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1.
J Nanosci Nanotechnol ; 20(2): 828-839, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31383078

RESUMO

At present, high-performance cement-based composites are widely used, and they are prone to early cracking due to their high autogenous shrinkage stress. In this research, the uniformly dispersed GNPs were added into high-performance cementitious materials. The autogenous shrinkage of high-performance cementitious matrix materials with different incorporation of GNPs was also researched with water to cement ratio of 0.25, 0.30 and 0.35. According to hydration heat, hydration products, microstructure and porosity of GNPs cementitious matrix materials, the microcosmic mechanism for autogenous shrinkage was also investigated. It was testified that moderate addition of GNPs decreased the autogenous shrinkage of cement-based composites. Moreover, the autogenous shrinkage value was minimal after treatment with 0.10 wt% GNPs cement paste sample for 7 days, at the water to cement ratio of 0.35, and the depressed percentage of autogenous shrinkage reached 81.60% compared with the blank sample.

2.
J Nanosci Nanotechnol ; 20(1): 113-120, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31383145

RESUMO

Carbon nanofibers (CNFs) could not be distributed evenly in cement composites due to their high specific surface area and van der Waals force, and the poor dispersion of CNFs significantly influenced the performance of cement composites. Therefore, uniform dispersion of CNFs plays a significant role in the properties of cement composites. This study mainly investigated the cement composite samples with CNFs treated respectively by methyl cellulose (MC), sodium dodecyl sulfate (SDS) and MC+SDS. The UV-vis spectroscopy and optical microscopy results showed that the dispersion of CNFs in the MC+SDS solution was much better than that in MC and SDS solution. MC, SDS and MC+SDS solution improved the mechanical properties of CNFs reinforced cement composites, but the MC+SDS solution exhibited the greatest effect. Furthermore, the microstructure and morphology analysis indicated that uniform dispersed CNFs could accelerate the hydration process and phase formation, and improved the compactness and interfacial connection, so as to enhance the mechanical properties and microstructure of cement composites.

3.
Environ Int ; 132: 105051, 2019 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-31465953

RESUMO

This is one of a limited number of studies that investigates multimedia exposure to metal(loid)s and the related human health risks caused by atmospheric deposition in China and Asia. The aggregate multimedia human exposure included the accidental ingestion and dermal adsorption of soil and surface water, as well as the intake of grains, fruits, vegetables, meats and eggs, milk and dairy products, and freshwater fish. The values and variabilities of atmospheric deposition and exposure factors were identified as two major uncertainty sources. The annual variations in wet and bulk deposition were propagated from the variabilities of particulate matter (PM) × precipitation and the linear regressed coefficients of flux~PM × precipitation, and the annual variation in dry deposition was propagated by subtracting the wet deposition from the bulk deposition. The variabilities in the exposure factors were updated based on the latest published regional data. Long-term atmospheric deposition was identified as a vital source of Cd contamination in surface soil and freshwater bodies and As accumulation in freshwater fish. The noncarcinogenic (NC) risk probabilities caused by Cd were the highest, followed by As. The overall uncertainties related to the NC risk probabilities were much lower for both adults and 6- to 17-year-old children/adolescents, while those related to the carcinogenic risk (CR) probabilities were much lower for 2- to 5-year-old children and 6- to 17-year-old children/adolescents. Our results could help infer the cobenefits due to the current regional air pollution control policy.

