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Potassium Cyanide (potassium + cyanide)
Selected AbstractsNovel Enantioselective Synthesis of Functionalized Pyridylarsanes by a Chiral Palladium Template Promoted Asymmetric Hydroarsanation ReactionEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 27 2009Fengli Liu Abstract The asymmetric hydroarsanation reactions between diphenylarsane and (E)-1-phenyl-3-(pyridin-2-yl)-2-propenone and (E)-1-methyl-3-(pyridin-2-yl)-2-propenoate have been achieved by use of the organopalladium complex containing ortho -metalated (R)-[1-(dimethylamino)ethyl]naphthalene as the chiral reaction template in high regio- and stereoselectivities under mild conditions. Hydroarsanation of (E)-1-phenyl-3-(pyridin-2-yl)-2-propenone with diphenylarsane generated two stereoisomeric products in the ratio of 3:1 as five-membered As,N bidentate chelates on the chiral naphthylamine palladium template. Using the same chiral metal template, the corresponding hydroarsanation reaction with (E)-1-methyl-3-(pyridin-2-yl)-2-propenoate gave only one product as a six-membered As,N bidentate chelate. The naphthylamine auxiliary could be removed chemoselectively by treatment with concentrated hydrochloric acid to form the corresponding optically pure neutral complexes. Subsequent ligands displacement from the palladium using aqueous potassium cyanide generated the optically pure keto- and ester-functionalized chiral pyridylarsane ligands. The absolute configuration and the coordination properties of the pyridylarsanes have been established by single-crystal X-ray analysis.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Sympathoexcitatory response to peripheral chemoreflex activation is enhanced in juvenile rats exposed to chronic intermittent hypoxiaEXPERIMENTAL PHYSIOLOGY, Issue 6 2006Valdir A. Braga In the present study, we tested the hypothesis that chronic intermittent hypoxia (CIH) produces changes in the autonomic and respiratory responses to acute peripheral chemoreflex activation. To attain this goal, 3-week-old rats were exposed to 10 days of CIH (6% O2 for 40 s at 9 min intervals; 8 h day,1). They were then used to obtain a working heart,brainstem preparation and, using this unanaesthetized experimental preparation, the chemoreflex was activated with potassium cyanide (0.05%, injected via the perfusion system), and the thoracic sympathetic nerve activity (tSNA), heart rate and phrenic nerve discharge (PND) were recorded. Rats subjected to CIH (n= 12), when compared with control animals (n= 12), presented the following significant changes in response to chemoreflex activation: (a) an increase in tSNA (78 ± 4 versus 48 ± 3%); (b) a long-lasting increase in the frequency of the PND at 20 (0.52 ± 0.03 versus 0.36 ± 0.03 Hz) and 30 s (0.40 ± 0.02 versus 0.31 ± 0.02 Hz) after the stimulus; and (c) a greater bradycardic response (,218 ± 20 versus,163 ± 16 beats min,1). These results indicate that the autonomic and respiratory responses to chemoreflex activation in juvenile rats previously submitted to CIH are greatly increased. [source] Construction of Recombinant Escherichia coli Catalysts which Simultaneously Express an (S)-Oxynitrilase and Different Nitrilase Variants for the Synthesis of (S)-Mandelic Acid and (S)-Mandelic Amide from Benzaldehyde and CyanideADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2009Olga Sosedov Abstract Recombinant Escherichia coli strains were constructed which simultaneously expressed the genes encoding the (S)-oxynitrilase from cassava (Manihot esculenta) together with the wild-type or a mutant variant of the arylacetonitrilase from Pseudomonas fluorescens EBC191 in a single organism under the control of a rhamnose-inducible promoter. The whole cell catalysts obtained converted benzaldehyde and potassium cyanide in aqueous media at pH,5.2 mainly to (S)-mandelic acid and/or (S)-mandelic amide and synthesized only low amounts of the corresponding (R)-enantiomers. The conversion of benzaldehyde and potassium cyanide (KCN) by a whole-cell catalyst simultaneously expressing the (S)-oxynitrilase and the wild-type nitrilase resulted in a ratio of (S)-mandelic acid to (S)-mandelic amide of about 4:3. This could be explained by the strong nitrile hydratase activity of the wild-type nitrilase with (S)-mandelonitrile as substrate. The relative proportion of (S)-mandelic amide formed in this system was significantly increased by coexpressing the (S)-oxynitrilase with a carboxy-terminally truncated variant of the nitrilase. This whole-cell catalyst converted benzaldehyde and KCN to mandelic amide and mandelic acid in a ratio of about 9:1. The ee of the (S)-mandelic amide formed was calculated to be >95%. [source] Blood Cyanide Determination in Two Cases of Fatal Intoxication: Comparison Between Headspace Gas Chromatography and a Spectrophotometric Method*JOURNAL OF FORENSIC SCIENCES, Issue 6 2007Veniero Gambaro M.Sc. Abstract:, Blood samples of two cases were analyzed