- New route for synthesis of fluorescent SnO2 nanoparticles for selective sensing of Fe(III) in aqueous media
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A simple new route for synthesis of fluorescent SnO2 and its application as an efficient sensing material for Fe3+ in aqueous media is reported. The fluorescent SnO2 nanoparticles were obtained by oxidation of SnCl2, which when used as reducing agent for the reduction of organic nitro compounds to corresponding amino compounds in ethanol. The SnO2 nanoparticles have been characterized on the basis of powder-XRD, IR, UV-Vis, TEM, FESEM and EDX analysis and found that this material is highly fluorescent in aqueous media. Detail study revealed that this material functions as a selective probe for Fe3+ out of a large number of metal ions used. The oxygen vacancies (defects) generated on the surface of the SnO2 during synthesis, are the source of emission due to recombination of electrons with the photo-excited hole in the valance bond. The quenching of emission intensity in presence of Fe3+ is due to the nonradiative recombination of electrons and holes at the surface. This material is used for estimation of Fe3+ in real samples such as drinking water, tap water and soil.
- Vyas, Gaurav,Kumar, Anshu,Bhatt, Madhuri,Bhatt, Shreya,Paul, Parimal
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Read Online
- Hydroxylation of aromatic amines with dioxygen in photooxidation sensitized by substituted phthalocyanines
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Photooxidation of aniline and its methyl and chloro derivatives with dioxygen sensitized by substituted zinc (PcZn) and palladium (PcPd) phthalocyanines in solution and on the carrier surface upon visible light irradiation affords selectively the corresponding p-aminophenols. Active and the most stable PcPd derivative adsorbed on Amberlite XAD 7HP provides conversion of 2,6-dimethylaniline with selectivity over 90% without the loss of sensitizer activity at least in 8 repeated cycles, the overall turnover number of the sensitizer being greater than 25,000.
- Fedorova, Tatyana M.,Derkacheva, Valentina M.,Shevchenko, Ekaterina N.,Luk'yanets, Evgeny A.,Bordaev, Eduard B.,Kaliya, Oleg L.
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- A capping agent dissolution method for the synthesis of metal nanosponges and their catalytic activity towards nitroarene reduction under mild conditions
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We report a general strategy for the synthesis of metal nanosponges (M = Ag, Au, Pt, Pd, and Cu) using a capping agent dissolution method where addition of water to the M@BNHx nanocomposite affords the metal nanosponges. The B-H bond of the BNHx polymer gets hydrolysed upon addition of water and produces hydrogen gas bubbles which act as dynamic templates leading to the formation of nanosponges. The rate of B-H bond hydrolysis has a direct impact on the final nanostructure of the materials. The metal nanosponges were characterized using powder XRD, electron microscopy, XPS, and BET surface area analyzer techniques. The porous structure of these nanosponges offers a large number of accessible surface sites for catalytic reactions. The catalytic activity of these metal nanosponges has been demonstrated for the reduction of 4-nitrophenol where palladium exhibits the highest catalytic activity (k = 0.314 min?1). The catalytic activity of palladium nanosponge was verified for the tandem dehydrogenation of ammonia borane and the hydrogenation of nitroarenes to arylamines in methanol at room temperature. The reduction of various substituted nitroarenes was proven to be functional group tolerant except for a few halogenated nitroarenes (X = Br and I) and >99% conversion was noted within 30-60 min with high turnover frequencies (TOF) at low catalyst loading (0.1 mol%). The catalyst could be easily separated out from the reaction mixture via centrifugation and was recyclable over several cycles, retaining its porous structure.
- Ghosh, Sourav,Jagirdar, Balaji R.
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p. 17401 - 17411
(2019/01/03)
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- The Diels-Alder reactions of para-benzoquinone nitrogen-derivatives: An experimental and theoretical study
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An experimental and theoretical study of the comparative reactivity and selectivity of the Diels-Alder reactions of para-benzoquinones and three nitrogen derivatives have been performed. The mono-oximes derivatives do not react under the tested reaction conditions, whereas the tosylated mono-oximes react slowly. However, the mono N-tosyl imines show excellent reactivity, and superior to the parent parabenzoquinones. DFT calculations support these experimental results.
- Uliana, Marciana P.,Servilha, Bruno M.,Alexopoulos, Olga,De Oliveira, Kleber T.,Tormena, Cláudio F.,Ferreira, Marco A.B.,Brocksom, Timothy J.