4.
Pestic Biochem Physiol ; 157: 204-210, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31153470

RESUMO

Sulfoxaflor is the first commercially available sulfoximine insecticide, which exhibits highly efficacy against many sap-feeding insect pests and has been applied as an alternative insecticide against cotton aphid in China. This study was conducted to investigate the risk of resistance development, the cross-resistance pattern and the potential resistance mechanisms of sulfoxaflor in Aphis gossypii. A colony (SulR strain) of A. gossypii with 245-fold resistance, originated from Xinjiang field population, was established by continuous selection using sulfoxaflor. The SulR strain has developed cross-resistance to imidacloprid (80.8-fold), acetamiprid (19.3-fold), thiamethoxam (10.0-fold), and flupyradifurone (107.5-fold), while no cross-resistance was detected to malathion, omethoate, bifenthrin, methomyl, and carbosulfan. Piperonyl butoxide and S, S, S-tributyl phosphorotrithioate could significantly increase the toxicity of sulfoxaflor to the SulR strain by 5.99- and 4.18-fold, respectively, whereas no synergistic effect with diethyl maleate was observed. The activities of P450s and carboxylesterase were significantly higher in the SulR strain than that in the SS strain. Further gene expression determination demonstrated that nine P450 genes were significantly increased in SulR strain and suppression the expression of CYP6CY13 and CYP6CY19 by RNAi significantly increased the susceptibility of SulR adult aphids to sulfoxaflor. These results demonstrated that the enhancing detoxification by cytochrome P450 monooxygenase may be involved in A.gossypii resistance to sulfoxaflor.


Assuntos
Afídeos/efeitos dos fármacos , Sistema Enzimático do Citocromo P-450/metabolismo , Piridinas/farmacologia , Compostos de Enxofre/farmacologia , 4-Butirolactona/análogos & derivados , 4-Butirolactona/farmacologia , Animais , Afídeos/genética , Afídeos/metabolismo , Sistema Enzimático do Citocromo P-450/genética , Resistência a Inseticidas/genética , Inseticidas/farmacologia , Neonicotinoides/farmacologia , Nitrocompostos/farmacologia , Piretrinas/farmacologia
5.
Drug Test Anal ; 2019 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-31150570

RESUMO

Dihydroartemisinin (DHA) and piperaquine (PPQ) are two drugs used in an artemisinin-based combination therapy (ACT). The circulation of counterfeit antimalarial drugs demands the development of simple, point-of-care (POC) tests for monitoring drug quality. Here we aimed to design an antibody-based lateral flow dipstick assay for simultaneous quality control of DHA and PPQ. To obtain a monoclonal antibody (mAb) for PPQ, one structural unit of the symmetric PPQ molecule was used to derive a carboxylic acid for linkage to a carrier protein as immunogen. Screening of hybridoma cells identified an mAb 4D112B2 that reacted with the PPQ-based immunogen. A highly-sensitive icELISA was designed based on this mAb, which showed 50% inhibition concentration of PPQ at 1.66 ng/mL and a working range of 0.35 - 7.40 ng/mL. The mAb showed 10.2, 15.9 and 30.4% cross reactivity to hydroxychloroquine sulfate, chloroquine and amodiaquine, respectively. No cross reactivity was observed to lumefantrine, mefloquine artemisinin and its derivatives. Using our previous DHA dipstick design, a lateral flow dipstick for simultaneous analysis of PPQ and DHA was developed. The indicator ranges for PPQ and DHA were 2 - 5 µg/mL and 250 - 500 ng/mL, respectively. The dipstick was used to semi-quantitatively analyze PPQ and DHA content in commercial ACT drugs, which produced agreeable results to those determined by high-performance liquid chromatography. This combination dipstick makes it a potential POC device for quality control of the two active ingredients in a commonly used ACT.

6.
Food Chem ; 293: 144-150, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31151594

RESUMO

Nobiletin, a polymethoxyflavone mainly found in citrus fruits, have been reported to exhibit various beneficial biological activities for human health. It is an important bioactive compound in traditional Chinese medicine, Pericarpium Citri Reticulatae and Fructus Aurantii. To detect the contents of nobiletin in citrus and herb samples, we developed an indirect competitive enzyme-linked immunosorbent assay (icELISA) based on monoclonal antibodies. It possessed a median inhibition concentration (IC50) of 2.43 ±â€¯0.19 ng/mL and a working range of 0.52-12.3 ng/mL. The assay exhibited the average recoveries of 72.5-85.3% in citrus peel, pulp and juice samples. Moreover, eleven citrus cultivars samples and four herb samples were also detected by the icELISA. The nobiletin content varied in different citrus cultivars samples and herb samples, which were confirmed by the ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS). These results indicated that the developed immunoassay was suitable for detecting nobiletin in citrus and herb samples.


