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Corresponding Alcohols (corresponding + alcohol)
Selected AbstractsEncapsulation and release of a fluorescent probe, khusimyl dansylate, obtained from vetiver oil by complex coacervationFLAVOUR AND FRAGRANCE JOURNAL, Issue 1 2008A. S. Prata Abstract The essential oil of vetiver [Vetiveria zizanoides (L.) Nash ex. Small] is widely used in the perfume industry, owing to its pleasant, long-lasting, woody aroma. If this substance can be encapsulated in microparticles so that its release can be controlled, the effective duration of its properties should be extended for a much longer period of time. The present study was thus designed to investigate the encapsulation of this vetiver essential oil in microparticles. Since the detection of the effective release of such a complex mixture from these microparticles into the receiving medium can be problematic, an identifiable probe can be released with it to facilitate evaluation of the progression of the release process. Zizanoic acid is one of the compounds found in vetiver oil which depreciates its sensorial quality. This acid was thus extracted and reduced to the corresponding alcohol, khusimol, which was combined with dansyl chloride to form a fluorescent ester, khusimyl dansylate (KD). The vetiver oil and the fluorescent probe were then encapsulated (100:1) in microparticles produced by the complex coacervation of gum Arabic and gelatin. The microparticles showed spherical shape, multinuclear distribution of the core material and high encapsulation efficiency (95%). Two versions of these microparticles, moist and freeze-dried ones, were tested for the release of the KD into an ethanol medium. The moist particles released the whole KD after 5 h, although only 80% of the fluorescent probe was released with the freeze-dried microparticles at that time, probably due to the constriction caused by freeze-drying. The release of the components of vetiver oil, under the same experimental conditions, was followed, in parallel, by gas chromatography and the results obtained were compared and discussed. Copyright © 2007 John Wiley & Sons, Ltd. [source] Biotransformation of 4-Hydroxybenzen Derivatives by Hairy Root Cultures of Polygonum multiflorum Thunb.JOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 2 2007Chun-Yan Yan Abstract The biotransformation of four 4-hydroxybenzen derivatives (1,4-benzenediol (compound 1), 4-hydroxybenzaldehyde (compound 2), 4-hydroxybenzyl alcohol (compound 3) and 4-hydroxybenzoic acid (compound 4)) by the hairy root cultures of Polygonum multiflorum Thunb. as a new biocatalyst was investigated. It was found that the substrates were transformed to their corresponding glucosides, 4-hydroxyphenyl ,- D -glucopyranoside (arbutin, compound 1a), 4-hydroxymethylphenyl ,- D -glucopyranoside (gastrodin, compounds 2a, 3a) and 4-carboxyphenyl ,- D -glucopyranoside (compound 4a), respectively. In the meantime, the hairy roots of P. multiflorum were able to stereoselectively and regioselectively glucosylate phenolic hydroxyl groups of compounds 1,4, but the cultures could not glucosylate the aldehyde group of compound 2 or the benzylic hydroxyl group of compound 3, and no glucosyl esterification of carboxyl groups of compound 4 was detected. On the other hand, the result also showed that the hairy roots of P. multiflorum were able to reduce the 4-hydroxybenzaldehyde to its corresponding alcohol. This is the first report that substrate 4 has been converted into its ,- D -glucopyranoside by a plant biotransformation system. [source] Studies on the metabolism and toxicological detection of the designer drug 2,5-dimethoxy-4-methyl-,- phenethylamine (2C-D) in rat urine using gas chromatographic/mass spectrometric techniquesJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 11 2006Denis S. Theobald Abstract The phenethylamine-derived designer drug 2,5-dimethoxy-4-methyl-,-phenethylamine (2C-D) was found to be metabolized in rats by O -demethylation at position 2 or 5 followed by N -acetylation or by deamination with oxidation to the corresponding acids or reduction to the corresponding alcohol. Furthermore, 2C-D was hydroxylated at the methyl group or deaminated followed by reduction to the corresponding alcohol or by oxidation to the corresponding acid. Most of the metabolites were excreted in conjugated form. The