Palladium nanoparticles in cross-linked polyaniline as highly efficient catalysts for Suzuki-Miyaura reactions

Palladium nanoparticles supported on cross-linked polyaniline with bulky phosphorus ligands were developed.These catalysts showed high efficiency in the Suzuki-Miyaura reaction of aryl chlorides and bromides with phenylboronic acids.Aryl chlorides and bromides with functional groups,such as CN,MeO,CHO,MeCO and NO_2,were converted to the corresponding biphenyls in high yields with catalyst loading.Additionally,the catalysts combined high activity with good reusability;they could be used at least five times for the Suzuki-Miyaura coupling reaction.

Lipopolysaccharide preconditioning induces protection against lipopolysac-charide -induced neurotoxicity in organotypic midbrain slice culture

Objective To identify the protective effect of lipopolysaccharide （LPS） preconditioning against LPS-induced inflammatory damage in dopaminergic neurons of midbrain slice culture and the possible mechanisms. Methods After cultured in vitro for 14 d, the rat organotypic midbrain slices were pretreated with different concentrations （0, 1, 3, 6 or 10 ng/mL） of LPS for 24 h followed by treatment with 100 ng/mL LPS for 72 h. The whole slice viability was detelmined by measurement of the activity of lactic acid dehydrogenase （LDH）. Tyrosine hydroxylase-immunoreactive （TH-IR） neurons and CD 1 1 b/c equivalent-immunoreactive （OX-42-IR） microglia in the slices were observed by immunohistochemical method, and tumor necrosis factor-α （TNF-α levels in the culture media were detected by enzymelinked immunosorbent assays （ELISA）. Results In the slices treated with 100 ng/mL LPS for 72 h, the number of TH-IR neurons reduced from 191± 12 in the control slices to 46±4, and the LDH activity elevated obviously （P 〈 0.01）, along with remarkably increased number of OX-42-IR cells and production of TNF-α （P 〈 0.01）. Preconditioning with 3 or 6 ng/mL LPS attenuated neuron loss （the number of TH-IR neurons increased to 126± 12 and 180± 13, respectively） and markedly reduced LDH levels （P 〈 0.05）, accompanied by significant decreases of OX-42-IR microglia activation and TNF-α production （P 〈 0.05）. Conclusion Low-dose LPS preconditioning could protect dopaminergic neurons against inflammatory damage in rat midbrain slice culture, and inhibition of microglial activation and reduction of the proinflammatory factor TNF-α production may contribute to this protective effect. Further understanding the underlying mechanism of LPS preconditioning may open a new window for treatment of Parkinson＇s disease.

Recent advances in fixation of CO_(2) into organic carbamates through multicomponent reaction strategies

Carbon dioxide(CO_(2)) is the main greenhouse gas and also an ideal C1 feedstock in organic synthesis because it is abundant,nontoxic,nonflammable,and renewable.The synthesis of organic carbamates using CO_(2) as a phosgene alternative has attracted extensive attention because of the importance of carbamates in organic synthesis and in the pharmaceutical and agrochemical industries.In recent decades,many multicomponent reaction strategies have been designed for constructing different types of organic carbamate molecules.Most of these methods rely on the in situ generation of carbamate anions from CO_(2) and amines,followed by reactions with other coupling partners.Synthetic strategies for acyclic carbamates include nucleophile‐electrophile coupling,nucleo‐phile‐nucleophile oxidative coupling,difunctionalization of unsaturated hydrocarbons,and C–H bond functionalization.Strategies for the synthesizing cyclic carbamates include carboxylative cyclization of in situ‐generated unsaturated amines and difunctionalization of unsaturated amines with CO_(2) and other electrophilic reagents.This review summarizes the recent advances in the synthesis of organic carbamates from CO_(2) using different multicomponent reaction strategies.Future perspectives and challenges in the incorporation of CO_(2) into carbamates are also presented.

