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Diol
Kinds of Diol Terms modified by Diol Selected AbstractsMonitoring of mutarotation of monosaccharides by hydrophilic interaction chromatographyJOURNAL OF SEPARATION SCIENCE, JSS, Issue 6-7 2010í Pazourek Abstract Calibration based on the "single-point calibration method", a simple exponential transformation of the response function of an evaporative light scattering detector was improved and applied to analysis of selected saccharides under hydrophilic interaction chromatography mode (a polar phase LiChrospher100 DIOL, mobile phase acetonitrile/water). The improved approach to the calibration procedure yielded a calibration curve with an excellent linearity (quality coefficient <5%). This quantitative evaluation of chromatograms of D -galactose suggested that not only anomers but even pyranose and furanose forms of the anomers could be resolved , the resulting calculations of abundance of the anomeric form strongly correlated with data from the literature obtained mostly by NMR studies (analogous results were also obtained for D -arabinose, D -glucose, and D -mannose). Because of the rapid separation (retention time less than 10,min), the observed correlation enabled to monitor anomeric conversion (mutarotation) of monosaccharides. [source] Towards Selective Recognition of Sialic Acid Through Simultaneous Binding to Its cis -Diol and Carboxylate FunctionsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 17 2010Martín Regueiro-Figueroa Abstract A series of receptors containing phenylboronic acid and urea or thiourea units have been designed for simultaneous recognition of the cis -diol and carboxylate functions of sialic acids, which are known to be overexpressed on the surfaces of tumor cells. The interaction of the receptors with 5-acetylneuraminic acid (Neu5Ac) and 2-,- O -methyl Neu5Ac (MeNeu5Ac) in DMSO solution has been investigated bymeans of spectrophotometric titrations and 1H, 13C, and 11B NMR spectroscopy. Additionally, we have also investigated the binding of these receptors with competing monosaccharides such as D -(+)-glucose, D -fructose, methyl ,- D -galactoside, and methyl ,- D -mannoside. Our results show that 2-{[3-(4-nitrophenyl)thioureido]methyl}phenylboronic acid (3a) recognizes both Neu5Ac and MeNeu5Ac with good selectivity with regard to the remaining monosaccharides investigated. DFT calculations performed at the B3LYP/6-31G(d) level show that this selectivity is due to a cooperative two-site binding of Neu5Ac through 1) ester formation by interaction at the phenylboronic acid function of the receptor and 2) hydrogen-bond interaction between the thiourea moiety and the carboxylate group of Neu5Ac. Compound 3a can therefore be considered a promising synthon for the design of contrast agents for magnetic resonance imaging of tumors. In contrast, the analogue of 3a containing a urea moiety , compound 3b , displays strong binding to all monosaccharides investigated, due to two-site binding through interaction on the phenylboronic acid function of the receptor and a hydrogen-bond interaction between the urea moiety and the sugar hydroxy groups. [source] A Bicyclic Monoterpene Diol and UVB Stimulate BRCA1 Phosphorylation in Human Keratinocytes,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2003Matthew T. Canning ABSTRACT BRCA1 (breast cancer,associated gene 1) is a tumor suppressor gene that plays a role in DNA repair when phosphorylated. Many DNA-damaging agents including UVC and hydrogen peroxide have been shown to induce phosphorylation of BRCA1. Results of this study now show that both UVB and a bicyclic monoterpene diol (BMT diol) result in phosphorylation of BRCA1. This phosphorylation was maximal 2 h after treatment with either agent and declined to basal levels by 24 h. Inhibitor studies revealed that both UVB and the BMT diol phosphorylate BRCA1 through the FK506-binding protein,FKBP rapamycin-associated binding protein pathway, but the BMT diol also led to phosphorylation of BRCA1 through casein kinase II. This suggests that the signaling pathways for UVB and the BMT diol may diverge. Results of this study also show that the BMT diol stimulates the repair of UVB-induced cyclobutane pyrimidine dimers (CPD). Inhibitors of BMT diol,induced BRCA1 phosphorylation blocked the BMT diol,stimulated repair of CPD. This indicates that the BMT diol induces the phosphorylation of BRCA1, which, in turn, leads to an increase in repair of UVB-induced CPD. Therefore, this BMT diol may be useful for ameliorating the damaging effects of UVB. [source] ChemInform Abstract: Insight into Acid-Mediated Asymmetric Spirocyclization in the Presence of a Chiral Diol.CHEMINFORM, Issue 11 2001Toshihiro Kiguchi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: The Conversion of Racemic Terminal Epoxides into Either (+)- or (-)-Diol ,- and ,-Lactones.CHEMINFORM, Issue 9 2001Zhi-Yu Liu Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] 4- exo - dig Cyclocarbopalladation: A Straightforward Synthesis of Cyclobutanediols from Acyclic ,-Bromopropargylic Diols under Microwave Irradiation Conditions,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 6 2006Christophe Bour Abstract Treatment of acyclic ,-bromopropargylic diols with tributylstannylated alkynes under palladium catalysis and microwave irradiation conditions gives high yields of the bis(alkylidene)cyclobutanediol derivatives and cyclobutenediols through an efficient 4- exo - dig cyclocarbopalladation. The cyclization is general with a wide variety of alkyne derivatives and gives access to new cyclobutane ring systems bearing one exocyclic double bond and one eneyne substituent as well as bicyclic dienes sharing a common double bond that may be of interest for further elaborations of complex molecules. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Oxidation of Alcohols and vic -Diols with H2O2 by Using Catalytic Amounts of N -Methylpyrrolidin-2-one HydrotribromideEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 3 2006Jomy K. Joseph Abstract A variety of secondary alcohols, 1,2-diols and primary alcohols were selectively oxidized in excellent yields to their corresponding ketones, 1,2-diketones and aldehydes with aqueous 30,% hydrogen peroxide in refluxing acetonitrile in the presence of catalytic amounts of N -methylpyrrolidin-2-one hydrotribromide (MPHT). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Aminium Hexachloroantimonate Salts as Latent Sources of Antimony Pentachloride in Pinacolic Rearrangement of Vicinal DiolsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 8 2005Francesco Ciminale, Luigi Lopez Abstract Rearrangements of various vicinal diols (1a,f) induced by hexachloroantimonate aminium salts A or B were found to occur in a similar manner when antimony pentachloride was used instead of aminium salts. Antimony pentachloride is proposed as the active catalytic species, possibly deriving from the oxidation of the hexachloroantimonate anion SbCl6, by the aminium counterpart. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Organocatalysis in Natural Product Synthesis: A Simple One-Pot Approach to Optically Active ,-DiolsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2009Nikolaj Røjkjær Andersen Abstract Optically active ,-diols have been prepared using an organocatalytic one-pot approach from ,,,-unsaturated aldehydes using (E) -benzaldehyde oxime as nucleophile in an oxa-Michael reaction with subsequent in situ reduction or Grignard addition. With this protocol at hand, two biologically active compounds, an insect sex pheromone and a glycerol kinase substrate have been synthesized. [source] Promiscuous Substrate Binding Explains the Enzymatic Stereo- and Regiocontrolled Synthesis of Enantiopure Hydroxy Ketones and DiolsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Marcela Kurina-Sanz Abstract Regio- and stereoselective reductions of several diketones to afford enantiopure hydroxy ketones or diols were accomplished using isolated alcohol dehydrogenases (ADHs). Results could be rationalised taking into account different (promiscuous) substrate-binding modes in the active site of the enzyme. Furthermore, interesting natural cyclic diketones were also reduced with high regio- and stereoselectivity. Some of the 1,2- and 1,3-diketones used in this study were reduced by employing a low excess of the hydrogen donor (2-propanol) due to the quasi-irreversibility of these ADH-catalysed processes. Thus, using lower