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Showing papers on "Iodide published in 1989"


Journal ArticleDOI
TL;DR: Methyl fluorosulphonyldifluoroacetate, in the presence of copper(I) iodide, is used as the source of trifluoromethyl group which replaces the halogen in aryl, alkenyl, and alkyl halides as discussed by the authors.
Abstract: Methyl fluorosulphonyldifluoroacetate, in the presence of copper(I) iodide, is used as the source of trifluoromethyl group which replaces the halogen in aryl, alkenyl, and alkyl halides.

243 citations


Journal ArticleDOI
TL;DR: The response properties of a new solvent/polymeric membrane electrode with unique selectivity toward anionic salicylate are reported, and it is shown that the metal center of the metalloporphyrin is critical for selective salicyllate transport in the membrane phase.
Abstract: The response properties of a new solvent/polymeric membrane electrode with unique selectivity toward anionic salicylate are reported. The electrode is prepared by incorporating 5, 10, 15, 20-tetraphenyl(porphyrinato)tin(IV) dichloride (Sn[TPP]Cl2) into a plasticized poly(vinyl chloride) membrane. The resulting sensor exhibits an anti-Hofmeister selectivity pattern, with high specificity for salicylate over lipophilic inorganic anions (perchlorate, periodate, thiocyanate, iodide, etc.) and biological organic anions (citrate, lactate, acetate). Moderate selectivity over structural analogues of salicylate (3- and 4-hydroxybenzoate, benzoate) is also observed. Radiotracer uptake experiments using [14C]salicylate clearly show that the metal center of the metalloporphyrin is critical for selective salicylate transport in the membrane phase. Minimal response to chloride ions makes the new electrode potentially useful for estimating salicylate levels in biological samples.

195 citations


Journal ArticleDOI
TL;DR: In this article, treatment of methyl 5-acetamido with thiophenol, phenylmethanethiol, and ethanethylamine in the presence of boron trifluoride etherate gave the corresponding 2-thio-β-glycosides 3−5.

175 citations


Journal ArticleDOI
TL;DR: It is suggested that rather than specific groups in the molecule also being involved, activity at nicotinic receptors depends on interactions between a flat part of the drug containing double‐bonds, or systems of double bonds, and a planar area in the receptor, possibly tyrosine or phenylalanine residues.
Abstract: 1. Although (-)-cytisine is a rigid structure, it occurs in the crystal in two distinct but very similar conformations in which the pyridone ring is tilted relative to the charged nitrogen atom at much the same angle as the pyridine ring is in (-)-nicotine hydrogen iodide. The carbonyl group in the pyridone ring of (-)-cytisine, however, is on the side of the ring opposite to pyridine nitrogen in (-)-nicotine. 2. The pKa of (-)-lobeline HCl at 25 degrees C is 8.6 (approx), indicating that (-)-lobeline is at least 90% in the protonated form at physiological pH (7.6). It is probably the phenyl 2-keto-ethyl part of (-)-lobeline, rather than the phenyl 2-hydroxy-ethyl part, which interacts with the receptor. 3. The combination within one molecule of a charged ('onium') nitrogen atom lying out of the plane of, and some distance (4.5-6.5 A) from, an aromatic ring is common to many compounds with nicotine-like activity (e.g. nicotine, cytisine, choline phenyl ether bromide, dimethyl-phenyl-piperazinium (DMPP) iodide, coryneine iodide and m-hydroxyphenylpropyl trimethyl ammonium iodide). In some molecules the aromatic ring can be replaced by an unsaturated group, such as carbonyl (e.g. acetylcholine) or double-bonds (e.g. anatoxin). 4. Activity at nicotinic receptors appears to involve interactions between the positively charged nitrogen atom and a negatively charged group, probably close to cysteine residues 192 and 193 in the receptor. It is suggested that rather than specific groups in the molecule also being involved, activity at nicotinic receptors depends on interactions between a flat part of the drug containing double-bonds, or systems of double bonds, and a planar area in the receptor, possibly tyrosine or phenylalanine residues.

96 citations


Journal ArticleDOI
TL;DR: In the course of Compound III and Compound II conversion back to the native peroxidase, oxygen derived free radicals such as O2-, HO, and .OH are generated and the enzyme is irreversibly damaged.

83 citations


Journal ArticleDOI
TL;DR: In the presence of catalytic amounts of sodium sulfate or cuprous iodide, a variety of alkyl and aryl difluoromethyl ethers were synthesized in moderate yields by the reaction of the corresponding alcohols and phenols with fluorosulfonyldifluoroacetic acid in acetonitrile under mild conditions.