Assuntos
Citrus/química , Flavonas/análise , Anticorpos Monoclonais/imunologia , Citrus/metabolismo , Ensaio de Imunoadsorção Enzimática , Flavonas/química , Flavonas/imunologia , Frutas/química , Frutas/metabolismo , Sucos de Frutas e Vegetais/análise , Haptenos/química , Haptenos/imunologia , Medicina Tradicional Chinesa
7.
J Org Chem ; 84(12): 8300-8308, 2019 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-31132277

RESUMO

A chiral phosphoric acid-catalyzed enantioselective synthesis of fluorinated 5,6-dihydroindolo[1,2- c]quinazolines has been developed by a condensation/amine addition cascade from 2-(1 H-indolyl)anilines and fluorinated ketones, giving the fluorinated aminals with quaternary stereogenic centers with excellent yields and up to 97% ee. A series of the fluorinated aromatic, aliphatic ketones, and ethyl trifluoropyruvate are suitable.

8.
Food Chem ; 291: 132-138, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31006451

RESUMO

trans-Resveratrol, a natural polyphenol present in grapes, has many beneficial effects to human health. However, measurement of trans-resveratrol is technically complicated and time-consuming. In the present study, we obtained a sensitive and specific monoclonal antibody (mAb), namely 3C9, against trans-resveratrol. An indirect competitive enzyme-linked immunosorbent assay (icELISA) was developed, with 50% inhibitory concentration and working range of 1.0 ng/mL and 0.19-4.9 ng/mL, respectively. A lateral flow immunoassay (LFIA) based on 3C9 was also developed for the semiquantitative detection of trans-resveratrol in an indicator range of 50-100 ng/mL. Average recoveries of trans-resveratrol spiked in red and green grape berries samples were respectively 88-107% and 83-102% by icELISA. The icELISA and LFIA were applied for determination of trans-resveratrol in grape berries. The results were highly consistent with those determined by high-performance liquid chromatography analysis (R2 = 0.9997). Therefore, we conclude that the immunoassay methods are suitable for the large-scale screening of trans-resveratrol in grape quality breeding.


Assuntos
Ensaio de Imunoadsorção Enzimática , Resveratrol/análise , Vitis/química , Animais , Anticorpos Monoclonais/imunologia , Cromatografia Líquida de Alta Pressão , Feminino , Frutas/química , Frutas/metabolismo , Isomerismo , Camundongos , Camundongos Endogâmicos BALB C , Resveratrol/imunologia , Vitis/metabolismo
9.
J Pharm Biomed Anal ; 170: 83-88, 2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-30909057

RESUMO

Flos Lonicerae Japonicae (FLJ), known as golden-and-silver honeysuckle, is a widely used Chinese herbal medicine with pharmacological activities and edibleness in China. Chlorogenic acid (CGA) and luteoloside are the quality control markers of FLJ regulated by the Chinese Pharmacopoeia (2015 edition). For rapid evaluation of the quality of FLJ, dipsticks for CGA and luteoloside detection were developed. The detection limit of the dipsticks for CGA and luteoloside, defined as the lowest concentration of the target analyte between which the test line was invisible, were 100 ng/mL and 200 ng/mL, respectively. The dipsticks were used for determination of CGA and luteoloside contents in FLJ, and the results were confirmed by high-performance liquid chromatography. The developed dipsticks, with their simplicity of use, lack of dependence on instruments and environmental friendliness, could be used to evaluate the quality of FLJ within 10 min.


Assuntos
Ácido Clorogênico/química , Glucosídeos/química , Coloide de Ouro/química , Imunoensaio/métodos , Lonicera/química , Luteolina/química , Extratos Vegetais/química , China , Cromatografia Líquida de Alta Pressão/métodos , Medicamentos de Ervas Chinesas/química , Flores/química , Controle de Qualidade
10.
Sci Rep ; 9(1): 2131, 2019 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-30765780

RESUMO

Flubendiamide (FD), the first commercial phthalic acid diamide that targets insect ryanodine receptor (RyRs), has played an important role in pest management. With its extensive worldwide application, a rapid and convenient method to detect its existence in the environment is necessary. In this study, an indirect competitive enzyme-linked immunosorbent assay (icELISA) was developed to analyse FD residue on environmental and food samples. The established icELISA showed a half maximal inhibition concentration (IC50) of 17.25 µg L-1, with a working range of 4.06-103.59 µg L-1 for FD, and showed no cross-reactivity with chlorantraniliprole, cyantraniliprole, and several FD analogues. Average FD recoveries from spinach, tap water, and soil samples were 89.3-112.3%, 93.0-102.1%, and 86.9-97.6%, respectively. Meanwhile, FD detection results of icELISA were compared with those of ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The comparable results verified that icELISA was suitable for rapid detection of FD residue in environmental and agricultural samples.