quantities of co-substrate, scale-up could be easily achieved. [source] Biocatalytic Asymmetric Dihydroxylation of Conjugated Mono- and Poly-alkenes to Yield Enantiopure Cyclic cis -DiolsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7-8 2005Derek Abstract Dioxygenase-catalysed asymmetric dihydroxylation, of a series of conjugated monoalkenes and polyenes, was found to yield the corresponding monols and 1,2-dihydrodiols. The diol metabolites were obtained from monosubstituted, gem -disubstituted, cis -disubstituted, and trisubstituted alkene substrates, using whole cells of Pseudomonas putida strains containing toluene and naphthalene dioxygenases. Dioxygenase selection and alkene type were established as important factors, in the preference for dioxygenase-catalysed 1,2-dihydroxylation of conjugated alkene or arene groups, and monohydroxylation at benzylic or allylic centres. Competition from allylic hydroxylation of methyl groups was observed only when naphthalene dioxygenase was used as biocatalyst. The structures, enantiomeric excess values and absolute configurations of the bioproducts, were determined by a combination of stereochemical correlation, spectroscopy (NMR and CD) and X-ray diffraction methods. cis -1,2-Diol metabolites from arenes, cyclic alkenes and dienes were generally observed to be enantiopure (>98% ee), while 1,2-diols from acyclic alkenes had lower enantiomeric excess values (<88% ee). The enantiopure cis -diol metabolite of a gem -disubstituted fulvene was used as precursor in a new chemoenzymatic route to a novel C2 -symmetrical ketone. [source] Analysis of alcohols, as dimethylglycine esters, by electrospray ionization tandem mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 3 2001Dr David W. Johnson Abstract Dimethylglycine (DMG) esters are new derivatives for the rapid, sensitive and selective analysis of primary and secondary alcohols, in complex mixtures, by electrospray ionization tandem mass spectrometry (ESI-MS/MS). Their development was inspired by the use of the complementary dimethylaminoethyl esters for the trace, rapid analysis of fatty acids. DMG esters are simply prepared by heating a dichloromethane solution of the imidazolide of dimethylglycine, containing triethylamine, and an alcohol. DMG esters of long-chain fatty alcohols, isoprenoidal alcohols and hydroxy-acids are analysed by electrospray ionization tandem mass spectrometry with a precursor ion of m/z 104 scan. Diols, glyceryl esters, glyceryl ethers and some sterols are analysed by a neutral loss of 103 Da scan. Trimethylglycine (TMG) ester iodides, prepared by alkylation of DMG esters with methyl iodide, are more sensitive derivatives for molecules containing secondary alcohol groups, such as cholesterol and gibberellic acid. They are analysed by a precursor ion of m/z 118 scan. DMG or TMG derivatives were shown to be at least comparable and sometimes an order of magnitude more sensitive than N -methylpyridyl ether derivatives for ESI-MS/MS analysis of the different classes of alcohols. Applications of these derivatives for the diagnosis of inherited disorders and the analysis of natural products are presented. Copyright © 2001 John Wiley & Sons, Ltd. [source] Study of Polyurethane Formulations Containing Diols Obtained via Glycolysis of Poly(ethylene terephthalate) (PET) by Oligoesters Diols through a Reactive Extrusion ProcessMACROMOLECULAR MATERIALS & ENGINEERING, Issue 7 2005Gaël Colomines Abstract Summary: The glycolysis of PET by oligoester diols in the presence of zinc acetate was carried out in two successive twin-screw extruders with total residence times of 4 min and without solvent. These new glycolysates were analyzed and used in polyurethane formulation with a commercial polyol. The reactivity of these formulations was studied. The mechanical properties, thermal and swelling behavior of these polyurethanes were investigated. Mechanical properties are improved with the addition of glycolysate. The thermal behavior is not modified with the addition of glycolysate. The swelling behavior of the material depends on the solvent nature. The addition of glycolysate allows a decrease in material swelling in chloroform but increases this swelling in acetone. [source] Synthesis