preliminarily by a classical spectrophotometric method (VIS) and by an automated headspace gas chromatographic method with nitrogen-phosphorus detector (HS-GC/NPD). In the former, hydrogen cyanide (HCN) was quantitatively determined by measuring the absorbance of chromophores forming as a result of interaction with chloramine T. In the automated HS-GC/NPD method, blood was placed in a headspace vial, internal standard (acetonitrile) and acetic acid were then added. This resulted in cyanide being liberated as HCN. The spectrophotometric (VIS) and HS-GC/NPD methods were validated on postmortem blood samples fortified with potassium cyanide in the ranges 0.5,10 and 0.05,5 ,g/mL, respectively. Detection limits were 0.2 ,g/mL for VIS and 0.05 ,g/mL for HS-GC/NPD. This work shows that results obtained by means of the two procedures were insignificantly different and that they compared favorably. They are suitable for rapid diagnosis of cyanide in postmortem cases. [source] A convenient racemic synthesis of two isomeric tetrahydropyridyl alkaloids: Isoanatabine and anatabineJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 3 2010Anne Rouchaud Anatabine is a major alkaloid in Nicotiana tabacum and its isomer, isoanatabine, was recently found in a marine worm. Reduction of 1-methylpyridinium iodide with sodium borohydride gave 1-methyl-3-piperideine, which was transformed with hydrogen peroxide into the N -oxide. Reaction of the N -oxide successively with trifluoroacetic anhydride and potassium cyanide gave 2-cyano-1-methyl-3-piperideine. Its reaction with 3-pyridylmagnesium chloride gave (±)- N- methyl-isoanatabine. This was transformed with m -chloroperbenzoic acid into the N -oxide which was N -demethylated with iron(II) sulfate, giving (±)-isoanatabine. The successive applications of literature procedures for the N -demethylation by decomposition of N -oxide contributed to the knowledge of the mechanism of this oxidative rearrangement. On the other hand, the reduction of 1-methylpyridinium iodide with sodium borohydride and with potassium cyanide present since the start of the reaction in a two layer ether-water system, gave 2-cyano-1-methyl-4-piperideine. This was transformed into (±)-anatabine by the same sequence of reactions used for the synthesis of (±)-isoanatabine. J. Heterocyclic Chem., (2010). [source] Synthesis of spirolactones by 1,3-dipolar cycloadditions to methyl (S)-3-[(E)-cyanomethylidene]-2-oxotetrahydrofuran-5-carboxylateJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 2 2002Samo Pirc Dedicated to Professor Emeritus Miha Ti,ler on the occasion of his 75th birthday Treatment of methyl (S)-5-[(E)-(dimethylamino)methylidene]-2-oxotetrahydrofuran-5-carboxylate (2) with potassium cyanide in acetic acid gave (S)-5-[(E)-cyanomethylidene]-2-oxotetrahydrofuran-5-car-boxylate (3), which was used as chiral dipolarophile in 1,3-dipolar cycloadditions. Reactions of 3 with diazomethane (4) and nitrile oxides 5a-c afforded spirolactones 6,8 in 24-34% diastereomeric excess, while with diazomethane (4) in the presence of triethylamine, methyl 3-cyanomethyl-2-methoxyfuran-5-carboxylate (12) was obtained. [source] An efficient large-scale synthesis of 1H -indazole-[3- 14C]carboxylic acidJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 7 2007Richard V. Coelho Jr. Abstract An efficient large-scale carbon-14 synthesis of 1H -indazole-[3- 14C]carboxylic acid starting from [14C]potassium cyanide is reported. Key transformations encountered during the synthesis include aromatic nucleophilic substitution of 2-nitrofluorobenzene by ethyl [14C]cyanoacetate, a mild decarbethoxylation and an aniline nitrosation/cyclization. Copyright © 2007 John Wiley & Sons, Ltd. [source] Convergent synthesis of two 14C-labeled ,3 -adrenergic receptor agonistsJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 8 2006Boris A. Czeskis Abstract The synthesis of ,3 -adrenergic receptor agonists A and B with radiolabeled amide fragment, required for drug disposition studies, was accomplished based on initial formation of 2-(4-(2-amino-2-methylpropyl)phenoxy)-5-[14C]-cyanopyridine by the reaction of 2-bromo-5-iodopyridine with para -substituted phenol, and following cyanation of aromatic iodide with potassium cyanide-[14C]. After the coupling of the resulted amine with glycidyl derivatives of 4-hydroxyindole and 4-hydroxycarbazole, the corresponding nitriles were hydrolyzed with basic hydrogen peroxide to obtain target amides A and B. Copyright © 2006 John Wiley & Sons, Ltd. [source] The syntheses of [14C] and [13C2,15N3]aprepitantJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 12 2004Charles S. Elmore Abstract In support of a program to develop a treatment for chemotherapy-induced nausea and vomiting, two isotopically labeled forms of neurokinin-1 receptor antagonist aprepitant have been synthesized. A [l4C]-labeled version was synthesized for use in metabolism studies, while a [13C2,15N3]-labeled version was synthesized