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Dicarbonyl Compounds (dicarbonyl + compound)
Selected AbstractsChemInform Abstract: GaCl3 -Promoted Ethenylation of Silylated ,-Dicarbonyl Compound with Silylethyne.CHEMINFORM, Issue 28 2001Synthesis of Ethenylmalonate. 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] Phosphotungstic Acid Catalyzed Direct Benzylation of ,-Dicarbonyl CompoundsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 29 2008Guan-Wu Wang Abstract 12-Phosphotungstic acid was used as an efficient, ecofriendly, and air- and moisture-stable catalyst to promote the direct substitution of the hydroxy group of benzylic and allylic alcohols with various ,-dicarbonyl compounds. This powerful protocol for carbon,carbon bond-forming reactions provides monoalkylated dicarbonyl compounds in high yields with great efficiency.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Various ,-Oxygen Functionalizations of ,-Dicarbonyl Compounds Mediated by the Hypervalent Iodine(III) Reagent p -Iodotoluene Difluoride with Different Oxygen-Containing NucleophilesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010Jun Yu Abstract p -Iodotoluene difluoride (p -Tol-IF2) has been found to be a general reagent for the effective introduction of various oxygen-containing functionalities including tosyloxy, mesyloxy, acetoxy, phosphoryloxy, methoxy, ethoxy and isopropoxy at the ,-position of ,-dicarbonyl compounds. These transformations can be readily realized by the use of the combined reagent of p -iodotoluene difluoride and various oxygen-containing nucleophilic compounds such as p -toluenesulfonic acid, methanesulfonic acid, acetic acid, diphenyl phosphate, methanol, ethanol and propan-2-ol under mild conditions, respectively. And, the in situ generated hypervalent iodine(III) species via ligand exchange between p -iodotoluene difluoride and the respective oxygen-containing nucleophiles are believed to be the real oxidizing agents in such transformations. [source] ChemInform Abstract: Boronic Acid Catalyzed Ene Carbocyclization of Acetylenic Dicarbonyl Compounds.CHEMINFORM, Issue 32 2010Meiling Li Abstract 3-Nitrobenzeneboronic acid is an efficient catalyst for the ene carbocyclization of pentynyl ketoesters (I). [source] ChemInform Abstract: Alkylation of ,-Dicarbonyl Compounds as a Method for the Production of Functionally Substituted Dihydrofurans.CHEMINFORM, Issue 1 2010A. M. Maharramov 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: Transformations of C-Adducts of 1,4-Diazinium Salts with Dicarbonyl Compounds into Polycyclic Systems.CHEMINFORM, Issue 29 2009E. V. Verbitskiy 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: Trihaloisocyanuric Acids as Convenient Reagents for Regioselective Halogenation of ,-Dicarbonyl Compounds.CHEMINFORM, Issue 18 2009Gabriela F. Mendonca 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: Asymmetric Mannich Reaction of Dicarbonyl Compounds with ,-Amido Sulfones Catalyzed by Cinchona Alkaloids and Synthesis of Chiral Dihydropyrimidones.CHEMINFORM, Issue 18 2008Sha Lou 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] Three-Component Condensation of Hetarylguanidines with Aldehydes (Ketones) and Dicarbonyl Compounds.CHEMINFORM, Issue 26 2007A. Yu. 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] Reaction of Aromatic Aldehydes with ,-Dicarbonyl Compounds in a Catalytic System: Piperidinium Acetate , 1-Butyl-3-methylimidazolium Tetrafluoroborate Ionic Liquid.CHEMINFORM, Issue 30 2006E. S. Putilova 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] Direct Organocatalytic Asymmetric ,-Sulfenylation of Activated C,H Bonds in Lactones, Lactams, and ,-Dicarbonyl Compounds.CHEMINFORM, Issue 14 2006Sara Sobhani 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] Gold(I)-Catalyzed 5-endo-dig Carbocyclization of Acetylenic Dicarbonyl Compounds.CHEMINFORM, Issue 6 2005Steven T. Staben Abstract For Abstract see ChemInform Abstract in Full Text. [source] Preparation of Acyloins by Cerium-Catalyzed, Direct Hydroxylation of ,-Dicarbonyl Compounds with Molecular Oxygen.CHEMINFORM, Issue 22 2003Jens Christoffers Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Oxidative Free Radical Reactions Between 2-Benzyl-1,4-naphthoquinones and ,-Dicarbonyl Compounds.CHEMINFORM, Issue 1 2002An-I Tsai 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: Synthesis of Enantiopure N-Protected 4,5-Disubstituted 3-Pyrrolidinones and N-Protected 2,5-Disubstituted 3-Pyrrolidinones via the