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Sodium Bromide (sodium + bromide)
Selected AbstractsBromination of Activated Arenes by Oxone® and Sodium Bromide.CHEMINFORM, Issue 35 2002Kee-Jung Lee Abstract For Abstract see ChemInform Abstract in Full Text. [source] Synthesis and Properties of New Nucleotide Analogues Possessing Squaramide Moieties as New Phosphate Isosters,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 24 2005Kohji Seio Abstract New analogues of 2,-deoxynucleotides and ribonucleotides incorporating a unique squaramide structure were synthesized. Because of the strong acidity of this moiety (pKa = 2.3), these nucleotide analogues exist in a monoanionic form, which can be regarded as an electronic isoster of 5,-nucleotides under physiological conditions. The synthesis of the nucleotide analogues was achieved through the condensation of 5,- or 3,-aminonucleosides with dimethyl squarate, whilst the selective removal of the methyl group was effectively accomplished by treatment with sodium bromide. In addition, we also synthesized 3,,5,-cyclic nucleotide analogues from the 3,,5,-diazidonucleoside derivatives. NMR analysis revealed that their ribose puckering was of an N-type form, identical to that in cAMP and cGMP. Because of the unique structural, electronic, and conformational properties of squaramide-type nucleotide analogues, these analogues should be quite interesting as potential biologically active compounds such as antiviral and anticancer agents. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Highly Efficient Halogenation of Organic Compounds with Halides Catalyzed by Cerium(III) Chloride Heptahydrate Using Hydrogen Peroxide as the Terminal Oxidant in WaterADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Habib Firouzabadi Abstract In this article a new environmentally friendly catalytic method is described for the efficient monoiodination and bromination of arenes and also iodoetherification and iodolactonization of olefins using hydrogen peroxide as the terminal oxidant. The method is based on using sodium iodide or sodium bromide, hydrogen peroxide (35%) and cerium(III) chloride as an effective catalyst in water at room temperature or under reflux conditions. By this protocol, iodination of anilines proceeded with high regioselectivity at the para position with the formation of small amounts of the ortho isomers. However, bromination of anilines proceeded with absolute regioselectivity to give the para isomers as the sole products in high yields. Iodinations and brominations of m -xylene, toluene, chloro- and bromobenzenes were proceeded with excellent regioselectivity to produce the para isomers as the sole products. Benzene was also halogenated by this catalytic system to give the monohalogenated benzene in good yields. Iodoetherification and iodolactonization of olefins also proceeded easily in high yields at room temperature. However, the bromination of olefins by this protocol failed and the starting materials were detected intact. [source] Physicochemical Properties of Cellulose Selectively Oxidized with the 2,2,6,6-Tetramethyl-1-Piperidinyl Oxoammonium IonJOURNAL OF FOOD SCIENCE, Issue 5 2007D.S. Suh ABSTRACT:, This study examined the characteristics of the oxidation reaction on the primary alcohol groups in cellulose involving the 2,2,6,6-tetramethyl-1-piperidinyl oxoammonium ion (TEMPO) and determined the optimum conditions for the preparation of oxidized cellulose (OC). The applicability of OC in polysaccharide systems was also investigated. The effects of TEMPO, sodium bromide (NaBr), and temperature on the oxidation reaction time, yield, and selectivity for primary alcohol groups were examined using response surface methodology (RSM). The reaction time decreased with increases in the temperature and the levels of TEMPO and NaBr. The yield increased with the level of NaBr and decreased as the temperature increased. Selectivity increased with the temperature and decreased as the levels of TEMPO and NaBr increased. The optimum levels of TEMPO and NaBr and the optimum temperature for the production of OC were determined as 0.3 mM/100 mM anhydroglucose unit (AGU), 50 mM/100 mM AGU, and 25 °C, respectively. The water and oil binding capacity and viscosity of cellulose increased with oxidation. Wheat starch containing OC exhibited a decreased initial pasting temperature and setback, but increased peak viscosity, gelatinization, and retrogradation enthalpy (,H). The hardness of the wheat starch gel decreased significantly upon the addition of OC. [source] An efficient process for synthesizing and hydrolyzing a phosphonated methacrylate: Investigation of the adhesive and anticorrosive propertiesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 