for use in a study to determine the bioavailability of the final market image. Both syntheses utilized labeled chloroacetonitrile which was synthesized in two steps from labeled potassium cyanide. Copyright © 2004 John Wiley & Sons, Ltd. [source] Development of a method for quantitative analysis of the major whey proteins by capillary electrophoresis with on-capillary derivatization and laser-induced fluorescence detectionJOURNAL OF SEPARATION SCIENCE, JSS, Issue 9-10 2005María Teresa Veledo Abstract The main whey proteins have been derivatized on-capillary with 3-(2-furoyl)quinoline-2-carboxaldehyde (FQ) and analyzed using a laboratory-made capillary electrophoresis apparatus provided with a laser-induced fluorescence detector. Several parameters controlling on-capillary derivatization of proteins, including pH, mixing time, reaction time, concentration of the reagents (potassium cyanide and FQ), and reaction temperature, were optimized. Coefficient variations were lower than 1% for migration time and 7% for peak height. Assay detection limits for the different proteins were in the range 5 nM to 10 nM. The method developed was applied to the separation of the major whey proteins in a laboratory-made cheese whey and in an infant food formulated with milk. In addition, the ,-LG content of these samples was quantitated. The results showed good agreement with those given by an RP-HPLC method and with those reported in the literature. [source] Parkinsonism and cognitive impairment following chronic exposure to potassium cyanideMOVEMENT DISORDERS, Issue 3 2008Massimiliano Di Filippo MD [source] Inhibitory effect of bionic fungicide 2-allylphenol on Botrytis cinerea (Pers. ex Fr.) in vitro,PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 12 2009Shuangjun Gong Abstract BACKGROUND: 2-Allylphenol is a registered fungicide in China to control fungal diseases on tomato, strawberry and apple. It is synthetic and structurally resembles the active ingredient ginkgol isolated from Ginkgo biloba L. bark. 2-Allylphenol has been used in China for 10 years. However, its biochemical mode of action remains unclear. An in vitro study was conducted on the biochemical mechanism of 2-allyphenol inhibiting Botrytis cinerea (Pers. ex Fr.). RESULTS: The inhibition was approximately 3 times stronger when the fungus was grown on non-fermentable source, glycerol, than that on a fermentable carbon source, glucose. Inhibition of B. cinerea and Magnaporthe oryzae (Hebert) Barr mycelial growth was markedly potentiated in the presence of salicylhydroxamic acid (SHAM), an inhibitor of mitochondrial alternative oxidase. Furthermore, at 3 h after treatment with 2-allylphenol, oxygen consumption had recovered, but respiration was resistant to potassium cyanide and sensitive to SHAM, indicating that 2-allylphenol had the ability to induce cyanide-resistant respiration. The mycelium inhibited in the presence of 2-allylphenol grew vigorously after being transferred to a fungicide-free medium, indicating that 2-allylphenol is a fungistatic compound. Adenine nucleotide assay showed that 2-allylphenol depleted ATP content and decreased the energy charge values, which confirmed that 2-allylphenol is involved in the impairment of the ATP energy generation system. CONCLUSION: These results suggested that 2-allylphenol induces cyanide-resistant respiration and causes ATP decrease, and inhibits respiration by an unidentified mechanism. Copyright © 2009 Society of Chemical Industry [source] P450-catalyzed vs. electrochemical oxidation of haloperidol studied by ultra-performance liquid chromatography/electrospray ionization mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 9 2010Tove Johansson Mali'n The metabolites formed via the major metabolic pathways of haloperidol in liver microsomes, N -dealkylation and ring oxidation to the pyridinium species, were produced by electrochemical oxidation and characterized by ultra-performance liquid chromatography/electrospray ionization mass spectrometry (UPLC/ESI-MS). Liver microsomal incubations and electrochemical oxidation in the presence of potassium cyanide (KCN) resulted in two diastereomeric cyano adducts, proposed to be generated from trapping of the endocyclic iminium species of haloperidol. Electrochemical oxidation of haloperidol in the presence of KCN gave a third isomeric cyano adduct, resulting from trapping of the exocyclic iminium species of haloperidol. In the electrochemical experiments, addition of KCN almost completely blocked the formation of the major oxidation products, namely the N -dealkylated products, the pyridinium species and a putative lactam. This major shift in product formation by electrochemical oxidation was not observed for the liver microsomal incubations where the N -dealkylation and the pyridinium species were the major metabolites also in the presence of KCN. The previously not observed dihydropyridinium species of haloperidol was detected in the samples, both from electrochemical