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Furans
Kinds of Furans Terms modified by Furans Selected AbstractsCatalytic, Asymmetric Vinylogous Mukaiyama Aldol Reactions of Pyrrole- and Furan-Based Dienoxy Silanes: How the Diene Heteroatom Impacts StereocontrolADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2010Claudio Curti Abstract Denmark's chiral bisphosphoramide/silicon tetrachloride system performs as an excellent Lewis base-Lewis acid catalyst for the vinylogous Mukaiyama aldol reaction of pyrrole- and furan-based dienoxy silanes with aromatic and heteroaromatic aldehydes. This asymmetric methodology provides a powerful synthetic entry to a variety of ,-hydroxylated ,-butenolide-type frameworks with high efficiency and valuable margins of regio-, diastereo-, and enantioselectivity. Notably, the nature of the heteroatom within the vinylogous dienoxy silane donor heavily impacts the diastereocontrol, with syn -configured aldol adducts emerging from pyrroles bearing electron-withdrawing N -protecting groups (Boc, Ts, and Cbz) and anti -configured adducts prevailing when furan- or N -alkyl/alkenylpyrrole donors are involved. [source] Lewis Acid-Mediated Selective Cycloadditions of Vinylidenecyclopropanes with Aromatic Aldehydes: An Efficient Protocol for the Synthesis of Benzo[c]fluorene, Furan and Furo[2,3- b]furan DerivativesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1-2 2009Chenliang Su Abstract Three kinds of Lewis acid-mediated reactions of vinylidenecyclopropanes and aromatic aldehydes are disclosed in this paper, providing an efficient and selective synthesis of a variety of functionalized benzo[c]fluorene, furan and furo[2,3- b]furan derivatives. [source] ChemInform Abstract: Organocatalytic Asymmetric Diels,Alder Reaction of Furan under High Pressure.CHEMINFORM, Issue 34 2010Akiko Mimoto Abstract The combined use of high pressure and organocatalysis promotes the title reaction. [source] ChemInform Abstract: Ruthenium/TFA-Catalyzed Coupling of Activated Secondary Propargylic Alcohols with Cyclic 1,3-Diones: Furan versus Pyran Ring Formation.CHEMINFORM, Issue 50 2008Victorio Cadierno 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] Furan Decorated Nucleoside Analogues as Fluorescent Probes: Synthesis, Photophysical Evaluation, and Site-Specific Incorporation.CHEMINFORM, Issue 26 2007Nicholas J. Greco 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] Organocatalytic Asymmetric Aza-Friedel,Crafts Alkylation of Furan.CHEMINFORM, Issue 5 2005Daisuke Uraguchi Abstract For Abstract see ChemInform Abstract in Full Text. [source] Bi(OTf)3/[bmim]BF4 as Novel and Reusable Catalytic System for the Synthesis of Furan, Pyrrole and Thiophene Derivatives.CHEMINFORM, Issue 44 2004J. S. Yadav Abstract For Abstract see ChemInform Abstract in Full Text. [source] Catalytic Oxidation of Furan and Hydrofuran Compounds.CHEMINFORM, Issue 20 2003Part 7. No abstract is available for this article. [source] ChemInform Abstract: Computational Studies on the BF3 -Catalyzed Cycloaddition of Furan with Methyl Vinyl Ketone: A New Look at Lewis Acid Catalysis.CHEMINFORM, Issue 4 2001Martin Avalos 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] Protonation of Pyrrole and Furan by H3O+ and NH4+ in the Gas Phase: A Density Functional Theory StudyCHINESE JOURNAL OF CHEMISTRY, Issue 3 2006Kuo Zeng Abstract Density functional theory and ab initio calculations have been used to determine structures and stabilities of the protonated aromatics species AH+ and AH22+ (A=pyrrole, furan). Possible mechanisms and relative energetics for protonation of pyrrole and furan by H3O+ and AH4+ in the gas phase have been explored. Calculations show that the C, -protonated species was the most stable structure for AH+, and the protonated AH+ might accommodate the second proton to yield AH22+ if the free proton was available. The gas-phase H3O+ could protonate pyrrole and furan with significant exothermicity and almost without barrier. The proton transfer from AH4+ to pyrrole and furan has a barrier ranging from 33.5 to 39.3 kJ/mol in the gas phase. [source] Gold(I)-Catalyzed Tandem Rearrangement,Nucleophilic Substitution of ,-Acetoxy Alkynyl Oxiranes or Aziridines: Efficient Approach to Furans and PyrrolesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 9 2010Aurélien Blanc Abstract Highly substituted furans and pyrroles were efficiently formed by a new gold(I)-catalyzed tandem rearrangement,nucleophilic substitution of acetoxylated alkynyl oxiranes and aziridines in the presence of various nucleophiles. [source] Microwave-Assisted Paal,Knorr Reaction , Three-Step Regiocontrolled Synthesis of Polysubstituted Furans, Pyrroles and ThiophenesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 24 2005Giacomo Minetto Abstract An efficient and highly versatile synthesis of furans, pyrroles and thiophenes is described. Starting from commercially available or easily prepared ,-keto esters, functional homologation provides differently substituted 1,4-diketones that can be transformed, through a microwave-assisted Paal,Knorr condensation, into the corresponding methoxycarbonyl heterocycles. The methoxycarbonyl moiety can be directly transformed into an NH2 group by hydrolysis to carboxylic acid and Curtius rearrangement or into an amide by reaction with a primary amine in the presence of Me3Al. The method is compatible with the presence of a CbzNH group so that the final heterocycle can be inserted into a peptide sequence as a turn inducer. By using this procedure, a collection of more than 60 different tetrasubstitued pyrroles or trisubstituted thiophenes has been prepared. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Environmental issues related to end-of-life options of plastics containing brominated flame retardantsFIRE AND MATERIALS, Issue 5 2004Lein Tange Abstract Bromine is used as the building block for some of the most effective flame retarding agents available to the plastics industry today. They are used to protect against the risk of accidental fires in a wide range of Electrical and Electronic Equipment (EEE). Brominated flame retardants (BFRs), as all flame retardants, act to decrease the risk of fire by increasing the fire resistance of the materials in which they are applied. There is a perception that BFRs affect adversely the end-of-life management of plastics through formation of Polybrominated Dibenzo Dioxins and Dibenzo Furans (PBDD/F). In fact, there exists a wide range of data and practical experience demonstrating that the end-of-life management of plastics containing BFRs is fully compliant with legislation setting the strictest limit values for PBDD/F and is fully compatible with an integrated waste management concept. Copyright © 2004 John Wiley & Sons, Ltd. [source] New Synthesis of Furans: the Rhodium-Catalysed Carbonylative Addition of Arylboronic Acids to Propargylic Alcohols/ Cyclisation SequenceADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010Julien Dheur Abstract The rhodium-catalysed carbonylative addition of arylboronic acids to propargylic alcohols yields gamma-hydroxy enones that are readily cyclised through a dehydration step to the corresponding furan analogues. The transformation was improved thanks to the screening of the reaction conditions and consequent improvements were obtained from the use of dicarbonylrhodium iodide [Rh(CO)2I]2 as catalyst precursor. The generalisation of the reaction was then further investigated by employing variously substituted arylboronic acids and propargylic alcohols. [source] Silver-Catalyzed One-Pot Cyclization Reaction of Electron- Deficient Alkynes and 2-Yn-1-ols: An Efficient Domino Process to Polysubstituted FuransADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 1 2010Hua Cao Abstract Transition metal-catalyzed domino reactions have been used as powerful tools for the preparation of polysubstituted furans in a one-pot manner. In this paper, an efficient synthetic method was developed for the construction of tri- or tetrasubstituted furans from electron-deficient alkynes and 2-yn-1-ols by a silver-catalyzed domino reaction. It is especially noteworthy that a 2,3,5-trisubstituted 4-ynyl-furan was formally obtained in an extremely direct manner without tedious stepwise synthesis. In addition, regio-isomeric furans were observed when substituted aryl alkynyl ketones were employed. This methodology represents a highly efficient synthetic route to electron-deficient furans for which catalytic approaches are scarce. The reaction proceeds efficiently under mild conditions with commercially available catalysts and materials. [source] Gold Catalysis: Efficient 1,3-Induction with Diastereotopic Homopropargyl Alcohols in the Phenol SynthesisADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2009A. Stephen Abstract Furans with diastereotopic alkynyl groups were prepared and then converted to anellated phenols in gold-catalyzed reactions. In all cases a highly diastereoselective reaction was observed. The stereochemical outcome of the 1,3-induction could be assigned by two independent crystal structure analyses, showing a cis -arrangement of the two alkyl substituents on the benzoanellated cyclohexene ring. [source] Palladium(II)-Catalyzed Domino Reaction of 2-(1-Alkynyl)-2-alken-1-ones with Nucleophiles: Scope, Mechanism and Synthetic Application in the Synthesis of 3,4-Fused Bicyclic Tetrasubstituted FuransADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4 2009Yuanjing Xiao Abstract Described herein is the development of a palladium(II)-catalyzed two- or three-component reaction of 2-(1-alkynyl)-2-alken-1-ones with nucleophiles and allylic chlorides. Various types of nucleophiles such as O- , N- , C -based nucleophiles and olefin-tethered O- , N- , C -based nucleophiles were investigated. The scope, mechanism and application of this Pd(II)-catalyzed domino reaction were studied. In these transformations, the palladium catalyst exhibits a dual role, serving simultaneously as a Lewis acid and a transition metal. Two possible reaction pathways (cross-coupling reaction vs. Heck reaction) from the same intermediate furanylpalladium species were observed. The reaction pathway is dependent on the property of the nucleophile and the length of the tethered chain as well. When olefin-tethered O -based nucleophiles were