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p. 6963 - 6973
(2015/11/09)
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- Monodispersed Ag nanoparticles as catalyst: Preparation based on crystalline supramolecular hybrid of decamethylcucurbit[5]uril and silver ions
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Monodispersed silver nanoparticles (Ag0 NPs) have been first prepared on the basis of a postsynthesis via mild reduction from a new crystalline supramolecular hybrid solid assembled from Ag+ ions and decamethylcucurbit[5]uril (Me10CB[5]). Uniform growth of nearly spherical Ag0 NPs with an average size of ca. 4.4 nm was observed on the organic Me10CB[5] support to form Ag@Me10CB[5] composite material. The as-synthesized composite material was characterized by a range of physical measurements (PXRD, TGA, XPS, ICP, TEM, etc.) and was further exploited as a heterogeneous catalyst for the reduction of various nitrophenols in the presence of NaBH4. The kinetics of the reduction process was monitored under various experimental conditions. The Ag@Me10CB[5] composite material showed excellent catalytic performance over the reduction reactions and remained active after several consecutive cycles.
- Li, Hong-Fang,Lue, Jian,Lin, Jing-Xiang,Cao, Rong
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p. 5692 - 5697
(2014/06/23)
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- COMPOUNDS AND METHODS FOR MODULATING ACTIVITY OF CALCIUM RELEASE CHANNELS
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The present teachings provide compounds of Formulae I and II: and and pharmaceutically acceptable salts, hydrates, complexes, esters, and prodrugs thereof, wherein R1, R1', R2, R2', R3, R3', and X are as defined herein. The present teachings also provide methods of making the compounds of formulae I and II, and methods of treating RyR-associated conditions, disorders, and diseases that include administering a therapeutically effective amount of a compound of formula I or II to a subject in need thereof. In addition, the present teachings relate to methods of reducing the open probability of a ryanodine receptor, and methods of reducing Ca2+ release across a ryanodine receptor (e.g., into the cytoplasm of a cell), by contacting a compound of formula I or II with a ryanodine receptor.
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Page/Page column 43
(2010/11/04)
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- Bisacetamide hydrochloride: A chemoselective and inexpensive N-acetylating reagent for aminophenols
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A facile and chemoselective acetylation of aminophenols using bisacetamide hydrochloride under conventional heating and microwave irradiation has been developed. Also, a rapid method for the microwave-assisted preparation of aminophenols is described herein.
- Peng, Yanqing,Song, Gonghua,Ding, Fang
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p. 2021 - 2023
(2007/10/03)
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- 1,3-Dihydroxybenzene derivatives and colorants containing said compounds
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1,3-Dihydroxybenzene derivatives of general formula (I) or (Ia) or physiologically tolerated, water-soluble thereof wherein R′1 denotes substituted pyridyl group, a pyrimidyl group, a group of formula (IIa) or (IIIa) and the dyeing agents for keratin fibers containing these compounds.
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- One step hair coloring compositions using salts
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A hair coloring composition comprising the following two compositions which are mixed just prior to application to the hair: (a) a composition comprising a water-soluble peroxygen oxidizing agent; and (b) a composition comprising one or more oxidative hair coloring agents selected from the group consisting of an aromatic diamine, an amino phenol, a naphthol, a polyhydric phenol, a catechol and mixtures thereof; wherein the composition comprising one or more oxidative hair coloring agents further comprises al least one water soluble carbonate releasing salts; and optionally a water soluble ammonium salt, is described.
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- Transition metal complexes as dye forming catalysts in hair coloring compositions
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A hair coloring composition comprising a first composition which comprises: (a) a dye forming transition metal salt or complex; which is first applied to the hair; and a second composition which comprises the following two compositions which are mixed just prior to application to the hair: (a) a composition comprising a water-soluble peroxygen oxidizing agent; and (b) a composition comprising one or more oxidative hair coloring agents selected from the group consisting of an aromatic diamine, an aminophenol, a polyhydric phenol a catechol and mixtures thereof.
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- Hair colouring and conditioning compositions
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A hair colouring and conditioning composition comprising: (a) a hair colouring agent; and (b) a hair conditioning agent; wherein the composition provides an Average Combing Index Value of greater than 1.2 as measured by the Combing Technical Test Method. The products can provide excellent hair colouring together with excellent conditioning, reduced hair damage, brittleness and dryness, and is convenient and easy to use.
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- Enhanced color deposition for hair with sequestering agents
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Hair coloring compositions which comprise: (A) non-nitrogenous chelating agents from the group consisting of polyphosphate; phosphonates; hydroxycarboxylates; polyacrylates; zeolite; and mixtures thereof; (B) an oxidative dye primary intermediate; and (C) an oxidative dye coupler; (D) and water are described. The present invention also relates to a method for coloring hair which comprises contacting said hair with a hair coloring composition as described above.