11.
Nano Lett ; 19(2): 787-792, 2019 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-30626186

RESUMO

Plastic optics are used in an ever-expanding range of applications and yet a durable, high performance antireflection (AR) coating remains elusive for this material class. Here, we introduce a sacrificial porogen approach to produce ultralow refractive index nanoporous fluoropolymer AR coatings via thermal coevaporation of Teflon AF and the small molecule N, N'-bis(3-methylphenyl)- N, N'-diphenylbenzidine (NPD). Using this approach, we demonstrate a five-layer, step-graded AR coating that reduces the solar spectrum-averaged (400 < λ < 2000 nm) reflectance of acrylic plastic to <0.5% for incidence angles up to 40° and withstands over 3 months of outdoor rooftop exposure with minimal degradation. A trilayer coating optimized for the visible range yields luminous reflectivity down to ∼0.1%, effectively rendering double-side coated acrylic plastic invisible under room lighting conditions. Strong adhesion to most optical plastics, an outstanding combination of mechanical, chemical, and environmental durability, and compatibility with commercial vacuum coating systems should enable this AR technology to find widespread practical use.

12.
BMC Plant Biol ; 18(1): 361, 2018 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-30563457

RESUMO

BACKGROUND: Mepiquat chloride (MC) is a plant growth regulator widely used in cotton (Gossypium hirsutum L.) production to suppress excessive vegetative growth, increase root growth and avoid yield losses. To increase root growth, cotton seeds were treated with MC to increase the number of lateral root (LRs) and improve drought resistance. An increased indole-3-acetic acid (IAA) pool appeared to correlate with LR growth, and the principal source of IAA in germinating seeds is IAA conjugates. Here, the role of IAA homeostasis and signaling was investigated in cotton seedlings treated with MC. RESULTS: In the present research, MC significantly increased endogenous IAA levels in the roots, which promoted lateral root initiation (LRI) by upregulating GhARF7/19 and GhLBD18s and subsequently increasing LR quantity and elongation. The levels of IAA-amide conjugates significantly decreased in MC-treated seedlings compared with untreated control seedlings. Sixteen members of the cotton IAA amidohydrolase (IAH) gene family were identified, of which GhIAR3a, GhIAR3b, GhILR1, GhILL3 and GhILL6 were expressed during cotton seed germination. Compared with those in untreated control seedlings, the expression levels of GhIAR3a, GhIAR3b, GhILR1 and GhILL6 in the MC-treated seedlings were markedly elevated. The GhIAR3a/b and GhILR1 genes were cloned and expressed in Escherichia coli; these recombinant proteins exhibited hydrolytic activity that could cleave IAA-phenyalanine (Phe), IAA-methionine (Met), IAA-glycine (Gly) and IAA-leucine (Leu) in vitro, while only GhIAR3a hydrolyzed IAA-alanine (Ala) efficiently. The content of GhIAR3a, as detected via an established sandwich enzyme-linked immunosorbent assay (ELISA), increased in the MC-treated seedlings compared with the untreated control seedlings. In addition, the Arabidopsis iar3 mutant was less responsive to MC-induced LR growth than was wild type. CONCLUSIONS: These findings suggested that MC application could mediate IAA homeostasis via increased IAA levels from IAA-amide conjugate hydrolysis by accelerating IAH gene expression, which might promote LRI and increase the LR quantity and elongation.