Dieckmann Reaction of Dicarbonyl Compounds Derived from Enantiopure ,-Amino Esters.CHEMINFORM, Issue 35 2001Yue Wang 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: Synthesis of Quinoxalines by Cyclization of ,-Arylimino Oximes of ,-Dicarbonyl Compounds.CHEMINFORM, Issue 15 2001N. P. Xekoukoulotakis 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] Palladium-Catalyzed Intramolecular Oxidative Alkylation of 4-Pentenyl ,-Dicarbonyl CompoundsCHEMISTRY - A EUROPEAN JOURNAL, Issue 24 2004Cong Liu Abstract Reaction of 8-nonene-2,4-dione with a catalytic amount of [PdCl2(CH3CN)2] (2; 5 mol,%) and a stoichiometric amount of CuCl2 (2.5 equiv) at room temperature for 3 h led to oxidative alkylation and formation of 2-acetyl-3-methyl-2-cyclohexenone in 80,% isolated yield. The oxidative alkylation of 4-pentenyl ,-diketones tolerated a number of terminal acyl groups and substitution at the C1 and C3 carbon atoms of the 4-pentenyl chain. Likewise, 4-pentenyl ,-keto esters that possessed geminal disubstitution at the C1, C2, or C3 carbon atom of the 4-pentenyl chain cyclized to form 2-carboalkoxy-2-cyclohexenones in moderate to good yield as the exclusive cyclized product. Deuterium-labeling experiments provided information regarding the mechanism of the palladium-catalyzed oxidative alkylation of 4-pentenyl ,-dicarbonyl compounds. [source] L -Proline Catalyzed Enamination of , -Dicarbonyl Compounds under Solvent-free ConditionsCHINESE JOURNAL OF CHEMISTRY, Issue 9 2008Dhiman KUNDU Abstract A simple, general and efficient method has been developed for synthesis of various , -enamino ketones and esters by reacting , -dicarbonyl compounds with amines using a catalytic amount of L -proline at room temperature under solvent-free conditions in excellent yields. [source] ChemInform Abstract: Selective Reduction of the Acyl Group in Cyclic ,-Acyl-,-dicarbonyl Compounds with Sodium Cyanoborohydride.CHEMINFORM, Issue 49 2001-Alkyl-, -dicarbonyl Compounds., Efficient Synthesis of Cyclic 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] Effect of methylglyoxal modification and phosphorylation on the chaperone and anti-apoptotic properties of heat shock protein 27JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 1 2006Tomoko Oya-Ito Abstract Heat shock protein 27 (Hsp27) is a stress-inducible protein in cells that functions as a molecular chaperone and also as an anti-apoptotic protein. Methylglyoxal (MGO) is a reactive dicarbonyl compound produced from cellular glycolytic intermediates that reacts non-enzymatically with proteins to form products such as argpyrimidine. We found considerable amount of Hsp27 in phosphorylated form (pHsp27) in human cataractous lenses. pHsp27 was the major argpyrimidine-modified protein in brunescent cataractous lenses. Modification by MGO enhanced the chaperone function of both pHsp27 and native Hsp27, but the effect on Hsp27 was at least three-times greater than on pHsp27. Phosphorylation of Hsp27 abolished its chaperone function. Transfer of Hsp27 using a cationic lipid inhibited staurosporine (SP)-induced apoptotic cell death by 53% in a human lens epithelial cell line (HLE B-3). MGO-modified Hsp27 had an even greater effect (62% inhibition). SP-induced reactive oxygen species in HLE-B3 cells was significantly lower in cells transferred with MGO-modified Hsp27 when compared to native Hsp27. In vitro incubation experiments showed that MGO-modified Hsp27 reduced the activity of caspase-9, and MGO-modified pHsp27 reduced activities of both caspase-9 and caspase-3. Based on these results, we propose that Hsp27 becomes a better anti-apoptotic protein after modification by MGO, which may be due to multiple mechanisms that include enhancement of chaperone function, reduction in oxidative stress, and inhibition of activity of caspases. Our results suggest that MGO modification and phosphorylation of Hsp27 may have important consequences for lens transparency and cataract development. J. Cell. Biochem. © 2006 Wiley-Liss, Inc. [source] Oxalic acid as a versatile catalyst for one pot facile synthesis of 3,4-dihydropyrimidin-2-(1H)-ones and their thione analoguesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 4 2008Jaiprakash N. Sangshetti 3,4-Dihydropyrimidin-2-(1H)-ones and their thione analogues are synthesized from the condensation of aromatic aldehydes, ,-dicarbonyl compound and urea or thiourea in presence of 5 mol% of oxalic acid in ethanol-water (1:2; v/v) under mild reaction conditions. The yields obtained are