74 citations



Journal ArticleDOI
TL;DR: In this paper, a new general process of selective, homolytic alkylation of heteroaromatic bases of great synthetic interest is described, based on the reaction of alkyl iodides with hydrogen peroxide and heterocyclic compounds in DMSO, catalysed by an FE(II) salt.
Abstract: A new general process of selective, homolytic alkylation of heteroaromatic bases of great synthetic interest is described. It is based on the reaction of alkyl iodides with hydrogen peroxide and heterocyclic compounds in DMSO, catalysed by an FE(II) salt. It is shown that the iodine abstraction from the alkyl iodide by the methyl radical, generated from the solvent, is the key point of the overall process. Combined enthalpic and polar effects contribute to the high selectivity: the enthalpic factor governs the equilibria of the iodine abstraction, and the polar factor determines the reactivity toward the protonated heterocyclic ring

71 citations


Journal ArticleDOI
TL;DR: Indium(I) iodide was found to mediate in the Barbier allylation and in the Reformatsky reaction of aldehydes and ketones to give homoallylic alcohols and β-hydroxy esters, respectively, presumably via allylindium(III) diiodide as discussed by the authors.

68 citations



Journal ArticleDOI
TL;DR: A new automated method for determining inorganic iodine species in seawater as iodide- and total iodine (iodide+iodate), by using a flow-through electrode system, has been applied to the seawater samples collected from the adjacent seas of Japan and the western and central North Pacific Ocean as discussed by the authors.

Journal ArticleDOI
TL;DR: In this article, a copper SET-induced mechanism was proposed to suppress the trifluoromethyl displaced compound in the presence of a single electron transfer scavenger, p-dinitrobenzene, and free radical inhibitor, hydroquinone.
Abstract: Aryl halides are readily trifluoromethylated with fluorosulphonyldifluoromethyl iodide (1) in the presence of copper in DMF in high yield. A single electron transfer (s.e.t.) scavenger, p-dinitrobenzene, and free radical inhibitor, hydroquinone, partly suppress the reaction. Addition of 2,3-dimethylbut-2-ene to the reaction mixture gives a free radical addition-elimination product and difluorocarbene derivatives besides the trifluoromethyl displaced compound. A copper SET-induced mechanism is proposed.

Journal ArticleDOI
TL;DR: The coupling of various 5-substituted 2,4- disilyl pyrimidines with a 3,5-di-p-toluyl ribofuransyl chloride in the presence of copper (I) iodide in chloroform yields predominantly β-nucleosides (>15/1 β/α selectivity in some cases) in >90% overall yields as discussed by the authors.
Abstract: The coupling of various 5-substituted-2,4- disilyl pyrimidines with a–2-deoxy-3,5-di-p-toluyl ribofuransyl chloride in the presence of copper (I) iodide in chloroform yields predominantly β-nucleosides (>15/1 β/α selectivity in some cases) in >90% overall yields.

Journal ArticleDOI
TL;DR: Palladium-catalyzed one-pot sequential reaction of Me 3 SnC≡CSiMe 3 first with an alkenyl iodide R 1 I and secondly with another (or aryl) iodide I in the presence of newly added (Et 2 N) 3 S + Me 3 SiF 2 − affords conjugated dienynes R 1 -C-R 2 with high stereospecificity.


Journal ArticleDOI
TL;DR: The pH dependence of line width of 15N resonance of SC15N- in the presence of the enzyme has revealed that the binding of the thiocyanate to the enzyme is facilitated by protonation of an ionizable group (with pKa of 6.4), which is presumably distal histidine.
Abstract: The binding of thiocyanate to lactoperoxidase (LPO) has been investigated by 1H and 15N NMR spectroscopy. 1H NMR of LPO shows that the major broad heme methyl proton resonance at about 61 ppm is shifted upfield by addition of the thiocyanate, indicating binding of the thiocyanate to the enzyme. The pH dependence of line width of 15N resonance of SC15N- in the presence of the enzyme has revealed that the binding of the thiocyanate to the enzyme is facilitated by protonation of an ionizable group (with pKa of 6.4), which is presumably distal histidine. Dissociation constants (KD) of SC15N-/LPO, SC15N-/LPO/I-, and SC15N-/LPO/CN- equilibria have been determined by 15N T1 measurements and found to be 90 +/- 5, 173 +/- 20, and 83 +/- 6 mM, respectively. On the basis of these values of KD, it is suggested that the iodide ion inhibits the binding of the thiocyanate but cyanide ion does not. The thiocyanate is shown to bind at the same site of LPO as iodide does, but the binding is considerably weaker and is away from the ferric ion. The distance of 15N of the bound thiocyanate ion from the iron is determined to be 7.2 +/- 0.2 Amore » from the 15N T1 measurements.« less