used, only the cross-coupling reaction pathway was observed, in contrast, both reaction pathways were observed when olefin-tethered C -based nucleophiles were employed. The product ratio is dependent on the length of the tethered chain. Furthermore, ring-closing metathesis (RCM) of corresponding furans with CC bonds provides an easy method for the preparation of functionalized oxygen-heterocycles , 3,4-fused bicyclic furans. It is also noteworthy that allylic chloride can be as an oxidant besides its well known function as an alkylating reagent. [source] Palladium-Catalyzed Direct C-4 Arylation of 2,5-Disubstituted Furans with Aryl BromidesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2008Aditya Abstract A simple and atom-economic procedure for the selective C-4 arylation of 2,5-disubstituted furans via CH bond activation using electron-deficient aryl bromides is reported. Only 0.5 mol% of the commercially available dimeric (allene)palladium chloride, [Pd(C3H5)Cl]2, was employed as catalyst. This environmentally attractive procedure has been found to be tolerant to a variety of functional groups on the aryl bromide such as carbonyl, nitrile, nitro, fluoro, ester or trifluoromethyl. [source] Synthesis of 3-Substituted Furans by HydroformylationADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 4-5 2006Perli Nanayakkara Abstract A simple and novel method for the synthesis of 3-substituted furans by the hydroformylation of substituted propargylic alcohols is described using rhodium acetate and triphenylphosphine in dichloromethane. The hydroformylation reaction proceeds in a regioselective manner under mild reaction conditions. This novel methodology is versatile and can be applied to the synthesis of a variety of 3-aryl-substituted furans. [source] Studies with enaminones: synthesis of new coumarin-3-yl azoles, coumarin-3-yl azines, coumarin-3-yl azoloazines, coumarin-3-yl pyrone and coumarin-2-yl benzo[b]FuransJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 4 2001Fathy Mohamed Abel Aziz El-Taweel 3-Acetylcoumarine was condensed with dimethylformamide dimethylacetal (DMFDMA) to yield the enaminone, which reacts readily with hydroxylamine and with hydrazines to yield coumarin-3-ylisoxazoles and coumarin-3-ylpyrazoles respectively. Reaction of the enaminone with benzamidine hydrochloride and 3-amino-1,2,4-1H -triazole affords the pyrimidine and triazolo[3,4- b]pyrimidine. The enaminone reacts with hippuric acid and with the dithiocarboxylic acid to yield pyranones. The reaction of the enaminone with 3-amino-1H -1,2,4-triazole gives the triazolo[3,4- b]pyrimidine. The enaminone underwent self dimerization on reflux in acetic acid ammonium acetate to yield the coumarinyl pyridines and reacted with ketone under the same conditions to yield the pyridine. The reaction of the enaminone with 1,4-benzoquinone and 1,4-naphthoquinone gives benzofuryl coumarine derivatives. [source] ChemInform Abstract: Copper(I)-Catalyzed Synthesis of Polysubstituted Furans from Alkynoates and 1,3-Dicarbonyl Compounds in the Presence of Oxygen.CHEMINFORM, Issue 36 2010Rulong Yan No abstract is available for this article. [source] ChemInform Abstract: Enantioselective Friedel,Crafts Alkylation of Indoles, Pyrroles, and Furans with Trifluoropyruvate Catalyzed by Chiral Phosphoric Acid.CHEMINFORM, Issue 26 2010Wataru Kashikura 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: A New Synthesis of 8-Oxabicyclo[3.2.1]octan-2-one and Its Use for the Preparation of Cycloheptane Annulated Furans.CHEMINFORM, Issue 16 2010Henning Hopf 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: Cationic Gold(I)-Mediated Intramolecular Cyclization of 3-Alkyne-1,2-diols and 1-Amino-3-alkyn-2-ols: A Practical Route to Furans and Pyrroles.CHEMINFORM, Issue 12 2010Masahiro Egi 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 Extremely Facile Synthesis of Furans, Pyrroles, and Thiophenes by the Dehydrative Cyclization of Propargyl Alcohols.CHEMINFORM, Issue 11 2010Aaron Aponick 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: Palladium-Catalyzed Dehydrogenative Coupling of Furans with Styrenes.CHEMINFORM, Issue 4 2010Chahinez Aouf 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: Platinum- and Palladium-Catalyzed Sequential Reactions: Regioselective Synthesis of 9-Fluorenylidenes from 9-Ethynylfluoren-9-yl Carboxylates and Furans.CHEMINFORM, Issue 50 2009Koji Miki 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: Efficient One-Pot 1,3-Dibromo-5,5-dimethylhydantoin (DBH)-Catalyzed Synthesis of Highly Substituted Furans.CHEMINFORM, Issue 29 2009Hassan Ghasemnejad-Bosra 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: FeCl3 -Catalyzed Propargylation,Isomerization Tandem Reaction: A Facile One-Pot Synthesis of Substituted Furans.CHEMINFORM, Issue 15 2009Wen-hua Ji 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 Synthetic Approach for the Construction of Multisubstituted 2-Acyl Furans by the IBX-Mediated Cascade Oxidation/Cyclization of cis-2-En-4-yn-1-ols (IBX = 2-Iodoxybenzoic Acid).CHEMINFORM, Issue 9 2009Xiangwei Du 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] | |||||||||||||||||||||||||||||||||||||