better and also the use of very inexpensive catalyst, environmentally benign solvent and easy work-up are the advantageous aspects of the present method. [source] Fructose-mediated non-enzymatic glycation: sweet coupling or bad modificationDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 5 2004Casper G. Schalkwijk Abstract The Maillard reaction is a process in which reducing sugars react spontaneously with amino groups in proteins to advanced glycation endproducts (AGEs). Although an elevated level of glucose had been thought to play a primary role in the Maillard reaction, on a molecular basis, glucose is among the least reactive sugars within biological systems. The formation of AGEs is now also known to result from the action of various metabolites other than glucose, which are primarily located intracellularly and participate in the non-enzymatic glycation reaction at a much faster rate, such as fructose, trioses and dicarbonyl compounds. In this review, we considered the glycation reaction with particular attention to the potential role of fructose and fructose metabolites. The two sources for fructose are an exogenous supply from the diet and the endogenous formation from glucose through the aldose reductase pathway. Despite its ,eightfold higher reactivity, the contribution of extracellular glycation by fructose is considerably less than that by glucose, because of the low plasma concentration of fructose (5 mmol/L glucose vs 35 µmol/L fructose). Intracellularly, fructose is elevated in a number of tissues of diabetic patients in which the polyol pathway is active. In the cells of these tissues, the concentrations of fructose and glucose are of the same magnitude. Although direct evidence is not yet available, it is likely that the high reactivity of fructose and its metabolites may substantially contribute to the formation of intracellular AGEs and may contribute to alterations of cellular proteins, dysfunction of cells and, subsequently, to vascular complications. Copyright © 2004 John Wiley & Sons, Ltd. [source] Phosphotungstic Acid Catalyzed Direct Benzylation of ,-Dicarbonyl CompoundsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 29 2008Guan-Wu Wang Abstract 12-Phosphotungstic acid was used as an efficient, ecofriendly, and air- and moisture-stable catalyst to promote the direct substitution of the hydroxy group of benzylic and allylic alcohols with various ,-dicarbonyl compounds. This powerful protocol for carbon,carbon bond-forming reactions provides monoalkylated dicarbonyl compounds in high yields with great efficiency.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Rational Color Tuning and Luminescent Properties of Functionalized Boron-Containing 2-Pyridyl Pyrrolide Complexes,ADVANCED FUNCTIONAL MATERIALS, Issue 4 2005H.-Y. Chen Abstract Three systematically functionalized pyrrolide ligands were prepared via the coupling of methyl vinyl ketone and the respective carbaldehyde reagents, followed by treatment of the pre-formed dicarbonyl compounds with (NH4)2CO3 in order to generate the required pyrrole fragment. These ligands readily reacted with the boron reagent BPh3 to afford the complexes [(pyro)BPh2] (2a), [(noro)BPh2] (2b), and [(xaro)BPh2] (2c), where (pyro)H, (noro)H, and (xaro)H represents the 2-pyridyl, 2-quinolinyl, and 2-quinoxalinyl pyrrole groups, respectively. Complexes 2a,2c give stable solutions in air, and show strong photoluminescence with emission peak maxima located at 490,nm, 510,nm, and 575,nm, respectively. Calculations based upon time-dependent density function theory (TDDFT) show that the S1 state in these complexes is attributed to an allowed (,-symmetry),,,,* (,-symmetry) transition located at the chelating pyrrolide moieties. Electroluminescence (EL) devices based on 2c were fabricated. The EL emission from 2c as the host-emitter, with the emission peak maximum shifted to 580,nm, was observed when BCP was used as the hole blocking material. This device produces saturated red-orange light-emission at an onset voltage of 8,V and a maximum brightness of 5000,cd,m,2 at a driving voltage of 15,V; the external quantum yield is estimated to be 0.5,%. [source] Various ,-Oxygen Functionalizations of ,-Dicarbonyl Compounds Mediated by the Hypervalent Iodine(III) Reagent p -Iodotoluene Difluoride with Different Oxygen-Containing NucleophilesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010Jun Yu Abstract p -Iodotoluene difluoride (p -Tol-IF2) has been found to be a general reagent for the