Book ChapterDOI
TL;DR: In this case, however, the amounts of iodide which enter the thyroid cell remain large, despite transport saturation and are replaced by diffused iodide, so this subject will not be discussed here.
Abstract: The many nonsubstrate effects of iodide in the thyroid appear to be due to at least four mechanisms: 1) a possible anion effect of iodide for which the supporting data are conflicting; 2) an inhibition of organic iodine formation (the so-called Wolff-Chaikoff effect); 3) the iodination of critical enzymes in the thyroid gland; and 4) the inhibition of cellular processes by iodinated products such as oxidized iodine itself, or an oxidation reaction involving iodine. The separation into these categories is not firm, but circumstantial evidence suggests that the mechanisms are different. In addition, high levels of iodide will saturate the iodide pump (Ki ≈3×10−5M) (1). In this case, however, the amounts of iodide which enter the thyroid cell remain large, despite transport saturation and are replaced by diffused iodide. Hence this subject will not be discussed here.

Journal ArticleDOI
TL;DR: In this paper, a new solvent/polymeric-membrane electrode which exhibits significant potentiometric response toward sulfite ion in the 1 X 1O-6-1 X 10m3 M range is described.

Journal ArticleDOI
TL;DR: In this article, a thiocyanate-selective solvent-polymeric membrane electrode was proposed for detection of thioxyanate in 22 human saliva samples with good correlation to a classical colorimetric method (r = 0.981).
Abstract: The response properties of a new thiocyanate-selective solvent-polymeric membrane electrode are reported. The membrane contains (5,10,15,20-tetrakis(2,4,6-triphenylphenyl)porphyrinato)manganese(III) chloride (Mn[TPPP]CI) in a plasticized polyvinyl chloride matrix. The electrode deviates from the Hofmeister selectivity pattern by responding to thiocyanate preferentially over inorganic anions (perchlorate, chloride, iodide, and bromide) and several organic anions often present in biological samples (ascorbate, citrate, urate, and salicylate). The performance of this electrode as an ion-selective detector in a low-dispersion, flow-injection system is also evaluated. While selectivity in such a nonequilibrium flow arrangement is found to be somewhat different than that observed under equilibrium conditions, the electrode's response and selectivity is still adequate to allow for measurement of thiocyanate in biological samples. This application is demonstrated via the flow-injection analysis (FIA) detection of thiocyanate in 22 human saliva samples with good correlation to a classical colorimetric method (r = 0.981).


Journal ArticleDOI
TL;DR: In this article, the x-ray structure of cyanoethylzinc iodide is also reported, and the reaction of the corresponding organic halides with zinc and subsequent transmetalation with CuCN · 2 LiCl.

Journal ArticleDOI
TL;DR: It is concluded that iodide exerts its inhibitory action on the growth of thyroid cells at multiple loci related to both the cAMP-dependent andcAMP-independent pathways of mitogenic regulation.
Abstract: We have explored the mechanisms whereby iodine inhibits thyroid growth using as models both the FRTL5 line of rat thyroid follicular cells that require TSH for growth and the M12 line of mutant cells that grow in the absence of TSH. Between 0.01-1.0 mM, NaI produced a dose-dependent inhibition of TSH stimulation of [3H]thymidine incorporation and replication in FRTL5 cells as well as spontaneous growth in M12 cells. Iodide also inhibited the cAMP-dependent growth of FRTL5 cells induced by forskolin and (Bu)2cAMP, as well as the cAMP-independent mitogenesis induced by insulin-like growth factor-I. The effect of iodide to inhibit both TSH- and insulin-like growth factor-I-stimulated growth in FRTL5 cells was abolished by concomitant culture with methimazole, and no iodide inhibition of growth was observed in L6 myoblasts and BRL 30E hepatocytes. Exposure of cells to iodide under conditions that resulted in inhibition of TSH-stimulated growth did not significantly alter the ability of TSH to increase the intracellular cAMP concentration, nor did iodide alter two responses to TSH in FRTL5 cells that depend upon an increase in cAMP concentration: down-regulation of TSH receptor and cytoskeletal reorganization. We conclude that iodide exerts its inhibitory action on the growth of thyroid cells at multiple loci related to both the cAMP-dependent and cAMP-independent pathways of mitogenic regulation.

