS/GOGAT, since the inhibition of GS and GOGAT did not completely impede the incorporation of the labelled nitrogen into major amino acids. The in vivo formation of Asn by AS was shown to be exclusively Gln-dependent since the root was unable to incorporate 15NH4+ directly into Asn. On the other hand, an in vivo aminating capacity was revealed for GDH, since newly labelled Glu synthesis occurred even when GS and/or GOGAT activities were inhibited. The aminating GDH activity in tomato roots responded to an excess ammonium supply independently of the previous nutritional regime to which the plant had been subjected.


Assuntos
Compostos de Amônio/metabolismo , Glutamato Desidrogenase/metabolismo , Lycopersicon esculentum/metabolismo , Raízes de Plantas/metabolismo , Aminação , Compostos de Amônio/administração & dosagem , Fertilizantes , Lycopersicon esculentum/efeitos dos fármacos , Lycopersicon esculentum/enzimologia , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/enzimologia
10.
Sci Total Environ ; 679: 221-228, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31082595

RESUMO

As a widely used antiepileptic drug, carbamazepine (CBZ) has been frequently detected in aquatic environments, even in drinking water. Chloramine is a widely used alternative disinfectant due to its low-level formation of regulated disinfection byproducts (DBPs). However, there is previous evidence linking product mixtures of chloraminated CBZ to stronger DNA damage effects than those caused by CBZ itself. The present study further investigated the reaction rate, transformation mechanism and multi-endpoint toxicity of transformation products (TPs) of CBZ treated with NH2Cl under different pH conditions. The results showed that the reaction between CBZ and NH2Cl at pH 8.5, where NH2Cl is stable, is a second-order reaction with a rate of 4.2 M-1 h-1. Compared to both alkaline and acidic conditions, CBZ was quickly degraded at pH 7. This indicated that HOCl produced from NH2Cl hydrolysis is more effective in degrading CBZ than NH2Cl and NHCl2. Furthermore, the concentration variation of four TPs formed during the chloramination of CBZ under different pH conditions was investigate by quantitative analysis, and the transformation pathway from CBZ to 9(10H)-acridone was confirmed. Three of the detected TPs showed cytotoxicity, DNA damage effects or chromosome damage effects. Acridine and 9(10H)-acridone, which accumulated with increasing time, showed higher cytotoxic or genotoxic effects than CBZ itself. In addition, a similar transformation mechanism was observed in real ambient water during simulated chloramination with a low level of CBZ. These results suggested that despite the chloramination of CBZ being slower than chlorination, TPs with higher cytotoxicity or genotoxicity may lead to greater toxic risks.


Assuntos
Carbamazepina/toxicidade , Cloraminas/química , Poluentes Químicos da Água/toxicidade , Aminação , Anticonvulsivantes/química , Anticonvulsivantes/toxicidade , Carbamazepina/química , Citotoxinas/química , Citotoxinas/toxicidade , Desinfecção , Concentração de Íons de Hidrogênio , Cinética , Mutagênicos/química , Mutagênicos/toxicidade , Poluentes Químicos da Água/química
11.
Molecules ; 24(10)2019 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-31109114

RESUMO

Human serum albumin (HSA) is one of the most frequently immobilized proteins on the surface of carriers, including magnetic nanoparticles. This is because the drug-HSA interaction study is one of the basic pharmacokinetic parameters determined for drugs. In spite of many works describing the immobilization of HSA and the binding of active substances, research describing the influence of the used support on the effectiveness of immobilization is missing. There are also no reports about the effect of the support drying method on the effectiveness of protein immobilization. This paper examines the effect of both the method of functionalizing the polymer coating covering magnetic nanoparticles (MNPs), and the drying methods for the immobilization of HSA. Albumin was immobilized on three types of aminated chitosan-coated nanoparticles with a different content of amino groups long distanced from the surface Fe3O4-CS-Et(NH2)1-3. The obtained results showed that both the synthesis method and the method of drying nanoparticles have a large impact on the effectiveness of immobilization. Due to the fact that the results obtained for Fe3O4-CS-Et(NH2)2 significantly differ from those obtained for the others, the influence of the geometry of the shell structure on the ability to bind HSA was also explained by molecular dynamics.