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- Hair conditioning compositions and their use in hair colouring compositions
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The present invention relates to a hair care composition comprising a aminofunctional polysiloxane having a specified average effective particle size which provides improved durable conditioning particularly when utilised in conjunction with a hair colouring composition.
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- Means and method for dying keratinic fibers
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Composition for coloring keratin fibers based on a developer-coupler combination characterized in that it contains as the coupler 3-(2,4-diaminophenoxy)-1-propanol and as the developer a p-phenylenediamine derivative monosubstituted on the benzene ring and having general formula (I) ?and/or a 4,5-diamino-1H-pyrazole derivative of general formula (II) ?and/or a p-aminophenol derivative of general formula (III) ?as well as a method for the oxidative coloring of hair, and the use of said composition.
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- HAIR COLORING COMPOSITIONS
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A hair coloring composition comprising: (a) from about 0.0003 moles (per 100 g of composition) to less than about 0.09 moles (per 100 g of composition) of an inorganic peroxygen oxidizing agent; and (b) an oxidative hair coloring agent; wherein the pH of each of (a) and (b) is in the range of from about 1 to about 6 and wherein the combined mixture of (a) and (b) has a pH in the range of from about 1 to about 6. The products can provide excellent hair coloring and in-use efficacy benefits including excellent initial color and good wash fastness in combination with reduced hair damage at low pH.
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- HAIR COLORING COMPOSITIONS
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A hair coloring composition comprising: (a) a preformed organic peroxyacid oxidising agent; and (b) an oxidative hair coloring agent; wherein the pH of each of components (a) and (b) is in the range of from about pH 1 to less than about pH 7 and wherein the pH of the composition is in the range of from about pH 1 to less than about pH 7. The products can provide excellent hair coloring and in-use efficacy benefits including excellent initial color and good wash fastness in combination with reduced hair damage at low pH.
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- 1,4-diazacycloheptane derivatives and their use in hair oxidation dyes
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A 1,4-diazacycloheptane derivative and an oxidative hair colorant containing the derivative as a primary intermediate is presented. The 1,4-diazacycloheptane derivative is of the formula: STR1 where R1, R2, R3 and R4 independently of one another represent hydrogen, a C1-4 alkyl or hydroxyalkyl group or a C2-4, dihydroxyalkyl group, X and Y independently of one another represent hydrogen, chlorine, fluorine, a C1-4 alkyl, hydroxyalkyl, aminoakyl or alkoxy group, a C2-4 dihydroxyalkyl group or an allyl group and R5 and R6 independently of one another represent hydrogen or a C1-4 alkyl group. Natural color tones can be obtained in keratin fibers with oxidative hair colorants containing the 1,4-diazacycloheptane derivative, without the use of additional primary intermediates.
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- Composition for the oxidation dyeing of keratinous fibres comprising a para-phenylenediamine, a meta-phenylenediamine and a para-aminophenol or a meta-aminophenol, and dyeing process
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An oxidation dyeing composition for keratinous fibres, in particular human keratinous fibres such as hair, of the type comprising a medium suitable for dyeing, the medium containing at least one first para-phenylenediamine oxidation dye precursor containing a primary, secondary or tertiary amine function; at least one first meta-phenylenediamine coupling agent; and either at least one second para-aminophenol oxidation dye precursor or at least one second meta-aminophenol coupling agent; or the acid addition salts thereof. The use of this composition for dyeing keratinous fibres, in particular human keratinous fibres such as hair.
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- Hair dye compositions containing 3-substituted-4-aminophenols and 2-substituted-1-naphthols
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A 2-Substituted-1-naphthol of the formula: STR1 wherein R1 is C1 -C6 alkyl or monohydroxy C1 -C6 alkyl couples with a primary intermediate of the formula: STR2 wherein R is C1 -C6 alkyl or monohydroxy C1 -C6 alkyl to produce an oxidative dye.
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- Methods for dyeing keratinous fibers with compositions which contain aminoindole couplers, oxidation dye precursors, and oxidizing agents at acid pHs
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A method for dyeing keratin fibers, wherein a composition is applied to said fibers which contains, in a suitable dyeing medium, at least one coupler having formula (I) STR1 wherein R1 is hydrogen or alkyl; R2 and R3 are hydrogen, alkyl, COOR', where R' is alkyl or hydrogen; R4 is hydrogen, hydroxyalkyl, alkyl, polyhydroxyalkyl or acetyl or aminoalkyl wherein the amine may be mono- or disubstituted by alkyl; Z1 and Z2 are hydrogen, alkyl, hydroxy, halogen, alkoxy or a salt thereof; at least one precursor of an oxidation hair dye; and at least one oxidizing agent, the pH of the composition applied to the fibers being less than 7.