Journal ArticleDOI
TL;DR: In this article, the synthesis and characterization of deep-colored squarylium dyes was studied with respect to the development of media in optical recording systems, and the structures of the dyes were also discussed on the basis of IR and ESCA analyses.

Journal ArticleDOI
TL;DR: Chemical experiments demonstrate that osmium-potassium iodide (Os-KI) mixture reacts rapidly with several naturally occurring plant phenols, developing black solutions from which black solids precipitate.
Abstract: A simple procedure to stain phenols in plant tissues is described. Postfixation with an aqueous solution prepared by mixing 2 cc of 2% osmium tetroxide and 8 cc of 3% potassium iodide yields brilliant visualization of phenol-containing vacuoles in different tissues of plants (e.g., coffee, oak, tobacco and spruce) bearing high concentration of phenolic compounds. Areas bearing phenols become dark gray to black. Chemical experiments demonstrate that osmium-potassium iodide (Os-KI) mixture reacts rapidly with several naturally occurring plant phenols, developing black solutions from which black solids precipitate. Phenols containing omicron-dihydroxy groups react with Os-KI solution more rapidly than other structurally different phenols. Therefore, omicron-dihydroxy units in an aromatic ring seem to function as primary sites of reactivity with the osmium-iodide complexes.

Journal ArticleDOI
TL;DR: It was found that the presence of cyanide and resorcinol did not have any effect on the binding of thiocyanate, indicating that the binding site of the thiOCyanate ion is located away from the ferric center as well as from the aromatic donor binding site.


Journal ArticleDOI
TL;DR: The bromide and iodide contents of rainwater, drinking water, river water, seawater, oil brine, common salt, cow milk, and human blood serum were determined.
Abstract: Oxidation of bromide and iodide ions in acidic solutions in the presence of acetone forms the corresponding acetone derivatives. Iodate was reduced with thiosulfate prior to the determination. After extraction with benzene the bromo- and iodoacetone were measured by gas chromatography using electron capture detection. The bromide and iodide contents of rainwater, drinking water, river water, seawater, oil brine, common salt, cow milk, and human blood serum were determined. The relative standard deviations for bromide at 10(-7) M and for iodide at 10(-8) M concentration were 1.9% and 3.0%, respectively, using a 10-mL sample for the determination without preconcentration.

Journal ArticleDOI
TL;DR: The oxazolinium iodide 9 reacts with phenylmagnesium bromide to give 4,6-diphenylthieno[2,3-c]furan (5b) as mentioned in this paper.
Abstract: Das Oxazoliniumiodid 9 reagiert mit Phenylmagnesiumbromid zu 4,6-Diphenylthieno[2,3-c]furan (5b). Es werden einige Reaktionen mit 5b, die Rontgenstrukturanalyse, Lumineszenzspektren und theoretische Untersuchungen beschrieben. 4,6-Diphenylthieno[2,3-c]furan The oxazolinium iodide 9 reacts with phenylmagnesium bromide to give 4,6-diphenylthieno[2,3-c]furan (5b). Some reactions, the X-ray structure analysis, luminescence spectra, and theoretical investigations are described.

Journal ArticleDOI
TL;DR: In this paper, a reagent for amination of aryl Grignard reagents in ether-toluene in the presence of a catalytic amount of copper (I) iodide or magnesium chloride was proposed.
Abstract: Acetone oxime O-mesitylenesulphonate is shown to be a convenient reagent for amination of aryl Grignard reagents in ether-toluene in the presence of a catalytic amount of copper (I) iodide or magnesium chloride.

Journal ArticleDOI
TL;DR: The first stable and isolable alkanetellurenyl halides were obtained by halogenolysis of bis[tris-(trimethylsilyl)methyl] ditelluride with SO2Cl2, Br2, and I2, respectively as mentioned in this paper.
Abstract: Tris (trimethylsilyl)methanetellurenyl Halides (Me3Si)3 CTex (X = Cl, Br, I): Synthesis of Stable Alkanetellurenyl Halides The first stable and isolable alkanetellurenyl halides, tris(trimethylsilyl)methanetellurenyl chloride, bromide, and iodide (1a–c) are obtained quantitatively by halogenolysis of bis[tris-(trimethylsilyl)methyl] ditelluride with SO2Cl2, Br2, and I2, respectively. Their synthetic potential is examplified by transformation to methyl tris(trimethylsilyl)methyl telluride (2) and phenyl tris(trimethylsilyl)methyl telluride (3).