authors' systematic toxicological analysis (STA) procedure using full-scan GC/MS allowed the detection of an intake of a dose of 2C-D in rat urine that corresponds to a common drug user's dose. Assuming similar metabolism, the described STA procedure should be suitable for proof of an intake of 2C-D in human urine. Copyright © 2006 John Wiley & Sons, Ltd. [source] Designer drug 2,4,5-trimethoxyamphetamine (TMA-2): Studies on its metabolism and toxicological detection in rat urine using gas chromatographic/mass spectrometric techniquesJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 9 2006Andreas H. Ewald Abstract Studies are described on the metabolism and the toxicological detection of the amphetamine-derived designer drug 2,4,5-trimethoxyamphetamine (TMA-2) in rat urine using gas chromatographic/mass spectrometric (GC/MS) techniques. The identified metabolites indicated that TMA-2 was metabolized by oxidative deamination to the corresponding ketone followed by reduction to the corresponding alcohol, O -demethylation followed by oxidative deamination, and finally O,O -bis-demethylation. All metabolites carrying hydroxy groups were found to be partly excreted in urine as glucuronides and/or sulfates. The authors' systematic toxicological analysis (STA) procedure using full-scan GC/MS after acid hydrolysis, liquid-liquid extraction, and microwave-assisted acetylation allowed the detection, in rat urine, of an intake of TMA-2 that corresponds to a common drug users' dose. Assuming similar metabolism, the described STA procedure in human urine should be suitable as proof of an intake of TMA-2. Copyright © 2006 John Wiley & Sons, Ltd. [source] New designer drug, 2,5-dimethoxy-4-propylthio-,-phenethylamine (2C-T-7): studies on its metabolism and toxicological detection in rat urine using gas chromatography/mass spectrometry,JOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 1 2005Denis S. Theobald Abstract Studies are described on the metabolism and toxicological analysis of the phenethylamine-derived designer drug 2,5-dimethoxy-4-propylthio-,-phenethylamine (2C-T-7) in rat urine using gas chromatography/mass spectrometry (GC/MS). The identified metabolites indicated that 2C-T-7 was metabolized by hydroxylation of the propyl side chain followed by N -acetylation and sulfoxidation and also by deamination followed by oxidation to the corresponding acid or by reduction to the corresponding alcohol. To a minor extent, 2C-T-7 was also metabolized by S -dealkylation followed by N -acetylation, S -methylation and sulfoxidation. The authors' systematic toxicological analysis (STA) procedure using full-scan GC/MS after acid hydrolysis, liquid,liquid extraction microwave-assisted acetylation allowed the detection of an intake of a dose of 2C-T-7 in rat urine that corresponds to a common drug users' dose. Assuming similar metabolism, the described STA procedure should be suitable for proof of an intake of 2C-T-7 in human urine. Copyright © 2005 John Wiley & Sons, Ltd. [source] Characterization of cinnamyl alcohol dehydrogenase of Helicobacter pyloriFEBS JOURNAL, Issue 5 2005An aldehyde dismutating enzyme Cinnamyl alcohol dehydrogenases (CAD; 1.1.1.195) catalyse the reversible conversion of p -hydroxycinnamaldehydes to their corresponding alcohols, leading to the biosynthesis of lignin in plants. Outside of plants their role is less defined. The gene for cinnamyl alcohol dehydrogenase from Helicobacter pylori (HpCAD) was cloned in Escherichia coli and the recombinant enzyme characterized for substrate specificity. The enzyme is a monomer of 42.5 kDa found predominantly in the cytosol of the bacterium. It is specific for NADP(H) as cofactor and has a broad substrate specificity for alcohol and aldehyde substrates. Its substrate specificity is similar to the well-characterized plant enzymes. High substrate inhibition was observed and a mechanism of competitive inhibition proposed. The enzyme was found to be capable of catalysing the dismutation of benzaldehyde to benzyl alcohol and benzoic acid. This dismutation reaction has not been shown previously for this class of alcohol dehydrogenase and provides the bacterium with a means of reducing aldehyde concentration within the cell. [source] Enantioselective Copper-Catalysed Allylic Alkylation of Cinnamyl Chlorides by Grignard Reagents using Chiral Phosphine-Phosphite LigandsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2010Wibke Lölsberg Abstract The copper(I)-catalysed SN2,-type allylic substitution of E -3-aryl-allyl chlorides (cinnamyl chlorides) using Grignard reagents represents a powerful method for the synthesis of compounds carrying a benzylic stereocentre. By screening a small library of modular chiral phosphine-phosphite ligands a new copper(I)-based catalyst system was identified which allows the performance of such reactions with exceptional high degrees of regio- and enantioselectivity. Best results were obtained using TADDOL-derived ligands (3,mol%), copper(I) bromide,dimethyl sulfide (CuBr,SMe2) (2.5,mol%) and methyl tert -butyl ether (MTBE) as a solvent. Various (1-alkyl-allyl)benzene derivatives were prepared with up to 99% ee (GC) in isolated yields of up to 99%. In most cases the product contained less than 3% of the linear regioisomer (except for ortho -substituted substrates). Both electron-rich and electron-deficient cinnamyl chlorides were successfully employed. The absolute configuration of the products was assigned by comparison of experimental and calculated CD spectra. The substrates were prepared from the corresponding alcohols by reaction with thionyl chloride. Initially formed mixtures of regioisomeric allylic chlorides were homogenised by treatment with CuBr,SMe2 (2.5,mol%) in the presence of triphenyl phosphine (PPh3) (3,mol%) in MTBE at low temperature to give the pure linear isomers. In reactions with methylmagnesium bromide (MeMgBr) an ortho -diphenylphosphanyl-arylphosphite ligand with an additional phenyl substituent in ortho, -position at the aryl backbone proved to be superior. In contrast, best results were obtained in the case of higher alkyl Grignard reagents (such as ethyl-, n -butyl-, isopropyl-, and 3-butenylmagnesium bromides) with a related ligand carrying an isopropyl substituent in ortho, -position. The method was tested on a multi-mmol scale and is suited for application in natural product synthesis. [source] A Homogeneous Catalyst for Reduction of Optically Active Esters to the Corresponding Chiral Alcohols without Loss of Optical PuritiesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1 2010Wataru Kuriyama Abstract A ruthenium complex was found to catalyze the hydrogen reduction of esters under mild and neutral conditions. A variety of optically active esters can be reduced to the corresponding alcohols in excellent yield without loss of their optical purity or causing undesirable side reactions. Hydrogen reduction needs such simple operations , reaction, concentration, and purification , that the violent quench step and extraction step, which accompany conventional sodium borohydride or lithium aluminum hydride reduction, can be omitted. [source] Novel Scorpionate and Pyrazole Dioxovanadium Complexes, Catalysts for Carboxylation and Peroxidative Oxidation of AlkanesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1 2010Telma F. Abstract The dioxovanadium(V) complexes [VO2(3,5-Me2Hpz)3][BF4] (1) (pz=pyrazolyl), [VO2{SO3C(pz)3}] (2), [VO2{HB(3,5-Me2pz)3}] (3) and [VO2{HC(pz)3}][BF4] (4), bearing pyrazole or scorpionate ligands, were obtained by reaction of triethyl vanadate [VO(OEt)3] with hydrotris(3,5-dimethyl-1-pyrazolyl)methane [HC(3,5-Me2pz)3] or 3,5-dimethylpyrazole (3,5-Me2Hpz; 1), lithium tris(1-pyrazolyl)methanesulfonate {Li[SO3C(pz)3], 2}, potassium hydrotris(3,5-dimethyl-1-pyrazolyl)borate {K[HB(3,5-Me2pz)3], 3} and hydrotris(1-pyrazolyl)methane [HC(pz)3, 4], respectively. Treatment of [VO(OEt)3] with potassium hydrotris(1-pyrazolyl)borate {K[HB(pz)3]} led to the mixed ,3 -tris(pyrazolyl)borate and ,2 -bis(pyrazolyl)borate oxovanadium(IV) complex [VO{HB(pz)3}{H2B(pz)2}, 5]. The compounds were characterized by elemental analyses, IR, NMR and EPR spectroscopy, FAB and ESI mass spectrometry, cyclic voltammetry and, for 5, also by single crystal X-ray diffraction analysis. All complexes exhibit catalytic activity in the single-pot carboxylation [in trifluoroacetic acid/potassium peroxodisulfate (CF3COOH/K2S2O8)] of gaseous alkanes (methane and ethane) to carboxylic acids (yields up to 40%, TONs up to 157) and in the peroxidative oxidation [in water/acetonitrile (H2O/NCMe)] of liquid alkanes (cyclohexane and cyclopentane) to the corresponding alcohols and ketones (yields up to 24%, TONs up to 117), under mild conditions. [source] Synthesis