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- Halide ion trapping of nitrenium ions formed in the Bamberger rearrangement of N-arylhydroxylamines. Lifetime of the parent phenylnitrenium ion in water
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The data of p-aminophenol, the product of Bamberger rearrangement, Were analyzed by a mechanism involving rate-limiting formation of the appropriate arylnitrenium ion followed by product-determining steps in involving trapping by the solvent or by the added halide. The possibility that a portion of the halide-trapped products were derived from a pre-association mechanism was also include. Kinetic analyses then produced kBr:kw and kCl:kw ratios for two limiting cases, one involving pre-association with an equilibrium constant Kas = 0.3, and one ignoring pre-association. From an azide:water ratio (kAz:kw) previously determined for the 2,6-dimethylphenylnitrenium, kBr was concluded to lie in the range (4-5) × 109 M-1 s-1 for all of the nitrenium ions of this study. This range for kBr then led to kw values of (1-2) × 109 s-1 (2,5-Me2), (2-3) × 109 s-1 (2-Me), and (4-8) × 109 s-1 (parent and 2-Cl), where the ranges reflect uncertainties in the exact value of kBr and in the contribution from pre-association. The lifetime of the parent phenylnitrenium ion in water at one molar ionic strength is concluded to lie in the range 125-250 ps.
- Fishbein,McClelland
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p. 1321 - 1328
(2007/10/03)
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- Fiber reactive anthraquinone dyes
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The invention is that of a water soluble fiber reactive anthraquinone blue dyes. These dyes may be used to dye and print textiles and other substrates containing hydroxy and or groups in brilliant blue colors. The dyes of the invention are free of heavy metals.
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- Process for dyeing keratinous fibers with 2,4-diamino-1,3-dimethoxybenzene at an acid ph and compositions employed
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Process for dyeing keratinous fibres, especially human keratinous fibres such as the hair, characterised in that a composition containing, in a medium suitable for dyeing, at least 2,4-diamino-1,3-dimethoxybenzene as a coupler; an oxidation dye precursor; and an oxidising agent; is applied to these fibres, the pH of the composition applied to the fibres being less than 7.
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- THERMOTROPIC LIQUID CRYSTAL BEHAVIOR IN SOME AROMATIC ESTERAMIDES.
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Ester-amide analogs of p-phenylene di-p-substituted benzoates have been synthesized and the thermotropic liquid crystal properties of the two series are compared. The crystalline, smectic, and nematic phases are all more thermally stable in the ester-amides than in the diesters. In the corresponding series of 4-alkoxybenzoyl compounds, as the alkyl chain length increases the difference in nematic phase stability also increases, but the difference in smectic phase stability decreases. Introduction of a methyl substituent into the central ring reduces the stability of all three phases, and increases the sensitivity of smectic phase stability, but not of crystalline or nematic phase stability, to alkyl chain length.
- Kalyvas,McIntyre
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p. 105 - 118
(2007/10/02)
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- Kinetics and Mechanism of the Bamberger Rearrangement. Part 4. Rearrangement of Sterically Hindered Phenylhydroxylamines to 4-Aminophenols in Aqueous Sulphuric Acid Solution
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The rates of the Bamberger rearrangement of sterically hindered phenylhydroxylamines have been determined in aqueous sulphuric acid solution and the substituent effects (in particular, the steric effects) are discussed.The rate constants for phenylhydroxylamines with 2-substituents (Me, Cl, I) satisfied the Taft equation: log krel = ρ*?* - δES with ρ*-1.93 and δ-1.16.The result shows that steric hindrance of the substituents, in addition to the electron-donating effect, has an accelerating effect on the rates of the Bamberger rearrangement.The rate constants for 3-substituted 2-methylphenylhydroxylamines were generally greater than those for 5-substituted 2-methylphenylhydroxylamines.The difference was attributed to the 'buttressing effect' of neighbouring 3-substituents.This is the first example of steric acceleration of the Bamberger rearrangement.
- Sone, Takaaki,Hamamoto, Kazuhiro,Seiji, Yoshiyuki,Shinkai, Seiji,Manabe, Osamu
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p. 1596 - 1598
(2007/10/02)
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- Synthesis of 4,7-Dimethoxyindoles Bearing Substituents at the C-5 and C-6 Positions and Studies on their Demethylation Products
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Syntheses of some 4,7-dimethoxyindoles bearing methyl, amino or acetamido groups at the C-5 and C-6 positions were investigated.The presence of these substituents made possible the isolation of the corresponding 4,7-dihydroxyindole derivatives obtained by long reflux with aluminium chloride in benzene solution.
- Malesani, Giorgio,Galiano, Fabio,Ferlin, Maria Grazia,Masiero, Sergio
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p. 563 - 569
(2007/10/02)
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