1121-60-4Relevant articles and documents
Solution Dynamics of Hybrid Anderson-Evans Polyoxometalates
Salazar Marcano, David E.,Lentink, Sarah,Moussawi, Mhamad A.,Parac-Vogt, Tatjana N.
, p. 10215 - 10226 (2021)
Understanding the stability and speciation of metal-oxo clusters in solution is essential for many of their applications in different areas. In particular, hybrid organic-inorganic polyoxometalates (HPOMs) have been attracting increasing attention as they combine the complementary properties of organic ligands and metal-oxygen nanoclusters. Nevertheless, the speciation and solution behavior of HPOMs have been scarcely investigated. Hence, in this work, a series of HPOMs based on the archetypical Anderson-Evans structure, δ-[MnMo6O18{(OCH2)3C-R}2]3-, with different functional groups (R = -NH2, -CH3, -NHCOCH2Cl, -NCH(2-C5H4N) {pyridine; -Pyr}, and -NHCOC9H15N2OS {biotin; -Biot}) and countercations (tetrabutylammonium {TBA}, Li, Na, and K) were synthesized, and their solution behavior was studied in detail. In aqueous solutions, decomposition of HPOMs into the free organic ligand, [MoO4]2-, and free Mn3+ was observed over time and was shown to be highly dependent on the pH, temperature, and nature of the ligand functional group but largely independent of ionic strength or the nature of the countercation. Furthermore, hydrolysis of the amide and imine bonds often present in postfunctionalized HPOMs was also observed. Hence, HPOMs were shown to exhibit highly dynamic behavior in solution, which needs to be carefully considered when designing HPOMs, particularly for biological applications.
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Papadopoulos et al.
, p. 615 (1966)
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Newkome et al.
, p. 410 (1974)
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Copper-catalyzed selective oxygenation of methyl and benzyl substituents in pyridine with O2
Abe, Tsukasa,Tanaka, Shinji,Ogawa, Atsuko,Tamura, Masanori,Sato, Kazuhiko,Itoh, Shinobu
, p. 348 - 350 (2017)
A selective oxygenation of picolines and their derivatives has been achieved by usingasimple copper salt as a catalyst and molecular oxygen as an oxidant, where the α-position of the alkyl substituent is selectively oxidized to give the corresponding aldehydes or ketones. Addition of a catalytic amount of water enhances the catalytic activity, which could be attributed to the role of the proton donor to activate the substrates.
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Lejtis,Simanskaja
, (1969)
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Improving the reactivity of hydrazine-bearing MRI probes for: In vivo imaging of lung fibrogenesis
Akam, Eman A.,Abston, Eric,Rotile, Nicholas J.,Slattery, Hannah R.,Zhou, Iris Y.,Lanuti, Michael,Caravan, Peter
, p. 224 - 231 (2020)
Pulmonary fibrosis (PF) is the pathologic accumulation of extracellular matrix components in lung tissue that result in scarring following chronic lung injury. PF is typically diagnosed by high resolution computed tomography (HRCT) and/or invasive biopsy. However, HRCT cannot distinguish old injury from active fibrogenesis. We previously demonstrated that allysine residues on oxidized collagen represent an abundant target during lung fibrogenesis, and that magnetic resonance imaging (MRI) with a small-molecule, gadolinium-containing probe, Gd-Hyd, could specifically detect and stage fibrogenesis in a mouse model. In this work, we present an improved probe, Gd-CHyd, featuring an N,N-dialkyl hydrazine which has an order of magnitude both greater reactivity and affinity for aldehydes. In a paired study in mice with bleomycin induced lung injury we show that the improved reactivity and affinity of Gd-CHyd results in significantly higher lung-to-liver contrast, e.g. 77% higher at 45 min post injection, and slower lung clearance than Gd-Hyd. Gd-CHyd enhanced MRI is >60-fold higher in bleomycin injured mouse lungs compared to uninjured mice. Collectively, our data indicate that enhancing hydrazine reactivity and affinity towards allysine is an effective strategy to significantly improve molecular MRI probes for lung fibrogenesis.
