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Ring Opening (ring + opening)
Kinds of Ring Opening Terms modified by Ring Opening Selected AbstractsChemInform Abstract: Sc(OTf)3 -Catalyzed Smooth Tandem [3 + 2] Cycloaddition/Ring Opening of Donor,Acceptor Cyclopropane 1,1-Diesters with Enol Silyl Ethers.CHEMINFORM, Issue 9 2009Jie Fang 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] Nitrile Anion Cyclization with Epoxysilanes Followed by Brook Rearrangement/Ring Opening of Cyclopropane Nitriles/Alkylation.CHEMINFORM, Issue 47 2004Seigo Okugawa Abstract For Abstract see ChemInform Abstract in Full Text. [source] Ring Opening of 1-Azabicyclo[1.1.0]butanes with Hydrazoic Acid , a Facile Access to N -Unsubstituted Azetidin-3-AminesHELVETICA CHIMICA ACTA, Issue 7 2005Grzegorz Mlosto Sterically congested 1-azabicyclo[1.1.0]butanes 1 add hydrazoic acid smoothly at 0,5°, giving 3-azidoazetidines 2 in good to excellent yields. After hydrogenolysis over Pd/C catalyst, compounds 2 were converted into N -unsubstituted azetidin-3-amines 4. Attempted reduction of 2a with Raney -Ni led to a mixture of the expected azetidin-3-amine 4a and the ring-enlarged 2,5-dihydro-1H -imidazole derivative 5. [source] Asymmetric Ring Opening of Benzo-7-oxabicyclo[2.2.1]heptadienes with Cationic Rhodium ComplexesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2010Angelika Preetz Abstract The efficient design of stereochemically challenging ring systems by ring opening of heterobicyclic alkenes has become a very important reaction in the chemistry of CC and CX bond formation. By using the hitherto applied in situ technique for the generation of the ,2 -bridged, dimeric neutral rhodium complexes, however, the catalytically active species and its concentration remained unidentified. Furthermore, the reaction temperature is at least 80,°C. The application of cationic rhodium(I) solvate complexes (that no longer contain blocking diolefins) shows that a much greater activity and enantioselectivity for the synthesis of 1,2-dihydro-1-naphthols can be reached than was described so far, even at ambient temperature. NMR spectroscopy and X-ray analysis show that a product inhibition during the ring opening reaction takes place that is independent of the nucleophile. [source] Cascade Reactions: Catalytic Synthesis of Functionalized 1,3-Dihydroisobenzofuran and Tetrahydrofuran Derivatives by Sequential Nucleophilic Ring Opening,Heterocyclization, Oxidative Carbonylation of AlkynyloxiranesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 14-15 2009Nicola Della Ca' Abstract Differently substituted alkynyloxiranes were efficiently converted into functionalized 1,3-dihydroisobenzofurans and tetrahydrofuran derivatives in fair to good yields by a new cascade reaction, consisting of a sequential nucleophilic ring opening,heterocyclization,oxidative carbonylation process. Reactions were carried out at 80,100,°C and under a 3:1 mixture of carbon monoxide and air (total pressure=32,42,atm at 25,°C) in methanol or acetonitrile/methanol mixtures in the presence of catalytic amounts of palladium diiodide in conjunction with an excess of potassium iodide. The nucleophilic species beginning the cascade process by regioselective attack to the less hindered carbon of the oxirane ring can be methanol itself or iodide anions. [source] A Proposed Mechanism for the Reductive Ring Opening of the Cyclodiphosphate MEcPP, a Crucial Transformation in the New DXP/MEP Pathway to Isoprenoids Based on Modeling Studies and Feeding ExperimentsCHEMBIOCHEM, Issue 3 2004Wolfgang Brandt Dr. Abstract Experimental and theoretical investigations concerning the second-to-last step of the DXP/MEP pathway in isoprenoid biosynthesis in plants are reported. The proposed intrinsic or late intermediates 4-oxo-DMAPP (12) and 4-hydroxy-DMAPP (11) were synthesized in deuterium- or tritium-labeled form according to new protocols especially adapted to work without protection of the diphosphate moiety. When the labeled compounds MEcPP (7), 11, and 12 were applied to chromoplast cultures, aldehyde 12 was not incorporated. This finding is in agreement with a mechanistic and structural model of the responsible enzyme family: a three-dimensional model of the fragment L271,A375 of the enzyme GcpE of Streptomyces coelicolor including NADPH, the Fe4S4cluster, and MEcPP (7) as ligand has been developed based on homology modeling techniques. The model has been accepted by the Protein Data Bank (entry code 1OX2). Supported by this model, semiempirical PM3 calculations were performed to analyze the likely catalysis mechanism of the reductive ring opening of MEcPP (7), hydroxyl abstraction, and formation of HMBPP (8). The mechanism is characterized by a proton transfer (presumably from a conserved arginine 286) to the substrate, accompanied by a ring opening without high energy barriers, followed by the transfer of two electrons delivered from the Fe4S4cluster, and finally proton transfer from a carboxylic acid side chain to the hydroxyl group to be removed from the ligand as water. The proposed mechanism is in agreement with all known experimental findings and the arrangement of the ligand within the enzyme. Thus, a very likely mechanism for the second to last step of the DXP/MEP pathway in isoprenoid biosynthesis in plants is presented. A principally similar mechanism is also expected for the reductive dehydroxylation of HMBPP (8) to IPP (9) and DMAPP (10) in the last step. [source] ChemInform Abstract: Ring Opening of Cyclic