14 2008Zhor El Asri Abstract A new phosphonated methacrylate, namely dimethyl(methacryloyloxy)methyl phosphonate (MAPC1), has been synthesized using paraformaldehyde and potassium carbonate according to the Pudovik reaction. The quantitative synthesis of MAPC1 was followed by selective hydrolysis of the ester group with sodium bromide to replace NaI (imparting non-negligible ecological impact). Pure MAPC1(OH) was obtained in high yield and efficiently copolymerized with MMA. The r1 for MAPC1(OH)) and r2 (for MMA) values are 0.99 and 1.02, respectively, which indicates that the monophosphonic groups are statistically linked to the methacrylate backbone. When blended with PVDF, MMA/MAPC1(OH) copolymers show very good adhesion promoters in both dry and wet conditions and subsequently provide good anticorrosive properties. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4794,4803, 2008 [source] Outer membrane proteome of Actinobacillus pleuropneumoniae: LC-MS/MS analyses validate in silico predictionsPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 11 2007Jacqueline W. Chung Abstract The Gram-negative bacterial pathogen Actinobacillus pleuropneumoniae causes porcine pneumonia, a highly infectious respiratory disease that contributes to major economic losses in the swine industry. Outer membrane (OM) proteins play key roles in infection and may be targets for drug and vaccine research. Exploiting the genome sequence of A. pleuropneumoniae serotype 5b, we scanned in silico for proteins predicted to be localized at the cell surface. Five genome scanning programs (Proteome Analyst, PSORT-b, BOMP, Lipo, and LipoP) were run to construct a consensus prediction list of 93 OM proteins in A. pleuropneumoniae. An inventory of predicted OM proteins was complemented by proteomic analyses utilizing gel- and solution-based methods, both coupled to LC-MS/MS. Different protocols were explored to enrich for OM proteins; the most rewarding required sucrose gradient centrifugation followed by membrane washes with sodium bromide and sodium carbonate. This protocol facilitated our identification of 47 OM proteins that represent 50% of the predicted OM proteome, most of which have not been characterized. Our study establishes the first OM proteome of A. pleuropneumoniae. [source] Synthesis of novel stereodefined vinylgermanes bearing an allyl group or an allenyl group: (E)-2-aryl-1-germylalka-1,4-dienes and (E)-4-aryl-5-germylpenta-1,2,4-trienes,APPLIED ORGANOMETALLIC CHEMISTRY, Issue 7 2007Kotaro Kato Abstract Stereodefined synthesis of an unprecedented family of vinylgermanes bearing an allyl group, (E)-2-aryl-1-germylalka-1,4-dienes, or an allenyl group, (E)-4-aryl-5-germylpenta-1,2,4-trienes, via a cross-coupling reaction of (Z)-germyl(stannyl)ethenes with the respective allyl halide (Br, Cl) and propargyl bromide is described. In the reaction with allyl halides, either a Pd(dba)2,CuI combination (dba: dibenzylideneacetone) or CuI alone readily catalyzes or mediates the coupling reaction of (Z)-germyl(stannyl)ethenes, producing the novel vinylgermanes bearing an allyl group. The thienyl group or hydroxy group of the (Z)-germyl(stannyl)ethene survives the reaction. Copper(I) iodide alone readily mediates the reaction with allyl chloride or methallyl chloride upon addition of sodium bromide to produce the respective cross-coupled product in good yield. In contrast, crotyl halides (Br, Cl) or prenyl chloride couple with/without allylic transposition in the bromide or the chloride. In the reaction with propargyl bromide, a Pd(dba)2 and CuI combination efficiently drives the coupling reaction of (Z)-germyl(stannyl)ethenes in NMP (N -methylpyrrolidone), providing the stereochemically defined allenyl vinylgermanes, (E)-4-aryl-5-germylpenta-1,2,4-trienes, in good yields. Copyright © 2007 John Wiley & Sons, Ltd. [source] Crystallization and preliminary X-ray diffraction studies of a mosquito-larvicidal toxin from Bacillus thuringiensis subsp. israelensisACTA CRYSTALLOGRAPHICA SECTION D, Issue 3 2003Panadda Boonserm The Cry4B ,-endotoxin from Bacillus thuringiensis subsp. israelensis is specifically toxic to mosquito larvae. For a better understanding of the mechanism of toxicity, chymotrypsin-activated Cry4B toxin (68,kDa) has been purified and crystallized in sodium bromide at neutral pH. The well formed crystals belong to the rhombohedral space group R32, with unit-cell parameters a = b = 185.82, c = 187.93,Å, and diffracted X-rays to 1.75,Å resolution. The asymmetric unit contains one toxin molecule and 74% solvent content, as shown by molecular replacement from a composite model of the homologous Cry3A and Cry1Aa. The purified protein and crystals both possessed mosquitocidal activity. [source] | ||||||||||