Assuntos
Quitosana/química , Materiais Revestidos Biocompatíveis , Proteínas Imobilizadas , Nanopartículas de Magnetita , Albumina Sérica Humana , Adsorção , Aminação , Humanos , Proteínas Imobilizadas/química , Nanopartículas de Magnetita/química , Nanopartículas de Magnetita/ultraestrutura , Modelos Moleculares , Modelos Teóricos , Conformação Molecular , Polímeros/química , Albumina Sérica Humana/química , Solventes , Espectroscopia de Infravermelho com Transformada de Fourier
12.
Org Lett ; 21(10): 3813-3816, 2019 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-31021646

RESUMO

The Pd-catalyzed coupling of malonate nucleophiles with alkenes bearing tethered aryl or alkenyl triflates is described. These alkene difunctionalization reactions afford malonate-substituted cyclopentanes that contain fused aryl or cycloalkenyl rings. The transformations generate a five-membered ring, two C-C bonds, and provide products bearing up to three stereocenters with good chemical yield and generally high diastereoselectivity.


Assuntos
Alcenos/química , Ciclopentanos/síntese química , Paládio/química , Alquilação , Aminação , Catálise , Ciclopentanos/química , Malonatos , Estrutura Molecular
13.
Eur J Mass Spectrom (Chichester) ; 25(5): 412-418, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31006258

RESUMO

Histamine is an organic nitrogenous compound that acts as a neurotransmitter in the uterus, spinal cord, and brain and is involved in local immune responses. In this study, we developed a fast and simple derivatization method based on reductive amination that can be used to quantify histamine by hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry. Histamine isotope analogs were synthesized via reductive amination. Histamine was modified with H2-formaldehyde to form N-dimethylated histamine to act as a standard or with D2-formaldehyde to form N-dimethylated histamine-d4 to act as an internal standard. Using this method, we achieved a limit of detection of 3.6 ng/mL, a limit of quantification of 7.9 ng/mL, and a linear calibration curve with a coefficient of determination (R2) of 0.9987. Furthermore, the intra-day relative standard deviations ranged from 0.9% to 3.7% and the inter-day relative standard deviations ranged from 2.0% to 17.6%. After derivatization, N-dimethylated histamine showed 382.5% signal enhancement compared to unmodified histamine in mass spectrometry detection. To demonstrate the applicability of this method for biological samples, we utilized standard addition method to quantify histamine in fetal bovine serum and achieved a recovery of 86.7%.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Histamina/química , Espectrometria de Massas em Tandem/métodos , Aminação , Animais , Bovinos , Interações Hidrofóbicas e Hidrofílicas , Limite de Detecção , Soroalbumina Bovina/química
14.
Int J Biol Macromol ; 133: 412-419, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31004647

RESUMO

Ficin extract has been aminated using ethylenediamine and carbodiimide to transform all exposed carboxylic groups into amino groups, retaining around 80% of activity versus benzoyl-d,l-arginine p-nitroanilide hydrochloride (BANA) and 90% versus casein. This aminated enzyme was then immobilized on glyoxyl agarose beads. After optimization of the immobilization protocol (immobilization at pH 10 for just 1 h), the new biocatalyst was compared to that obtained using the non-aminated enzyme. Activity versus BANA was lower, but was higher versus casein. The new biocatalyst was more stable than the reference mainly at pH 7. The new biocatalyst permitted to have a more linear course and a higher hydrolysis yield of casein at 75 °C. Moreover, the activity of the new preparations was significantly higher than the reference or the free enzyme in 8 M urea, at pH 7 and 55 °C. The enzyme in an overloaded biocatalyst exhibited a much higher specific activity versus casein (75% of the low loaded biocatalysts) than the non-aminated enzyme (only 30%), suggesting a more appropriate enzyme orientation that decreased steric hindrances. Finally, the enzyme was reused for 5 cycles of casein hydrolysis at 40 °C and pH 7 without any decrease in enzyme activity.