Assuntos
Gossypium/efeitos dos fármacos , Ácidos Indolacéticos/metabolismo , Piperidinas/farmacologia , Reguladores de Crescimento de Planta/farmacologia , Raízes de Plantas/efeitos dos fármacos , Amidoidrolases/genética , Animais , Anticorpos Monoclonais , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Clonagem Molecular , Ensaio de Imunoadsorção Enzimática/métodos , Regulação da Expressão Gênica de Plantas , Gossypium/genética , Gossypium/crescimento & desenvolvimento , Gossypium/metabolismo , Homeostase/efeitos dos fármacos , Camundongos , Mutação , Proteínas de Plantas/genética , Proteínas de Plantas/imunologia , Proteínas de Plantas/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento
13.
Chem Commun (Camb) ; 54(93): 13119-13122, 2018 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-30398494

RESUMO

Reduction of a thiolate-bridged FeIIFeIII complex leads to the cleavage of an Fe-S bond by the insertion of the methylene unit from CH2Cl2 to give a neutral FeIIFeIII complex with a novel Fe-CH2-S fragment. The structural and electrochemical differences of the alkylated and the non-alkylated Fe2S2 complexes are also examined.

14.
Inorg Chem ; 2018 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-30485081

RESUMO

In the presence of 1 equiv of tBuNC, the homolytic cleavage of the FeIII-H bond in the diiron terminal hydride complex [Cp*Fe( t-H)(µ-η2:η4-bdt)FeCp*][BF4] (1[BF4]) smoothly took place to release 1/2 H2, followed by binding of a tBuNC group to the unsaturated FeII center. Interestingly, upon exposure of 1[BF4] to 1 atm of acetylene, the isomerization process of the hydride ligand from the terminal to bridging coordination site was unaffected. Upon treatment of the diiron hydride bridged complex 2[BF4] with acetylene at 30 °C, two FeIII-H bonds were broken, and then an acetylene molecule was coordinated to the diiron centers in a novel µ-η2:η2 side-on fashion. In the above reaction system, the hydride ligands whether terminal or bridging all play a role as the electron donor for the reduction of the diiron centers from FeIIIFeIII to FeIIIFeII. These reaction patterns are reminiscent of the vital E4 state responsible for N2 binding and H2 liberation in the catalytic cycle of nitrogenase, which contains two {Fe-H-Fe} motifs as electron reservoirs for the reduction of the iron centers. Differently, when treating 1[BF4] with TMSN3, the terminal hydride ligand was inserted into the azide group to give a diiron amide complex 4[BF4] in moderate yield.

15.
Cancers (Basel) ; 10(9)2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-30200436

RESUMO

The tumor suppressor and transcription factor p53 plays critical roles in tumor prevention by orchestrating a wide variety of cellular responses, including damaged cell apoptosis, maintenance of genomic stability, inhibition of angiogenesis, and regulation of cell metabolism and tumor microenvironment. TP53 is one of the most commonly deregulated genes in cancer. The p53-ARF-MDM2 pathway is deregulated in 84% of glioblastoma (GBM) patients and 94% of GBM cell lines. Deregulated p53 pathway components have been implicated in GBM cell invasion, migration, proliferation, evasion of apoptosis, and cancer cell stemness. These pathway components are also regulated by various microRNAs and long non-coding RNAs. TP53 mutations in GBM are mostly point mutations that lead to a high expression of a gain of function (GOF) oncogenic variants of the p53 protein. These relatively understudied GOF p53 mutants promote GBM malignancy, possibly by acting as transcription factors on a set of genes other than those regulated by wild type p53. Their expression correlates with worse prognosis, highlighting their potential importance as markers and targets for GBM therapy. Understanding mutant p53 functions led to the development of novel approaches to restore p53 activity or promote mutant p53 degradation for future GBM therapies.