oxidation and the liver microsomal incubations, in the presence of KCN. The presence of the dihydropyridinium species and the absence of the corresponding cyano adduct lead to the speculation that an unstable cyano adduct was formed, but that cyanide was eliminated to regenerate the stable conjugated system. The formation of the exocyclic cyano adduct in the electrochemical experiments but not in the liver microsomal incubations suggests that the exocyclic iminium intermediate, obligatory in the electrochemically mediated N -dealkylation, may not be formed in the P450-catalyzed reaction. Copyright © 2010 John Wiley & Sons, Ltd. [source] Rapid detection and characterization of reactive drug metabolites in vitro using several isotope-labeled trapping agents and ultra-performance liquid chromatography/time-of-flight mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 6 2009Timo Rousu Reactive metabolites are believed to be one of the main reasons for unexpected drug-induced toxicity issues, by forming covalent adducts with cell proteins or DNA. Due to their high reactivity and short lifespan they are not directly detected by traditional analytical methods, but are most traditionally analyzed by liquid chromatography/tandem mass spectrometry (LC/MS/MS) after chemical trapping with nucleophilic agents such as glutathione. Here, a simple but very efficient assay was built up for screening reactive drug metabolites, utilizing stable isotope labeled glutathione, potassium cyanide and semicarbazide as trapping agents and highly sensitive ultra-performance liquid chromatography/time-of-flight mass spectrometry (UPLC/TOFMS) as an analytical tool. A group of twelve structurally different compounds was used as a test set, and a large number of trapped metabolites were detected for most of them, including many conjugates not reported previously. Glutathione-trapped metabolites were detected for nine of the twelve test compounds, whereas cyanide-trapped metabolites were found for eight and semicarbazide-trapped for three test compounds. The high mass accuracy of TOFMS provided unambiguous identification of change in molecular formula by formation of a reactive metabolite. In addition, use of a mass defect filter was found to be a usable tool when mining the trapped conjugates from the acquired data. The approach was shown to provide superior detection sensitivity in comparison to traditional methods based on neutral loss or precursor ion scanning with a triple quadrupole mass spectrometer, and clearly more efficient detection and characterization of reactive drug metabolites with a simpler test setup. Copyright © 2009 John Wiley & Sons, Ltd. [source] Mitochondrial and peroxisomal ,-oxidation capacities in various tissues from Atlantic salmon Salmo salarAQUACULTURE NUTRITION, Issue 2 2000FrØyland In order to investigate the capacities of different tissues to oxidize fatty acids, total ,-oxidation (mitochondrial and peroxisomal) of [1,14C]palmitoyl-CoA was determined in liver and red- and white muscle from adult and juvenile Atlantic salmon Salmo salar. By including potassium cyanide (KCN) in the assay medium, it was possible to differentiate between mitochondrial and peroxisomal ,-oxidation capacities. Mitochondrial ,-oxidation dominated in all tissues except in livers from juvenile fish where the peroxisomal ,-oxidation dominated. In general, the red muscle possesses the highest fatty acid oxidation capacity, however, by taking into consideration the fact that white muscle occupies approximately 60% of the total body weight, this study demonstrates that the white muscle is an important tissue in the overall fatty acid catabolism. [source] The relationship between cell membrane damage and lipid peroxidation under the condition of hypoxia-reoxygenation: analysis of the mechanism using antioxidants and electron transport inhibitorsCELL BIOCHEMISTRY AND FUNCTION, Issue 6 2009Daisuke Yajima Abstract We consecutively observed lipid peroxidation and cell membrane damage under the condition of hypoxia-reoxygenation (H/R) in cells and analyzed their mechanisms by using electron transport inhibitors and an antioxidant. In H/R experiments, lipid peroxidation and cell membrane damage were observed during the hypoxia phase. In the reoxygenation phase, lipid peroxidation stopped, while cell membrane damage did not. An antioxidant, n-acetylcystein (NAC), and potassium cyanide (KCN) inhibited lipid peroxidation and cell membrane damage, while rotenone did not inhibit either of them. Although antimycin A did not inhibit lipid peroxidation, it inhibited cell membrane damage during the hypoxia phase but not during the reoxygenation phase. These results suggested that lipid peroxidation can affect cell membrane damage as a trigger during the hypoxia phase and the generation of oxidative stress can vary depending on the inhibition locations in the electron transport system. Copyright © 2009 John Wiley & Sons, Ltd. [source] | |||||||||||||