Assuntos
Caseínas/metabolismo , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Ficina/química , Ficina/metabolismo , Glioxilatos/química , Sefarose/química , Aminação , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Hidrólise , Temperatura Ambiente
15.
Inorg Chem ; 58(9): 5956-5965, 2019 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-30986046

RESUMO

Stable five-coordinated (16-electron) half-sandwich iridium(III) and ruthenium(II) complexes are rarely reported, and their biological evaluations have not been considered to date. Herein, in an experiment designed to synthesize six-coordinated half-sandwich iridium(III) and ruthenium(II) complexes containing N,N-chelated α-keto-ß-diimine ligands, we observed the serendipitous formation of half-sandwich aminoimine iridium(III) and ruthenium(II) complexes via solvent-involved rearrangement reaction. These unsaturated 16-electron complexes had sufficient stability in DMSO-water solution. Moreover, no reaction with two-electron donors (CO and PPh3) and nucleobase (9-MeA and 9-EtG) was observed. Most of the complexes show good anticancer activities toward A549, HeLa, and HepG2 cancer cells, which are higher than the clinical drug cisplatin. The investigation of mechanism by flow cytometry showed that the complexes exert their anticancer efficacy by inducing apoptosis or necrosis, and increasing the intracellular ROS level. In addition, fluorescence property of these complexes makes it possible to investigate the microscopic mechanism by confocal microscopy. Notably, the complexes Ir3 and Ru1 enter A549 cancer cells through an energy-independent pathway, and they are mainly located in mitochondria and lysosomes.


Assuntos
Antineoplásicos/química , Complexos de Coordenação/química , Iminas/química , Irídio/química , Rutênio/química , Células A549 , Aminação , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Complexos de Coordenação/síntese química , Complexos de Coordenação/farmacologia , Cristalografia por Raios X , Células HeLa , Células Hep G2 , Humanos , Iminas/síntese química , Iminas/farmacologia , Irídio/farmacologia , Modelos Moleculares , Neoplasias/tratamento farmacológico , Rutênio/farmacologia
16.
Spectrochim Acta A Mol Biomol Spectrosc ; 218: 161-170, 2019 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-30986708

RESUMO

In order to improve the fluorescence properties of the green fluorescent protein chromophore, p­HOBDI ((5­(4­hydroxybenzylidene)­2,3­dimethyl­3,5­dihydro­4H­imidazol­4­one), sixteen dihydroimidazolone derivates were synthesized from thiohydantoin and arylaldehydes. The synthesis developed is an efficient, novel, one-pot procedure. The study provides a detailed description of the spectroscopic characteristics of the newly synthesized compounds, using p­HOBDI as a reference. The new compounds all exhibited significantly stronger fluorescence than p­HOBDI, up to 28 times higher quantum yields. An experimental and theoretical investigation of the relationship of the fluorescence properties with the molecular structure was also carried out. A good correlation was found between the emission wavenumber and the Hammett constant of the functional group, which suggests the intermolecular charge transfer (ICT) mechanism between the aromatic groups.


Assuntos
Corantes Fluorescentes/química , Proteínas de Fluorescência Verde/química , Imidazóis/química , Aminação , Técnicas de Química Combinatória , Fluorescência , Corantes Fluorescentes/síntese química , Imidazóis/síntese química , Modelos Moleculares , Espectrometria de Fluorescência
17.
J Pharm Biomed Anal ; 169: 260-268, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-30884324

