Search results for "Bromide"
showing 10 items of 591 documents
Physicochemical compatibility of nebuliser solution admixtures containing colistimethate and hypertonic saline or colistimethate, fluticasone-17-prop…
2012
Objectives For practical reasons, patients with cystic fibrosis (CF) tend to mix different inhalation solutions for concomitant inhalation instead of inhaling the different medications consecutively. A study was undertaken to examine the compatibility of colistimethate dissolved in 5.85% hypertonic sodium chloride (NaCl) solution and the quadripartite mixtures of colistimethate, fluticasone-17-propionate, ipratropium bromide and salbutamol sulfate. Methods The test solutions were prepared by mixing ordinary doses of the inhalation products and analysed immediately. Microbiological assays of antibiotics and high-performance liquid chromatography assays were used to determine chemical compati…
Calorimetric investigation of the complex formation between surfactants and α-, β- and γ-cyclodextrins
1992
Abstract A calorimetric technique has been used to study complex formation between α-, β- and γ-cyclodextrins (αCD, βCD and γCD) and some surfactants (sodium dodecylsulphate (SDS), hexadecyl trimethylammonium bromide (CTAB) and p-(1,1,3,3-tetramethylbutyl) phenoxypoly(oxyethyleneglycol) (Triton X-100)). The experimental data indicate that some complexes (SDS-αCD, SDS-βCD and CTAB-αCD) are very stable and allow direct determination of their stoichiometry and molar enthalpy of complex formation. Those for other complexes closely fit a model based on an equilibrium reaction between surfactant, cyclodextrin and a single complex. According to the model, data analysis allows determination of the …
Cyclic fatty acid monomers : synthesis and characterization of methyl w-(2-alkylcyclopentyl) alkenoates and alkanoates
1988
Abstract Some 1,2-disubstituted cyclopentanes were synthesized. These were methyl 9-(2-butyl-cyclopentyl)-8-nonenoate, methyl 7-(2-hexyl-cyclopentyl)-6-heptenoate and methyl 5-(2-octyl-cyclopentyl)-4-pentenoate and their corresponding alkanoates. The synthesis involved a Michael addition of alkylmagnesium bromide to an unsaturated cyclic ester. The resulting cis and trans ethyl 2-alkylcyclopentane carboxylate were further converted to the alcohols then to the aldehydes. The aldehydes were condensed with the ylide derived from the (ω-carboxyalkyl)-triphenylphosphonium bromide and methylsulfinylmethide in DMSO to give unsaturated C18 cyclic fatty acid monomers. These cyclic fatty acids were f…
High yield recombinant production of a self-assembling polycationic peptide for silica biomineralization.
2015
We report the recombinant bacterial expression and purification at high yields of a polycationic oligopeptide, P5S3. The sequence of P5S3 was inspired by a diatom silaffin, a silica precipitating peptide. Like its native model, P5S3 exhibits silica biomineralizing activity, but furthermore has unusual self-assembling properties. P5S3 is efficiently expressed in Escherichia coli as fusion with ketosteroid isomerase (KSI), which causes deposition in inclusion bodies. After breaking the fusion by cyanogen bromide reaction, P5S3 was purified by cation exchange chromatography, taking advantage of the exceptionally high content of basic amino acids. The numerous cationic charges do not prevent, b…
Synthese und Reaktionen der 3-O-Phosphoniogluco-und -allofuranosen
1982
Aus den bicyclischen Gluco- (3, 5, 7 und 9) und Allofuranosen 11 werden mit Triphenylphosphan (1), Azodicarbonsaure-diethylester (2) und Alkylierungs- oder Acylierungsmitteln isolierbare 3-O-Phosphoniokohlenhydrate (4, 6, 8, 10 und 12) hergestellt. Durch Erwarmen der allo-konfigurierten Salze 12 konnen an C-3 epimere gluco-konfigurierte Substitutionsprodukte in groser Vielfalt gewonnen werden. Die Reaktionen der gluco-konfigurierten Salze werden stark vom Charakter des einzufuhrenden Nucleophils und von Nachbargruppen im Kohlenhydratgerust beeinflust. Wahrend das Iodid 4a und das Azid 4g unter Substitution zum allo-Derivat 15 reagieren, tritt in den Fallen mit Bromid, Chlorid oder Sulfonat …
Unprecedented ring cleavage in the reaction of 1-methyl-3-phenacyl benzimidazolium ylide with diethyl azodicarboxylate
2010
The reaction with diethyl azodicarboxylate (DEAZD) of different cycloimmonium ylides derived from pyridinium, quinolinium, isoquinolinium and 1-methylbenzimidazolium bromides (3, 4, 5 and 6) yielded 3-substituted tetraazapentenes (2). In the special case of 1-methyl-3-phenacyl-benzimidazolium bromide (6a), the ring cleavage compound N-[1-[(ethoxycarbonyl)amino]-2-oxo-2-phenylethylidene]-N-formyl-N-methyl-1,2-benzenediamine (7a) was obtained. Its structure was established by X-ray crystallography.
