Home About us Contact
|
Home About us Contact | ||
|
|
||
Diels-Alder Reaction (diels-alder + reaction)
Selected AbstractsDiels-Alder Reactions of Ethyl , -Bromoacrylate with Open-chain Dienes,Synthesis of Ethyl 1,3-/ 1,4-CyclohexadienecarboxylatesCHINESE JOURNAL OF CHEMISTRY, Issue 4 2010Yingjie Li Abstract The Diels-Alder reactions of ethyl , -bromoacrylate 1 with open-chain dienes 2 were conducted under thermal or Lewis acid-catalysis conditions. In most cases, the cyclic adducts of 1-bromocyclohex-3-enecarboxylates 3 were formed in high yields with good regio- and stereoselectivity. Subsequent E2-elimination by treatment with DBU provided the corresponding 1,3- or 1,4-cyclohexadienecarboxylates depending on the relative configuration of the products. Starting from myrcene (7-methyl-3-methyleneocta-1,6-diene) the reaction sequence afforded the ester precursor of Georgywood with good yields. [source] Diels-Alder Reactions of N -Functionalized Acryloyl , -Pyrrolidone Derivatives Using FeCl3·6H2O as an Efficient Catalyst under Solvent-free ConditionsCHINESE JOURNAL OF CHEMISTRY, Issue 6 2007Wen Pei Abstract Diels-Alder reactions of N -functionalized acryloyl , -pyrrolidone derivatives were investigated, which were catalyzed by FeCl3·6H2O as an efficient catalyst under solvent-free conditions at room temperature. The corresponding cycloadducts with functionalized-pyrrolidone were prepared in high yield with high stereoselectivity by a green chemistry procedure. N -Functionalized acryloyl pyrrolidone derivatives, a kind of pyrrolidone-functionalized chelating ,,, -unsaturated ketone usable as a dienophile in Diels-Alder reaction, were synthesized by N -acylation procedure in ionic liquid as a novel synthetic method. [source] Regioselective synthesis of 2-methyl-2,5,6,11,12,13-hexahydro 4H indazolo[5,4-a]pyrrolo[3,4-c]carbazole-4-onesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 6 2009Ming Tao 2-Methyl-2,5,6,11,12,13-hexahydro 4H indazolo[5,4-a]pyrrolo[3,4-c]carbazole-4-one was synthesized utilizing a regioselective Diels-Alder reaction with 5-(1H-indol-2-yl)-2-methyl-6,7-dihydro-2H-indazole and ethyl cis -,-cyanoacrylate. Acetic acid and YtBr3 were the best solvent and catalyst for the regioselective Diels-Alder reaction. The chemistry was used to synthesize novel 8-pyrimidinyloxy-2,5,6,11,12,13-hexahydro 4H indazolo[5,4-a]pyrrolo[3,4-c]carbazole-4-ones that were screened and found to be potent inhibitors of DLK. J. Heterocyclic Chem., (2009). [source] A Diels-Alder/retro Diels-Alder strategy to synthesize polymers bearing maleimide side chainsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2007Tugba Dispinar Abstract Polymers containing thiol-reactive maleimide groups on their side chains have been synthesized by utilization of a novel methacrylate monomer containing a masked maleimide. Diels-Alder reaction between furan and maleimide was adapted for the protection of the reactive maleimide double bond prior to polymerization. AIBN initiated free radical polymerization was utilized for synthesis of copolymers containing masked maleimide groups. No unmasking of the maleimide group was evident under the polymerization conditions. The maleimide groups in the side chain of the polymers were unmasked into their reactive form by utilization of retro Diels-Alder reaction. This cycloreversion was monitored by thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), and 1H and 13C NMR spectroscopy. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4545,4551, 2007 [source] Protein Biochips: Oriented Surface Immobilization of Proteins,MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 2 2010Po-Chiao Lin Abstract Substantial progress in biochip technologies has established an efficient and reliable platform for advanced biological and biomedical applications. In particular, the use of protein biochips in high-throughput screens provides high content information. We briefly introduce here recent developments in protein biochip preparation with a special focus on our own work on new methods for protein immobilization and protein microarray fabrication, including the application of the Diels-Alder reaction, Staudinger ligation, ,click' sulfonamide formation, and the photochemical thiol-ene reaction. These chemical methods allow for oriented, site-specific protein conjugation on solid surfaces with high sensitivity and specificity under mild, aqueous conditions. [source] Diels,Alder "Click" Chemistry in Designing Dendritic MacromoleculesCHEMISTRY - A EUROPEAN JOURNAL, Issue 23 2009Grégory Franc Dr. Abstract Simple, versatile and green: Diels,Alder "click" chemistry is a simple, versatile and "greener" approach in the design of a diverse range of dendritic macromolecules (see scheme). In the current decade, design of dendritic macromolecules including dendrimers and polymers has reached a new era, mainly due to the remarkably successful and elegant synthetic routes that have been developed recently. This survey aims at demonstrating the potential of the Diels,Alder "click" chemistry, a very effective, simple and versatile synthetic tool in the formation of complex and functional nanometer-sized assemblies. The role of retro Diels-Alder reaction is also explored to highlight the increasing competitive potential of this strategy in the design of dendritic macromolecules of topical interest. The potential "green" nature of this methodology in constructing macromolecular assemblies is also evaluated. [source] Diels-Alder Reactions of N -Functionalized Acryloyl , -Pyrrolidone Derivatives Using FeCl3·6H2O as an Efficient Catalyst under Solvent-free ConditionsCHINESE JOURNAL OF CHEMISTRY, Issue 6 2007Wen Pei Abstract Diels-Alder reactions of N -functionalized acryloyl , -pyrrolidone derivatives were investigated, which were catalyzed by