多亚甲基多苯基多胺制造过程的优化

多亚甲基多苯基多胺是多苯基甲烷多异氰酸脂 (MDI)的中间体。MDI由于其良好的性能和广泛的用途 ,近几年发展迅速 ,多亚甲基多苯基多胺的制造是MDI制造过程的关键。通过对大量实验数据进行分析 ,根据多亚甲基多苯基多胺反应过程的反应机理 ,导出了产品多胺含量的影响因素 ,建立了多胺反应的数学模型 。

Versatile inorganic-organic hybrid WOx-ethylenediamine nanowires： Synthesis, mechanism and application in heavy metal ion adsorption and catalysis

Inorganic-organic hybrid WOx-ethylenediamine （WO/-EDA） nanowires have been produced by a simple, low-cost and high-yield solvothermal method. These WO/-EDA hybrid nanowires have unique lamellar mesostructures with an alternate stacking of an interconnected [WO6] octahedral layer and a monolayer of ethylenediamine molecules. This hybrid structure integrated the functionality of ethylenediamine with the stability of the WOx frameworks. In situ synchrotron- radiation X-ray diffraction is used to elucidate a possible formation mechanism of the hybrid WOx-EDA. The nanowire morphology, lamellar structure and abundant functional amino groups endow them with versatile abilities. For example, in heavy metal ion adsorption the WOx-EDA nanowires display exceptional adsorption capabilities of 925 mg·g^-1 for Pb^2＋ and 610 mg·g^-1 for UO2^2＋. The nanowires also show outstanding stability and activity as a heterogeneous base catalyst in the Knoevenagel condensation reaction at room temperature. The catalyst can be recycled and reused for 20 cycles with nearly 100% yields. This study provides a new strategy to design inorganic-organic hybrid materials, and offers a multifunctional material that is a highly efficient adsorbent and sustainable catalyst.

Polydopamine directed MnO@C microstructures as electrode for lithium ion battery

In this work,a facile process was reported to fabricate amorphous carbon-coated MnO micropeanuts(MPs)with 1.8μm in length and 1.0μm in width using hydrothermal reaction followed by heat treatment in the oxygen-free environment.With Mn Cl_2 and KMnO_4 dissolved in the mixture of ethylene glycol and water,MnCO_3 MP precursors were obtained via the hydrothermal reaction with dopamine as surfactant.Then MnCO_3 MP was annealed at 600°C in the N_2 atmosphere and was transformed into MnO MP,and simultaneously the formed polydopamine during the hydrothermal reaction was carbonized to produce amorphous carbon-coating on the MnO MP surface.In contrast,MnCO_3 nanoparticle(NP)precursor was formed without the addition of dopamine and MnO NP agglomerates were prepared after pyrolysis.The carbonization of polydopamine during thermolysis improves the electrical conductivity and thermal stability of the MnO MP and thus its electrochemical performance as electrode materials for lithium ion battery.Hopefully,this facile strategy for fabricating and designing carbon-coated materials would inspire more novel nanostructures and applications thereof.

Novel ractopamine–protein carrier conjugation and its application to the lateral flow strip test for ractopamine detection in animal feed

In this work,a novel conjugate of ractopamine and bovine serum albumin(RAC–BSA)has been developed via the Mannich reaction,with a mole coupling ratio for RAC–BSA of 9:1.The proposed conjugation method provides a simple and one-step method with the use of fewer reagents compared with other conjugation methods for competitive immunoassays.RAC–BSA conjugation was used to fabricate a competitive lateral flow strip test for RAC detection in animal feed.For sample preparation,RAC was spiked in swine feed purchased from the local markets in Thailand,and methanol and running buffer at a volume ratio of 10:90 was used as extraction buffer.The procedures for sample preparation were completed within 25 min.Under optimal conditions,the limit of detection(LOD),assessed by the naked eye within 5 min,was found to be 1 ng/g.A semi-quantitative analysis was also conducted using a smart phone and computer software,with a linearity of 0.075–0.750 ng/g,calculated LOD of 0.10 ng/g,calculated limit of quantitation of 0.33 ng/g,and good correlation of 0.992.The recoveries were found in the range of 96.4%–103.7%with a relative standard deviation of 2.5%–3.6%for intra-and inter-assays.Comparison of the results obtained by the strip test with those obtained by enzyme-linked immunosorbent assay had a good agreement in terms of accuracy.Furthermore,this strip test exhibited highly specific RAC detection without cross reactivity with related compounds.Therefore,the RAC–BSA conjugation via the Mannich reaction can be accepted as a one-step and easy conjugation method and applied to the competitive lateral flow strip test.