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Aldehydes were found to be oxidized with molecular oxygen to the corresponding carboxylic acid in the presence of catalytic hydrobromic acid or bromine under photo-irradiation.
We describe the clinical course of two patients who developed acute pneumonitis followed by reactive airways dysfunction syndrome after bathing in a hot tub. Additional findings were present and suggested that exposure to a corrosive agent was responsible. Bromine and hydrobromic acid generated from a widely used water disinfectant were implicated as the underlying cause. Physicians should be alert to the possibility that such exposures may initiate or exacerbate inflammatory pulmonary disease.
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A simple and rapid liquid-liquid extraction of palladium has been studied involving ion-pairing of bromocomplexes of palladium(II) with hexadecylpyridinium bromide (HDPB) dissolved in chloroform. The stoichiometry and distribution of (HDP)2PdBr4 between the aqueous and organic phase was investigated by spectrophotometric mole ratio method. The extraction efficiency of palladium(II) by HDPB was studied as a function of several variables: acid, salt, surfactant concentration and equilibrium time. The results showed that PdBr4(2-) extraction could be explained by assuming the formation of (HDP)2PdBr4 complexes in the aqueous solution and transfer to organic phase. The extraction was fast and the shaking time was only a few min. The average recovery of palladium(II) from an aqueous solution containing 10 microg/ml of analyte was 99% with an RSD% of 0.95. The percentage recovery of 0.2 microg/ml palladium(II) was 96%.
(Benzotriazol-1-ylmethyl)benzenes and -naphthalenes 1a-f, easily accessible from benzyl bromides and benzotriazole, readily undergo lithiation and subsequent 1,4-addition to alpha,beta-unsaturated aldehydes and ketones. Intramolecular cyclization of the products, induced by acetic acid-hydrobromic acid or polyphosphoric acid (PPA), followed by simultaneous dehydration and debenzotriazolylation furnishes a wide range of polysubstituted naphthalenes 7a-f and of phenanthrenes 9 and 11 in moderate to good yields in one-pot procedures. If compounds 1 are first lithiated and reacted with electrophiles, the resulting alkylation products undergo similar annulation reactions with alpha,beta-unsaturated carbonyl compounds to provide the more highly substituted naphthalenes 6a,b and phenanthrenes 10a,b in moderate overall yields.
A new sampling method has been developed for the measurement of ethylene oxide (EtO) exposures in the workplace. This sampling method uses a hydrobromic acid-coated charcoal tube to collect EtO as its 2-bromoethanol reaction product. Because 2-bromoethanol is less volatile and less reactive than EtO, improved sampling capacity and sample stability are observed with this method over the collection of EtO on untreated charcoal. Sample analysis is performed by gas chromatography with electron capture detection (GC/ECD) following desorption with dimethylformamide (DMF) and derivatization of the 2-bromoethanol reaction product with heptafluorobutyrylimidazole (HFBI). The direct analysis of 2-bromoethanol by GC/ECD was not reproducible and this effect was attributed to the presence of excess hydrobromic acid (HBr) in the sample. This matrix effect was eliminated by the formation of the heptafluorobutyrate ester, a water-insoluble derivative of 2-bromoethanol, which was extracted into iso-octane for analysis. This analytical scheme is very sensitive and was used to monitor test atmospheres of EtO at the 0.1 ppm level. An average recovery of 96% was obtained for short-term samples (15 minutes) collected from a 5-ppm test atmosphere at 23 degrees C and 80% relative humidity. Similar high recoveries were obtained for 4-hr samples collected at a sampling rate of 0.1 L/min from test atmospheres in the concentration range of 0.1 to 16 ppm EtO at high humidity (80%) and ambient temperature (22 degrees C to 25 degrees C). Samples collected under these same conditions and stored for a minimum of 2 weeks resulted in average recoveries that ranged from 84% to 101%. Average recoveries of 97% were obtained for 2-ppm air samples collected at low humidity with no storage; however, storage of these samples at 22 degrees C to 25 degrees C resulted in an approximate loss of 5% per week. A field comparison study of samples, that was obtained from a hospital sterilization facility, used the test method and the Qazi-Ketchum sample method and resulted in a correlation for paired samples of 0.99 over a concentration range of 0.3 to 7.0 ppm EtO. These results indicate that this sampling and analytical method is a convenient, accurate and reliable means of monitoring EtO exposures in the workplace.
C2-Alkyl substituted derivatives of the 1,1,2-tris(4-hydroxyphenyl)ethene 3a (alkyl = Me (3b), Et (3c), Prop (3d), But (3e)) were synthesized by reaction of 1,2-bis(4-methoxyphenyl)ethanone with the appropriate alkyl halide, followed by a Grignard reaction with 4-methoxyphenylmagnesium bromide, dehydration with phosphoric acid or hydrobromic acid, and ether cleavage with BBr(3). The compounds were tested for estrogen receptor (ER) binding affinity in a competition experiment with radio labeled estradiol ([(3)H]-E2) and for gene activation on the ER-positive MCF-7-2a cell line. All compounds showed high receptor binding affinity (RBA-value: 3b (52.1%) > 3a (45.5%) > 3c (29.6%) > 3d (4.03%) > 3e (0.95%)). The tests on hormone dependent MCF-7-2a breast cancer cells, stably transfected with the plasmid ERE(wtc)luc, revealed that all 1,1,2-tris(4-hydroxyphenyl)ethenes antagonized the effect of 1 nM estradiol (E2). The compounds 3b (IC(50) = 15 nM) and 3c (IC(50) = 10 nM) were equal in their effects to 4-hydroxytamoxifen (4OHT) (IC(50) = 7 nM). Agonistic effects were low. Only 3a and 3b activated the luciferase expression (relative activation at 1 microM: 3a 60%; 3b 35%). Despite their highly antagonistic potency, the 1,1,2-tris(4-hydroxyphenyl)ethenes showed only low cytotoxic properties on the hormone sensitive MCF-7 cell line.
N-n-octylaniline in xylene is used for the extractive separation of gold(III) from halide media. Gold(III) was extracted quantitatively with 10 ml of 2% reagent in xylene from 0.5-10 M and 0.5-8 M hydrochloric acid and hydrobromic acid, respectively. It was stripped from the organic phase with ammonia buffer solution (pH 10.1) and estimated spectrophotometrically with stannous chloride. The effect of metal ion, acids, reagent concentration and of various foreign ions has been investigated. Method is applicable to the analysis of synthetic mixtures containing platinum metals and alloy samples. The method is fast, accurate and precise.
Primary and secondary ion exchanges--of hydrochloric acid and hydrobromic acid salts of well hydrolyzing organic bases as well as quaternary ammonium bromide which are important drug substance--taking place on silica gel using methanol as mobile phase have been investigated by thin-layer chromatographic and spectrophotometric methods. In case of tertiary ammonium salts (hydrolyzing salts) basis linked to silanate ion and halogen acid have been formed by primary ion exchange. During secondary ion exchange halogen acid has exchanged metal ions linked to silanate ions on the layer. In case of non hydrolyzing salts, the quaternary ammonium bromide salts it could not surely be proved by the applied methods whether primary ion exchange had been followed by secondary ion exchange or only primary ion exchange had occurred.