Synthese von Giycopeptiden: Selektive C-terminale Deblockierung und Peptidkettenverlängerung an Glucosylserin-Derivaten
1983
Benzyloxycarbonyl-(Z-)serin-2-bromethylester (3b) wird mit 2,3,4,6-Tetra-O-benzoyl-α-D-gluco-pyranosylbromid (14) zum Glucosylserinester 15 verknupft. Nach Umwandlung in den entsprechenden 2-Iodethylester 23 wird die Carboxygruppe durch Eliminierung mit Zink selektiv deblockiert. Dabei bleiben die Z- und die Kohlenhydrat-Schutzgruppen sowie die empfindliche O-glycosidische Bindung unverandert erhalten. Das Glycosyl-Z-serin 24 reagiert mit Aminosaure-2-bromethylestern 2 zu geschutzten Glycodipeptid-2-bromethylestern 18, die nach selektiver Carboxydeblockierung zu Glycotripeptidestern 25 C-terminal verlangert werden. Wahrend geschutzte Serin-Dipeptide 5 mit 14 zu Konjugaten 18 glycosyliert we…
High efficiency joint CZE determination of sugars and acids in vegetables and fruits
2012
In this work, an improved CE method for the medium-throughput determination of main organic acids (oxalate, malate, citrate), the amino acid glutamate and the sugars fructose, glucose and sucrose in several food matrices is described. These compounds have been identified as key components in the taste intensity of fruit and vegetable crops. Using a running buffer with 20 mM 2,6-pyridine dicarboxylic acid pH 12.1 and 0.1% hexadimethrine bromide, replacing it every 5 h to avoid pH decrease, and optimizing capillary conditioning between runs with 58 mM SDS during 2 min at 20 psi, it is possible to effectively quantify these compounds while increasing medium throughput repeatability. This proce…
C-Methyl resorcin[4]arene packing motifs with alkyl ammonium salts: From molecular capsules to channels and tubes
2005
A variety of packing motifs of C-methyl resorcinarene were obtained when complexed with small alkyl ammonium salts of different size and shape. Using bromide and chloride salts of the small quaternary alkyl ammonium cations, tetramethyl ammonium and dimethyldiethyl ammonium, leads to a grid-like packing of solvent mediated dimeric capsules while the use of salts of larger diquaternary cations bearing a 1,4-diazabicyclo[2.2.2]octane (DABCO) scaffold produces solvent/anion mediated chains and channels or tubular structures. The connecting interactions between resorcinarenes in each structure are hydrogen bonding and/or π⋯π interactions.
Bromide hydrogen oxalate salts with the diprotonated 1,4-diazabicyclo[2.2.2]octane counterion
2020
Abstract Two new salts composed of the diprotonated 1,4-diazabicyclo[2.2.2]octane (DABCO) molecule as the cations and bromide and hydrogen oxalate as the anions have been isolated and structurally characterized by X-ray diffraction analysis. The salt [DABCOH2]{[HC2O4][Br]} (1) crystallizes in the orthorhombic system, space group P212121 with a = 9.0809(7), b = 9.5156(7), c = 12.3558(9) Å, V = 1067.67(14) Å3 and Z = 4. The salt [DABCOH2]2{[HC2O4][Br]3}·H2O (2) crystallizes in the orthorhombic system, space group Pnma with a = 26.6554(17), b = 7.3711(4), c = 10.7421(7) Å, V = 2110.6(2) Å3 and Z = 4. The compounds were prepared from ethanolic solutions of [DABCOH2][HC2O4]2 (L 1 ) and ZnBr2 in …