The Synergy Effect in Tio2 Supported Bi-Mo Catalysts for Facile and Environmentally-Friendly Synthesis of Pyridylaldehydes from Oxidation of Picolines
Dai, Liyan,Jie, Yu,Zhylko, Viachaslau
, p. 181 - 186 (2020)
Abstract: The oxidation of picolines to pyridlaldehydes was studied over bismuth molybdate catalysts supported on TiO2. The research results showed that α-Bi2Mo3O12 was superior to β-Bi2Mo2O9 and γ-Bi2MoO6 in terms of reactivity. Further doping MoO3 to α-Bi2Mo3O12/TiO2 gave rise to increased catalytic performance, which was due to the synergy effect of α-Bi2Mo3O12 and MoO3. The effect was on one hand manifested in the intimate relationship between α-Bi2Mo3O12 and MoO3 in stabilizing the crystallographic structure of catalysts and thereafter maintaining the surface area of the catalyst, as indicated by the BET surface area and XRD analysis. Moreover, NH3-TPD analysis demonstrated the effect in modifying the surface acidity of the catalysts, and thus facilitating the substrate adsorption as the picolines are alkaline substances. Additionally, the effect between α-Bi2Mo3O12 and MoO3 rendered the modification of the electronic properties and thereafter the oxygen desorption properties and reducible properties of the catalysts, as evidenced in the H2-TPR and O2-TPD analysis.
An Optical Resolution of Pyridyl and Bipyridylethanols and A Facile Preparation of Optically Pure Oligopyridines
Uenishi, Jun'ichi,Nishiwaki, Kenji,Hata, Shinichiro,Nakamura, Kaoru
, p. 7973 - 7976 (1994)
A kinetic resolution of racemic pyridyl and bipyridylethanols was performed by Candida antarctica lipase with vinyl acetate in diisopropyl ether, in which (R)-alcohol was acetylated stereoselectively, and both the acetate 2 and the remaining (S)-alcohol 1 were obtained with high enantiomeric excesses. (S)-Oligopyridylethanols, 7 and 8 were prepared by a coupling reaction of (S)-1b and (S)-1e with ethyl bipyridyl sulfoxide.
Hydroxyl radical-mediated oxidative cleavage of CC bonds and further esterification reaction by heterogeneous semiconductor photocatalysis
Hong, Mei,Jia, Rui,Miao, Hongyan,Ni, Bangqing,Niu, Tengfei,Wang, Hui
, p. 6591 - 6597 (2021/09/10)
A hydroxyl radical-mediated aerobic cleavage of alkenes and further sequence esterification reaction for the preparation of carbonyl compounds have been developed by using tubular carbon nitride (TCN) as a general heterogeneous photocatalyst under an oxygen atmosphere with visible light irradiation. This protocol has an excellent substrate scope and gives the desired aldehydes, ketones and esters in moderate to high yields. Importantly, this metal-free procedure employed photogenerated hydroxyl radicals in situ as green oxidation active species, avoiding the present additional initiators. The reaction could be carried out under solar light irradiation and was applicable to large-scale reactions. Furthermore, the recyclable TCN catalyst could be used several times without a significant loss of activities.
Aryl aldiketone and synthesis method thereof
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Paragraph 0020, (2021/09/26)
The invention discloses an aryl aldehyde ketone and a synthesis method thereof, wherein an aryl aldehyde is synthesized from cheap olefin as a raw material. A commercially available inexpensive olefin is used as a raw material, ether is used as an additive, molecular oxygen serves as a sole oxidizing agent, water is used as a solvent, and the aldehyde and ketone are synthesized by column chromatography under a photocatalytic condition. The invention has the advantages of mild reaction conditions, green and environmental protection, simple experimental operation, good reaction selectivity, high product yield and the like.
Efficient synthesis of acrylates bearing an aryl or heteroaryl moiety: One-pot method from aromatics and heteroaromatics using formylation and the horner-wadsworth-emmons reaction
Yasukata, Tatsuro,Matsuura, Takaharu
, p. 527 - 533 (2021/03/22)
Acrylates bearing an aryl or heteroaryl moiety were efficiently prepared by a one-pot process employing a sequence of lithiation, formylation and the Horner-Wadsworth-Emmons reaction starting from aromatic and heteroaromatic compounds. This method can efficiently introduce an acrylate moiety into aromatic and heteroaromatic compounds.
