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Lithium Acetate (lithium + acetate)
Selected AbstractsSynthesis and characterization of fine lithium niobate powders by sol- gel methodCRYSTAL RESEARCH AND TECHNOLOGY, Issue 4 2007L. H. Wang Abstract Lithium niobate (LN) nanocrystal powders were prepared by low-temperature sol-gel method. Dihydrate lithium acetate as lithium source, and niobium chloride as niobium source were used as starting materials. The gel and powders were characterized by thermogravimetry and differential scanning calorimetry (TG/DSC), X-ray diffraction (XRD), transmission electronmicroscopy (TEM) and Fourier transform infrared (FTIR) spectra. The results show that when the gel was heat-treated at 600°C, the fine LN nanocrystals with the size of 40-60 nm were obtained, and the size of the powders become larger with the heat-treated temperature increasing. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Palladium-Catalyzed Asymmetric Allylic Alkylation of 2,3-Allenyl Acetates Using a Chiral Diaminophosphine OxideADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Tetsuhiro Nemoto Abstract An enantioselective synthesis of allenes through palladium-catalyzed asymmetric allylic alkylation using a chiral diaminophosphine oxide is described. The asymmetric allylic alkylations proceeded in the presence of a catalytic amount of lithium acetate at 4,°C, affording the chiral allenes in excellent yield with up to 99% ee. [source] Poster Sessions AP13: Novel Techniques and TechnologiesJOURNAL OF NEUROCHEMISTRY, Issue 2002J. K. Yao Studies of the antioxidant defense system and the monoamine metabolic pathways are often complicated by cumbersome analytical methods, which require separate and multistep extraction and chemical reaction procedures. Thus, measurements of multiple parameters are limited in relatively small biological samples. High performance liquid chromatography (HPLC) coupled with a Coulometric Multi-Electrode Array System (CMEAS) provides us a convenient and most sensitive tool to measure low molecular weight, redox-active compounds in biological sample. The deproteinized sample was analyzed on a HPLC coupled with a 16-channel CMEAS, which incremented from 60 to 960 mV in 60 mV steps. Each sample was run on a single column (Meta-250, 4.6 × 250 mm) under a 150-minute complex gradient that ranged from 0% B (A: 1.1% pentane sulfonic acid) to 20% B (B: 0.1 m lithium acetate in mixture of methanol, acetonenitrile and isopropanol), with a flow rate of 0.5 mL/min. We have developed an automated procedure to simultaneously measure various antioxidant, oxidative stress marker, and monoamine metabolites in a single column with binary gradient. No other chemical reactions are necessary. In order to reduce the running time and yet achieve a reproducible retention time by the autosampler injection, our gradient elution profile was modified to produce a shorter equilibration time and to compensate for the initial contamination of mobile phase B following the first injection. Without the use of two columns in series and peak suppresser/gradient mixer, we have simplified the previously published method to measure over 20 different antioxidants, oxidative stress markers and monoamine metabolites simultaneously in biological samples. [source] Lewis Base Catalyzed Mannich-Type Reactions between Trimethylsilyl Enol Ethers and AldiminesCHEMISTRY - A EUROPEAN JOURNAL, Issue 19 2006Hidehiko Fujisawa Abstract Lewis base catalyzed Mannich-type reaction between trimethylsilyl enol ethers and N -tosylaldimines is described. Nitrogen anions generated from amides or imides such as lithium benzamide or potassium phthalimide are found to be effective Lewis base catalysts in DMF at room temperature to afford the corresponding ,-amino carbonyl compounds in good to high yields; the oxygen anion generated from carboxylic acids such as lithium acetate was also found to be effective in dry DMF. The above-mentioned lithium acetate-catalyzed Mannich-type reaction between aldimines and various trimethylsilyl (TMS) enol ethers such as silyl ketene acetal proceeded smoothly even in water-containing DMF. Then, Lewis base catalyzed three-component Mannich-type reactions of TMS enol ether, tosylamide, and aromatic aldehyde having electron-withdrawing group such as p -nitrobenzaldehyde were investigated. The reaction proceeded smoothly to afford the corresponding ,-amino ester in good yield. Further, ammonium carboxylates such as tetrabutyl ammonium acetate or tetrabutyl ammonium benzoate were found to be more effective Lewis base catalysts in the above-mentioned Mannich-type reaction. The synthesis proceeded in various solvents at lower temperatures. The reaction between aldimines and TMS enol ethers generated from thioester and various ketones such as propiophenone or cyclohexanone also proceeded smoothly to afford the corresponding ,-amino carbonyl compounds in high yields with good to high anti -selectivities. [source] | ||||||||||