Vinylogous Acyl Triflates Using Stabilized Carbanion Nucleophiles: Claisen Condensation Linked to Carbon,Carbon Bond Cleavage.CHEMINFORM, Issue 37 2010David M. Jones Abstract Treatment of the cyclic triflates (I) and (VII) with carbanion nucleophiles provides acyclic alkynes bearing 1,3-diketone, ,-keto ester, ,-keto phosphonate, or ,-keto phosphine oxide moieties. [source] ChemInform Abstract: Ring Opening of Aziridines with Tetranitromethane in the Presence of Triethylamine.CHEMINFORM, Issue 32 2010-Tosylamino Nitrates., Efficient Synthesis of Abstract Tetranitromethane is used as an oxidant and source of the nitro group. [source] ChemInform Abstract: Studies Toward the Taming of the "Carbocation" in the Regioselective Ring Opening of Epoxides to Allylic Alcohols.CHEMINFORM, Issue 28 2010Helen A. Chapman 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: Al(HSO4)3/Silica Gel as a Novel Catalytic System for the Ring Opening of Epoxides with Thiocyanate Anion under Solvent-Free Conditions.CHEMINFORM, Issue 26 2010Ali Reza Kiasat 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: One-Pot "Click" Reactions: Tandem Enantioselective Biocatalytic Epoxide Ring Opening and [3 + 2] Azide Cycloaddition.CHEMINFORM, Issue 24 2010Lachlan S. Campbell-Verduyn 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: Thiomaleic Anhydride: A Convenient Building Block for the Synthesis of ,-Substituted ,- and ,-Lactones Through Free-Radical Addition, Nucleophilic Ring Opening, and Subsequent Thiocarboxylate Manipulation.CHEMINFORM, Issue 4 2010David Crich 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: Nucleophilic Ring Opening of Epoxides Promoted by Multi-Site Phase-Transfer Catalyst: An Efficient and Eco-Friendly Route to Synthesis of ,-Hydroxy-thiocyanate.CHEMINFORM, Issue 52 2009Ali Reza Kiasat 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 Recognition and Sequential Ring Opening of 2-Substituted-N-nosylaziridines with (DHQD)2AQN and TMSNuCHEMINFORM, Issue 27 2009Satoshi Minakata 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: Stereoselective Formation of Alkenyl Halides via Magnesium Halide Promoted Ring Opening of Bis-Activated Cyclopropenes.CHEMINFORM, Issue 23 2009Yi Wang 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: Microwave-Assisted Gold(I)-Catalyzed Pyran Ring Opening in Brevifloralactone (I): Synthesis of the Hawtriwaic Acid Core.CHEMINFORM, Issue 20 2009Luis D. Miranda 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: Aqueous-Mediated Ring Opening of Epoxides with Oximes: A Rapid Entry into ,-Hydroxy Oxime O-Ethers as Potential ,-Adrenergic Blocking Agents.CHEMINFORM, Issue 44 2008Mohammad Navid Soltani Rad 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 Method for the Ring Opening of Epoxide with Aromatic Amines by Sb(III) Chloride under Microwave Irradiation.CHEMINFORM, Issue 41 2008Dadkhoda Ghazanfari 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: Ring Opening of ,,,-Epoxy Phenyl Ketones with Ceric Ammonium Nitrate (CAN) and Potassium Bromide.CHEMINFORM, Issue 33 2008Zhou Lu 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 Unexpected Triethylbenzylammonium Chloride Catalyzed Ring Opening of 2-Pyrones in the Synthesis of 1-Arylbenzo[f]quinoline-2-carboxamide Derivatives in Aqueous Media.CHEMINFORM, Issue 20 2008Xian-Shan Wang 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 Synthesis of Polyfunctionalized Thiophenes via an Amine-Mediated Ring Opening of EWG-Activated 2-Methylene-1,3-dithioles.CHEMINFORM, Issue 14 2008Fushun Liang 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: Exceptionally Active Yttrium,Salen Complexes for the Catalyzed Ring Opening of Epoxides by TMSCN and TMSN3.CHEMINFORM, Issue 10 2008Biswajit Saha 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 Enantiomerically Pure Tertiary 1,2-Amino Alcohols by the Highly Diastereoselective Reductive Ring Opening of Oxazolidines.CHEMINFORM, Issue 7 2008Philip C. Bulman Page 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: Microwave-Assisted Ring Opening of Epoxides: A General Route to the Synthesis of 1-Aminopropan-2-ols with anti-Malaria Parasite Activities.CHEMINFORM, Issue 1 2008Aelig Robin 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] The High-Temperature Alicyclic Ring Contraction of 1,1-Dichloroperfluorotetralin and the Alicyclic Ring Opening of 1,1-Dichloroperfluorobenzocyclobutene.CHEMINFORM, Issue 45 2007Victor M. Karpov 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] Photochemically Catalyzed Ring Opening of Oxiranecarbonitriles and [3 + 2] Cycloaddition with Olefins: Synthesis of Polysubstituted Tetrahydrofurans.CHEMINFORM, Issue 30 2007Jinhui Pan 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] A Highly Regio- and Chemoselective Synthesis of Vicinal Bromohydrins by Ring Opening of Terminal Epoxides with Dibromoborane,Dimethyl Sulfide.CHEMINFORM, Issue 27 2007Chandra D. Roy 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] Rhodium-Catalyzed Asymmetric Arylative Ring Opening of Bicyclic Hydrazines.CHEMINFORM, Issue 14 2007Ferruccio Bertolini 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] Oxidative Ring Opening of 2,5-Diarylfurans by Selectfluor®.CHEMINFORM, Issue 51 2006Stephen J. Blank 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] A New Approach to the Nazarov Reaction via Sequential Electrocyclic Ring Opening and Ring Closure.CHEMINFORM, Issue 48 2006Tina N. Grant 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] | ||||||||||||||||||||||||||||