16.
Clin Cancer Res ; 2018 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-30201763

RESUMO

Purpose: Glioblastoma (GBM) is the most common and most lethal primary malignant brain tumor. The receptor tyrosine kinase MET is frequently upregulated or overactivated in GBM. Although clinically applicable MET inhibitors have been developed, resistance to single modality anti-MET drugs frequently occurs, rendering these agents ineffective. We aimed to determine the mechanisms of MET inhibitor resistance in GBM and use the acquired information to develop novel therapeutic approaches to overcome resistance.Experimental Design: We investigated two clinically applicable MET inhibitors: crizotinib, an ATP-competitive small molecule inhibitor of MET, and onartuzumab, a monovalent monoclonal antibody that binds to the extracellular domain of the MET receptor. We developed new MET inhibitor-resistant cells lines and animal models and used reverse phase protein arrays (RPPA) and functional assays to uncover the compensatory pathways in MET inhibitor-resistant GBM.Results: We identified critical proteins that were altered in MET inhibitor-resistant GBM including mTOR, FGFR1, EGFR, STAT3, and COX-2. Simultaneous inhibition of MET and one of these upregulated proteins led to increased cell death and inhibition of cell proliferation in resistant cells compared with either agent alone. In addition, in vivo treatment of mice bearing MET-resistant orthotopic xenografts with COX-2 or FGFR pharmacological inhibitors in combination with MET inhibitor restored sensitivity to MET inhibition and significantly inhibited tumor growth.Conclusions: These data uncover the molecular basis of adaptive resistance to MET inhibitors and identify new FDA-approved multidrug therapeutic combinations that can overcome resistance. Clin Cancer Res; 1-11. ©2018 AACR.

17.
Chem Commun (Camb) ; 54(82): 11515-11529, 2018 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-30225504

RESUMO

As a powerful synthon, pyrazolone has widely been exploited for the construction of various chiral pyrazoles/pyrazolones which hold great potential in the development of pharmaceutical chemistry, coordination chemistry and functional materials. Benefited from the diversity and multiple active sites of the starting materials, such as 4-nonsubstituted/4-monosubstituted pyrazolones and α,ß-unsaturated pyrazolones, large numbers of strategies for the asymmetric synthesis of various pyrazoles/pyrazolones have been developed successfully in the past few years. This feature article summarizes these excellent research studies since 2015, including some efforts by our group. Based on the structural feature of the final products, this feature article is divided into four sections, including the catalytic asymmetric synthesis of 4-monosubstituted, 4-disubstituted, fused and spiro pyrazoles/pyrazolones. Schematic illustrations are given for some representative examples in each section.

18.
J Nanosci Nanotechnol ; 18(12): 8186-8194, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30189936

RESUMO

Multi-walled carbon nanotubes (MWCNTs) modified by gum arabic (GA) were incorporated into cement matrix composites to investigate their effect on intrinsic properties. Their ability to disperse the surface-modified MWCNTs uniformly in the cement matrix was also assessed using transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). The intrinsic mechanical properties of the cement composites were investigated using Nano Indenter. Results showed that the addition of treated nanotubes significantly improved the intrinsic properties of cement matrix composites. The porosity and pore size distribution of the composites were measured using mercury intrusion porosimetry (MIP), and the results indicated that cement paste containing MWCNTs had lower porosity and a more uniform pore size distribution. The morphological structure of samples was investigated using field emission scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and X ray diffraction analysis (XRD), which showed that the MWCNTs acted as bridges across cracks and voided and formed a network that transferred the load in tension.

19.
Org Biomol Chem ; 16(34): 6275-6283, 2018 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-30116825

RESUMO

An iodine-mediated alkenylation of pyrazolones with simple alkenes under an air atmosphere has been developed. By this protocol, the pharmaceutically relevant pyrazolone scaffold was directly adorned with a readily transformable olefinic functional group through a cross-dehydrogenative coupling process in moderate to excellent yields. The coupling products could be facilely manipulated by, for example, the Heck reaction and hydrogenation treatment, thus enriching the pyrazolone derivatives. Based on the observation of the reaction intermediate and mechanistical experiments, two possible reaction pathways were proposed.

20.
Chem Commun (Camb) ; 54(79): 11112-11115, 2018 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-30155542

RESUMO

Thiolate-bridged dirhodium and diiridium complexes can facilely realize heterolytic cleavage of H2 across the metal-sulfur bond to generate the corresponding hydride bridged complexes. Furthermore, terminal alkynes can insert the Rh-H-Rh fragment to afford σ:π alkenyl bridged complexes and then convert to the corresponding alkenes in the presence of a reductant and an acid.

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