RESUMO

An integrated chromatographic system was developed to rapidly investigate the biocatalytic properties of ω-transaminases useful for the synthesis of chiral amines. ATA-117, an (R)-selective ω-transaminase was selected as a proof of concept. The enzyme was purified and covalently immobilized on an epoxy monolithic silica support to create an immobilized enzyme reactor (IMER). Reactor efficiency was evaluated in the conversion of a model substrate. The IMER was coupled through a switching valve to an achiral analytical column for separation and quantitation of the transamination products. The best conditions of the transaminase-catalyzed bioconversion were optimized by a design of experiments (DoE) approach. The production of (R)-1-(4-methoxyphenyl)propan-2-amine and (R)-1-methyl-3-phenylpropylamine, intermediates for the synthesis of the bronchodilator formoterol and the antihypertensive dilevalol respectively, was achieved in the presence of different amino donors. The enantiomeric excess (ee) was determined off-line by developing a derivatization procedure using Nα-(2,4-dinitro-5-fluorophenyl)-L-alaninamide reagent. The most satisfactory conversion yields were 60% for (R)-1-(4-methoxyphenyl)propan-2-amine and 29% for (R)-1-methyl-3-phenylpropylamine, using isopropylamine as amino donor. The enantiomeric excess of the reactions were 84%R and 99%R, respectively.


Assuntos
Cromatografia/métodos , Enzimas Imobilizadas/química , Transaminases/química , Aminação/fisiologia , Aminas/química , Biocatálise , Catálise , Propilaminas/química , Estereoisomerismo
18.
J Food Prot ; 82(4): 696-702, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30917042

RESUMO

HIGHLIGHTS: A reductive amination-assisted method was used to synthesize standards and internal standards of ractopamine and salbutamol. Standard and internal standard analogs were fabricated by isotopic formaldehydes and sodium cyanoborohydride. A quantitative method of modified ractopamine and salbutamol was successfully validated. The reductive amination-assisted method enhances the signal for MS detection.


Assuntos
Agonistas Adrenérgicos beta/análise , Albuterol , Aminação , Fenetilaminas , Espectrometria de Massas em Tandem
19.
Org Lett ; 21(6): 1926-1929, 2019 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-30821980

RESUMO

Cu(II)-mediated direct NH2 and NH alkyl aryl aminations and olefin aziridinations are described. These room-temperature, one-pot, environmentally friendly procedures replace costly Rh2 catalysts and, in some instances, display important differences with comparable Rh2- and Fe-supported reactions.


Assuntos
Alcenos/química , Aziridinas/química , Cobre/química , Alcenos/síntese química , Aminação , Aziridinas/síntese química , Catálise , Estrutura Molecular
20.
Bioelectrochemistry ; 127: 163-170, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30831354

RESUMO

Long-term accumulation of organophosphate pesticides in environment presents a potential hazard to human and animal health. Towards this, a highly sensitive amperometric AChE-biosensor based on conjugated polymer and Ag-rGO-NH2 nanocomposite has been successfully developed. First, 4, 7-di (furan-2-yl) benzo thiadiazole (FBThF) was electrochemically polymerized on the electrode surface. Then, Ag-rGO-NH2 nanocomposite and acetylcholinesterase (AChE) are modified on the polymer membrane surface. In this way, a novel amperometric AChE-biosensor was successfully prepared. The as-prepared biosensor possessed excellent conductivity, catalytic activity, and biocompatibility which were attributed to the synergistic effects of poly(FBThF) and Ag-rGO-NH2 and provided a hydrophilic surface for AChE adhesion. Under optimized conductions, the linear range was 0.099-9.9 µg L-1 with a regression coefficient of 0.9947 for malathion, 0.0206-2.06 µg L-1 with a regression coefficient of 0.9969 for trichlorfon. The detection limit is calculated to be about 0.032 µg L-1 for malathion and 0.001 µg L-1 for trichlorfon (S/N = 3). Moreover, the biosensor exhibited acceptable reproducibility and long-term stability, which makes it possible to provide a novel and promising tool for analysis of organophosphate pesticides.


Assuntos
Acetilcolinesterase/química , Técnicas Biossensoriais/métodos , Grafite/química , Nanocompostos/química , Organofosfatos/análise , Praguicidas/análise , Prata/química , Aminação , Água Potável/análise , Enzimas Imobilizadas/química , Limite de Detecção , Malus/química , Oxirredução , Polímeros/química , Reprodutibilidade dos Testes , Poluentes Químicos da Água/análise
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