FeCl3·6H2O as an efficient catalyst under solvent-free conditions at room temperature. The corresponding cycloadducts with functionalized-pyrrolidone were prepared in high yield with high stereoselectivity by a green chemistry procedure. N -Functionalized acryloyl pyrrolidone derivatives, a kind of pyrrolidone-functionalized chelating ,,, -unsaturated ketone usable as a dienophile in Diels-Alder reaction, were synthesized by N -acylation procedure in ionic liquid as a novel synthetic method. [source] Chiral guanidine catalyzed Michael addition reaction and Diels-Alder reaction of anthrone and N -methylmaleimideCHINESE JOURNAL OF CHEMISTRY, Issue 3 2000Peng Bin Abstract Two chiral guanidines were evaluated as catalysts for the reaction of anthrone (1) with N -methylmaleimide (2). When guanidine 5 was used, the Michael adduct 4 was isolated as a major product. The best enantioselectivity (70% ee) was obtained when the reaction was carried out in THF at -20°C. [source] Concise stereocontrolled routes to fumagillol, fumagillin, and TNP-470CHIRALITY, Issue 2 2003David A. Vosburg Abstract A concise, diastereoselective synthesis of (±)-fumagillol (3) and formal, enantioselective syntheses of the potent angiogenesis inhibitors fumagillin (1) and TNP-470 (2) are reported. The origin of asymmetry is a highly diastereoselective Diels-Alder reaction using a diene with a chiral oxazolidinone auxiliary. The stereochemical course of a key conjugate addition reaction is controlled by the cup-shaped architecture of a cis -fused bicyclic enal. Other key steps include a facile hetero-Claisen rearrangement and a site-selective Sharpless epoxidation. Chirality 15:156,166, 2003. © 2003 Wiley-Liss, Inc. [source] Diels,Alder Reactions of Symmetrically 1,4-Disubstituted Dienes: Theoretical Study on the Influence of the Configuration of the Double Bonds on the Regio- and EndoselectivityEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 18 2008Samira Baki Abstract It was experimentally shown in Diels-Alder reactions that symmetrically 1,4-disubstituted dienes exhibit high regio- and endoselectivity induced by the (E,Z) configuration of the double bonds. In order to understand the origin of this selectivity, the transition states associated with the reaction between a series of such dienes (R = OMe, CH3, NH2, F, CN) on substituted ethylene (R, = CO2Me, CN, F, OMe) were determined by DFT calculations. If the regioselectivity confirmed by a single-point MP2 calculation is predicted to be good in most cases, its direction remains difficult to predict; the R, group of the dienophile can orient itself toward either the (Z) or the (E) side of the diene. Neither primary nor secondary frontier orbital interactions appear to be able to rationalize these results. They are more likely explained by a delicate balance between steric and electrostatic interactions. This hypothesis is further supported by the calculated reactivity of the (E,E) and (Z,Z) corresponding dienes. In any case, a standard DFT calculation, confirmed by a single-point MP2 step, is likely to provide a reliable guideline for a synthesis strategy that allows the control of up to four stereogenic centres in a single reaction step.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Synthesis and Reactivity of , -Electron-Deficient (Arylsulfonyl)acetatesHELVETICA CHIMICA ACTA, Issue 12 2002Diego Different , -electron-deficient (arylsulfonyl)acetates 9 were synthesized (Scheme,1, Table,1), and their behavior as soft nucleophiles in the dialkylation reaction under phase-transfer catalysis conditions was studied (Schemes,2 and 3, Tables,2 and 3). The [3,5-bis(trifluoromethyl)phenyl]sulfonyl group was shown to be the best substituent for the stereoselective synthesis of (E)-aconitates 18via an alkylation hydro-sulfonyl-elimination integrated process under very mild phase-transfer-catalysis conditions (Scheme,5, Table,4). Sulfonylacetates 9h,i also underwent smooth Diels-Alder reactions with acyclic and cyclic dienes via in situ formation of the appropriate dienophile through a Knoevenagel condensation with paraformaldehyde (Scheme,6). Reductive desulfonylation with Zn and NH4Cl in THF was shown to be an efficient method for removal of the synthetically useful sulfonyl moiety (Scheme,7). [source] Access to indoles via Diels-Alder reactions of 2-vinylpyrroles with maleimidesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 6 2009Wayland E. Noland Variously substituted 2-vinylpyrroles underwent an endo -addition [4+2] cycloaddition reaction with maleimides followed by a spontaneous highly diastereoselective (93,98% de) isomerization to give tetrahydroindoles in moderate to excellent yield. Treatment with activated MnO2 in refluxing toluene provided the corresponding indoles in moderate to good yield. This highly convergent methodology for formation of indoles is versatile and the starting materials are conveniently prepared. J. Heterocyclic Chem., (2009). [source] Diels-Alder Reactions of N -Functionalized Acryloyl , -Pyrrolidone Derivatives Using FeCl3·6H2O as an Efficient Catalyst under Solvent-free ConditionsCHINESE JOURNAL OF CHEMISTRY, Issue 6 2007Wen Pei Abstract Diels-Alder reactions of N -functionalized acryloyl , -pyrrolidone derivatives were investigated, which were catalyzed by FeCl3·6H2O as an efficient catalyst under solvent-free conditions at room temperature. The corresponding cycloadducts with functionalized-pyrrolidone were prepared in high yield with high stereoselectivity by a green chemistry procedure. N -Functionalized acryloyl pyrrolidone derivatives, a kind of pyrrolidone-functionalized chelating ,,, -unsaturated ketone usable as a dienophile in Diels-Alder reaction, were synthesized by N -acylation procedure in ionic liquid as a novel synthetic method. [source] | |||||||||||||||||||||||||