effective introduction of various oxygen-containing functionalities including tosyloxy, mesyloxy, acetoxy, phosphoryloxy, methoxy, ethoxy and isopropoxy at the ,-position of ,-dicarbonyl compounds. These transformations can be readily realized by the use of the combined reagent of p -iodotoluene difluoride and various oxygen-containing nucleophilic compounds such as p -toluenesulfonic acid, methanesulfonic acid, acetic acid, diphenyl phosphate, methanol, ethanol and propan-2-ol under mild conditions, respectively. And, the in situ generated hypervalent iodine(III) species via ligand exchange between p -iodotoluene difluoride and the respective oxygen-containing nucleophiles are believed to be the real oxidizing agents in such transformations. [source] General Zinc-Catalyzed Conia-Ene Reactions of 1,3-Dicarbonyl Compounds with Alkynes Including the Classically Challenging Substrates under Neat ConditionsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2009Chen-Liang Deng Abstract A simple, versatile new approach to four-membered ring to six-membered ring products has been developed by zinc-catalyzed intramolecular Conia-ene reactions of 1,3-dicarbonyl compounds with alkynes. This new route allows a wide range of dicarbonyl compounds, including the classically challenging 1,3-diesters and N,N, -disubstituted 1,3-keto amides, to be used for the Conia-ene reaction with inexpensive zinc chloride (ZnCl2) under neat conditions. [source] Gold Catalysis: Dihydroisobenzofurans and Isochromanes by the Intramolecular Furan/Alkyne ReactionADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 16-17 2006A. Stephen Abstract A series of furyl alcohols and homofuryl alcohols was synthesized by reduction of furfurals or reaction of furyllithium compounds with epoxides and subsequent propargylation. The gold-catalyzed cycloisomerization of these products furnished dihydroisobenzofurans and isochromanes. Crystal structure analyses proved the sequence of the substituents for both classes of products. Unsaturated dicarbonyl compounds as side-products show the mechanistic relationship to the analogous platinum-catalyzed reactions. Neither ester groups, even on the 4-position of the furan ring, nor aryl bromides hinder the catalysis by gold. In the case of a substrate with an allyl ether in the side chain, a side-product, which provides evidence for a reaction of the alkyne with an inverse regioselectivity, was observed. [source] A General and Efficient Method for the Preparation of ,-Enamino Ketones and Esters Catalyzed by Indium TribromideADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2006Zhan-Hui Zhang Abstract A variety of ,-enamino ketones and esters have been synthesized in high to exellent yields by reacting ,-dicarbonyl compounds with amines in the presence of a catalytic amount of indium tribromide. The reaction proceeds smoothly at room temperature in a short reaction time under solvent-free conditions. [source] Ni(OAc)2: a highly efficient catalyst for the synthesis of enaminone and enamino ester derivatives under solvent-free conditionsAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 10 2010Ju-Yan Liu Abstract Ni(OAc)2 was found to be an efficient catalyst for the synthesis of ,-enamino ketones or esters from ,-dicarbonyl compounds and amines under solvent-free conditions. The reusability of the catalyst was successfully examined without noticeable loss of its catalytic activity. Copyright © 2010 John Wiley & Sons, Ltd. [source] Palladium-Catalyzed Intramolecular Oxidative Alkylation of 4-Pentenyl ,-Dicarbonyl CompoundsCHEMISTRY - A EUROPEAN JOURNAL, Issue 24 2004Cong Liu Abstract Reaction of 8-nonene-2,4-dione with a catalytic amount of [PdCl2(CH3CN)2] (2; 5 mol,%) and a stoichiometric amount of CuCl2 (2.5 equiv) at room temperature for 3 h led to oxidative alkylation and formation of 2-acetyl-3-methyl-2-cyclohexenone in 80,% isolated yield. The oxidative alkylation of 4-pentenyl ,-diketones tolerated a number of terminal acyl groups and substitution at the C1 and C3 carbon atoms of the 4-pentenyl chain. Likewise, 4-pentenyl ,-keto esters that possessed geminal disubstitution at the C1, C2, or C3 carbon atom of the 4-pentenyl chain cyclized to form 2-carboalkoxy-2-cyclohexenones in moderate to good yield as the exclusive cyclized product. Deuterium-labeling experiments provided information regarding the mechanism of the palladium-catalyzed oxidative alkylation of 4-pentenyl ,-dicarbonyl compounds. [source] | |||||||||||||||||||||||||