of Cyclic Imides from Simple Diols,ANGEWANDTE CHEMIE, Issue 36 2010Jian Zhang Ein in situ erzeugter Rutheniumkatalysator überführt einfache Diole mit primären Aminen in einer Stufe in cyclische Imide. Atomökonomische und leicht ausführbare Synthesen von Succinimiden, Phthalimiden und Glutarimiden, wichtige Bausteine für Naturalstoffe und Wirkstoffe, werden vorgestellt. [source] Enantio- and Diastereoselective Chemoenzymatic Synthesis of C2-Symmetric Biaryl-Containing DiolsCHEMCATCHEM, Issue 1 2010Edyta Burda Abstract An enantio- and diastereoselective synthesis of C2-symmetric diols bearing a biphenyl-framework has been developed by means of an enzymatic reduction of the corresponding diketones, which were prepared by a Suzuki coupling reaction. Furthermore, a chemoenzymatic one-pot synthesis of a C2-symmetric diol in aqueous media has been realized through combination of the Suzuki coupling reaction and enzymatic reduction. Chiral stereoisomers of the biaryl-containing diols are prepared with diastereomeric ratios in excess of 25:1 and enantiomeric excesses of greater than 99,%. [source] ChemInform Abstract: Cyclodehydration of Fluorinated Diols Using the Mitsunobu Reaction: Highly Efficient Synthesis of Trifluoromethylated Cyclic Ethers.CHEMINFORM, Issue 40 2010G. K. Surya Prakash Abstract The title reaction of the diastereomerically pure diol (VII) affords the corresponding oxirane (VIII) with complete inversion of configuration. [source] ChemInform Abstract: Enantio- and Diastereoselective Chemoenzymatic Synthesis of C2-Symmetric Biaryl-Containing Diols.CHEMINFORM, Issue 21 2010Edyta Burda Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: An Efficient Oxidation of Element-Containing Propargyl Alcohols and Acetylenic ,-Diols by 2-Iodoxybenzoic Acid (IBX).CHEMINFORM, Issue 13 2009Irina A. Novokshonova Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Synthesis of Diketones and ,-Hydroxy Ketones from Methyl Ketones and ,,,-Diols by an [IrCl(cod)]2/PPh3/KOH System.CHEMINFORM, Issue 39 2008Kensaku Maeda Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: New Route to N-Alkylated trans-Pyrrolidine Diols from 2,2,3,3-Tetramethoxybutane-Protected Dimethyl Tartrate.CHEMINFORM, Issue 39 2008J. Graca Martins Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: In situ Generation of Ylides for Tandem Oxidation,Olefination Reactions of Unactivated Diols.CHEMINFORM, Issue 30 2008David J. Phillips Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: An Efficient Synthesis of Nitrogen Heterocycles by Cp*Ir-Catalyzed N-Cycloalkylation of Primary Amines with Diols.CHEMINFORM, Issue 27 2008Ken-ichi Fujita Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Asymmetric Conjugate Alkenylation of Enones Catalyzed by Chiral Diols.CHEMINFORM, Issue 35 2007T. Robert Wu Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Chiral Diols: A New Class of Additives for Direct Aldol Reaction Catalyzed by L-Proline.CHEMINFORM, Issue 16 2007Yan Zhou Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Desymmetrization of Diols by a Tandem Oxidation/Wittig Olefination Reaction.CHEMINFORM, Issue 41 2006David J. Phillips Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Synthesis of Diols Using the Hypervalent Iodine(III) Reagent, Phenyliodine(III) Bis(trifluoroacetate).CHEMINFORM, Issue 36 2006Murat Celik Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Non-Acid Catalytic Acetalization of Aldehydes with Diols in Ionic Liquids.CHEMINFORM, Issue 27 2005Fan Zhang Abstract For Abstract see ChemInform Abstract in Full Text. [source] Cp*Ir Complex-Catalyzed N-Heterocyclization of Primary Amines with Diols: A New Catalytic System for Environmentally Benign Synthesis of Cyclic Amines.CHEMINFORM, Issue 4 2005Ken-ichi Fujita Abstract For Abstract see ChemInform Abstract in Full Text. [source] Synthesis of N-Heterocyclic Diols by Diastereoselective Pinacol Coupling Reactions.CHEMINFORM, Issue 15 2004Sandeep Handa Abstract For Abstract see ChemInform Abstract in Full Text. [source] Silenes as Novel Synthetic Reagents: Synthesis of Diols and Lactones from Simple Alkyldienes.CHEMINFORM, Issue 13 2004Malcolm B. Berry Abstract For Abstract see ChemInform Abstract in Full Text. [source] | ||||||||||||||||||||||||||||||||||||||||