of 1,3,4-oxa(or thia)diazaheterocycles starting from 2-(pyrrol-1'-y1)phthalimideJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 6 2001Anita Guesdon 1-(1,3-Dioxo-1,3-dihydro-2H -isoindol-2-yl)-1H -pyrrol-2 carbaldehyde 4 was synthesized by Vilsmeier-Haack reaction from 2-(pyrrol-1-yl) phthalimide. Reduction of 4 by sodium borohydride, or action of Grignard reagents on 4 led to the corresponding alcohols 5 which were cyclized to pyrroloxadiazino isoin-doles 1 by heating in the presence of silica gel. Transformation of the hydroxylactam 6 with acetic acid derivatives led to the esters 7 which gave, after saponification, pyrroloxa(or thia)diazepinoisoindolones 2 by intramolecular cyclization. [source] Crystallization and preliminary X-ray diffraction studies of the putative haloalkane dehalogenase DppA from Plesiocystis pacifica SIR-IACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2010Xenia Bogdanovi DppA from Plesiocystis pacifica SIR-I is a putative haloalkane dehalogenase (EC 3.8.1.5) and probably catalyzes the conversion of halogenated alkanes to the corresponding alcohols. The enzyme was expressed in Escherichia coli BL21 and purified to homogeneity by ammonium sulfate precipitation and reversed-phase and ion-exchange chromatography. The DppA protein was crystallized by the vapour-diffusion method and protein crystals suitable for data collection were obtained in the orthorhombic space group P21212. The DppA crystal diffracted X-rays to 1.9,Å resolution using an in-house X-ray generator. [source] Effect of Binary Combinations of Selected Toxic Compounds on Growth and Fermentation of Kluyveromyces marxianusBIOTECHNOLOGY PROGRESS, Issue 3 2004Jose M. Oliva The inhibitory effects of various lignocellulose degradation products on glucose fermentation by the thermotolerant yeast Kluyveromycesmarxianus were studied in batch cultures. The toxicity of the aromatic alcohol catechol and two aromatic aldehydes (4-hydroxybenzaldehyde and vanillin) was investigated in binary combinations. The aldehyde furfural that usually is present in relatively high concentration in hydrolyzates from pentose degradation was also tested. Experiments were conducted by combining agents at concentrations that individually caused 25% inhibition of growth. Compared to the relative toxicity of the individual compounds, combinations of furfural with catechol and 4-hydroxybenzaldehyde were additive (50% inhibition of growth). The other binary combinations assayed (catechol with 4-hydroxybenzaldehyde, and vanillin with catechol, furfural, or 4-hydroxybenzaldehyde) showed synergistic effect on toxicity and caused a 60,90% decrease in cell mass production. The presence of aldehydes in the fermentation medium strongly inhibited cell growth and ethanol production. Kluyveromyces marxianusreduces aldehydes to their corresponding alcohols to mitigate the toxicity of these compounds. The total reduction of aldehydes was needed to start ethanol production. Vanillin, in binary combination, was dramatically toxic and was the only compound for which inhibition could not be overcome by yeast strain assimilation, causing a 90% reduction in both cell growth and fermentation. [source] Synthesis and Liquid Crystalline Properties of Mono-, Di- and Tri- O -alkyl Pentaerythritol Derivatives Bearing Tri-, Di- or Monogalactosyl Heads: The Effects of Curvature of Molecular Packing on Mesophase FormationCHEMISTRY - A EUROPEAN JOURNAL, Issue 19 2007Fabienne Dumoulin Dr. Abstract Self-organisation and self-assembly are critical to the stability of synthetic and biological membranes. Of particular importance is consideration of the packing arrangements of the various molecular species. Both phospho- and glycolipids can pack in ways in which curvature can be introduced into self-organised or self-assembled systems. For instance, it is known that the degree of curvature can affect the structures of any condensed phases that are formed. In this article we report on a systematic study in which we have varied the shapes of glycolipids and examined the condensed phases that they form. In doing so, we have also unified the shape dependency of lyotropic liquid crystals with those of thermotropic liquid crystals. In order to undertake this systematic study a range of different pentaerythritol derivatives was synthesized, which covers combinations of one to three alkyl chains of different lengths (6,7,9,10,11,12,14,16 carbon atoms) and three to one galactosyl heads. Mono- and di- O -galactosyl derivatives were prepared directly by glycosylation of the corresponding alcohols using 2,3,4,6-tetra- O -benzoyl or acetyl - ,- D - galactopyranosyl trichloroacetimidate or bromide as the donors; the tri- O -galactosyl derivatives were synthesized from O -alkyl- O -benzyl di- O -galactosyl pentaerythritol intermediates, followed by de- O -benzylation and glycosylation steps. All of the fully deprotected products were obtained by standard methods, and their self-organising and self-assembling properties examined. [source] Facile and Efficient Reduction of Ketones in the Presence of Zinc Catalysts Modified by Phenol LigandsCHEMISTRY - AN ASIAN JOURNAL, Issue 9 2010Stephan Enthaler Dr. Abstract In the present study, the zinc-catalyzed hydrosilylation of various ketones to give their corresponding alcohols has been examined in detail. Diethyl zinc that can be modified by easily accessible phenol ligands allows the efficient reduction of various aryl and alkyl ketones. By using a practical in situ catalyst, excellent turnover frequencies up to 1000,h,1 and a broad functional group tolerance were achieved. Im Rahmen dieser Arbeit wird die Zink-katalysierte Hydrosilylierung von Ketonen zu den entsprechenden Silylethern mit anschließender Hydrolyse zu deren Alkoholen vorgestellt. Wobei exzellente Ausbeuten und Umsätze durch die Modifikation des katalytisch eingesetzten Diethylzink mit Phenolen erreicht werden konnten. Nach genauer Untersuchung verschiedenster Reaktionsparameter konnten turnover frequencies (TOF) von ca. 1000,h,1 erzielt werden. Die hervorragenden Eigenschaften des Katalysatorsystems konnte weiterhin in der Hydrosilylierung verschiedenster Ketone erfolgreich gezeigt werden. Zum besseren Verständnis der Reaktion wurden verschiedene mechanistische Experimente durchgeführt. [source] Chemo- and Stereoselective Iron-Catalyzed Hydrosilylation of KetonesCHEMISTRY - AN ASIAN JOURNAL, Issue 7 2010Daniele Addis Abstract The reduction of ketones with polymethylhydrosiloxane (PMHS) gives the corresponding alcohols in good to excellent yield applying iron-based catalyst systems. In the case of prochiral ketones, the use of Fe(OAc)2/(S,S)-Me-DuPhos leads to high enantioselectivity up to 99,%,ee. The reaction proceeds in the presence of several functional groups such as esters, halides as well as conjugated double bonds, with high chemoselectivity. The advantage of this protocol is that the reaction requires no activating agents or additives. [source] Syntheses, Characterizations, and Biological Activities of Tetradeca-4,8-dien-1-yl Acetates as Sex Attractants of Leaf-Mining Moth of the Genus Phyllonorycter (Lepidoptera: Gracillariidae)CHEMISTRY & BIODIVERSITY, Issue 9 2009Ilme Liblikas Abstract The four possible isomers of tetradeca-4,8-dien-1-yl acetate and corresponding alcohols were synthesized stereoselectively by synthetic routes employing Wittig coupling reaction for the preparation of (Z,E)- and (Z,Z)-isomers, and alkylation of terminal alkynes for the preparation of (E,E)- and (E,Z)-isomers as the key steps. Synthetic products were characterized by 13C- and 1H-NMR spectroscopy as well as mass-spectrometric methods. All four isomers gave distinctive mass spectra where m/z 81 fragments clearly dominated. Elution order, followed by retention index presented in parenthesis, of tetradeca-4,8-dien-1-ols was determined as (Z,Z) (2082.1), (Z,E) (2082.8), (E,E) (2083.1), and (E,Z) (2083.2) from unpolar SPB-1 column, and as (E,E) (2210.2), (Z,E) (2222.1), (E,Z) (2223.4), and (Z,Z) (2224.7) from polar DB-WAX column. The isomers of tetradeca-4,8-dien-1-yl acetates eluted in the order of (Z,Z) (2176.1), (Z,E) (2178.4), (E,Z) (2185.9), and (E,E) (2186.4) from SPB-1, and (Z,E) (2124.3), (E,E) (2157.7), (Z,Z) (2128.9), and (E,Z) (2135.9) from DB-WAX columns. Field-screening tests for attractiveness of tetradeca-4,8-dien-1-yl acetates revealed that (4Z,8E)-tetradeca-4,8-dien-1-yl acetate significantly attracted Phyllonorycter coryli and Chrysoesthia drurella males. (4E,8E)-Tetradeca-4,8-dien-1-yl acetate was the most efficient attractant for Ph. esperella and Ph. saportella males, and (4E,8Z)-tetradeca-4,8-dien-1-yl acetate was attractive to Ph. cerasicolella males. 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