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Halogen Exchange (halogen + exchange)
Selected AbstractsChemInform Abstract: General, Regiodefined Access to ,-Substituted Butenolides Through Metal,Halogen Exchange of 3-Bromo-2-silyloxyfurans.CHEMINFORM, Issue 9 2009Efficient Synthesis of an Antiinflammatory Gorgonian Lipid. 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] Confirmation and Prevention of Halogen Exchange: Practical and Highly Efficient One-Pot Synthesis of Dibromo- and Dichloropyridazinones.CHEMINFORM, Issue 13 2007Ji Zhang 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] Preparation of Chiral Homoannularly Bridged N,P-Ferrocenyl Ligands by Intramolecular Coupling of 1,5-Dilithioferrocenes and Their Application in Asymmetric Allylic Substitution Reactions,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 33 2007Shin-ichi Fukuzawa Abstract Homoannularly bridged ferrocene 6b was prepared by intramolecular coupling of 1,5-dilithioferrocene 5b mediated by Fe(acac)3. Dilithioferrocene 5b was prepared by lithium,halogen exchange of the corresponding diiodide, which was prepared by 1,5-dilithiation of the o -TMS-blocked ferrocene and followed by trapping with iodine and removal of the TMS group. Alternatively, 5b could be readily prepared by the reaction of o -bromophenylferrocene 8 with nBuLi (>2 equiv.). The benzene ring of 6b underwent ortho lithiation with tBuLi, and the resulting lithiated species was trapped with Ph2PCl to produce corresponding aminophosphane 7d. Aminophosphane 13, which has the phosphanyl group on the cyclopentadienyl ring, was prepared by intramolecular coupling of 1,5-dilithiated PhPPFA 11 mediated by Fe(acac)3. New N,P ligands 7d and 13 were used in the palladium-catalyzed allylic alkylation and amination of 1,3-diphenyl-2-propenyl acetate (14), and ligand 7d was found to give good yields with enantioselectivities as high as 96,% ee. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Fast and efficient tritium labelling of the nonsteroidal anti-inflammatory drugs naproxen, tolmetin, and zomepiracJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 8 2005Steen K. Johansen Abstract Fast and efficient tritium labelling of the nonsteroidal anti-inflammatory drugs naproxen, tolmetin and zomepirac is reported. Naproxen along with its (R)-enantiomer were labelled by catalytic tritium,halogen exchange of the corresponding 5-bromo derivatives providing [3H]naproxen with a specific activity of 25.4 Ci/mmol. Tolmetin and zomepirac were labelled by the hydrogen isotope exchange reaction using Crabtree's catalyst. This provided [3H]tolmetin and [3H]zomepirac with specific activities of 80.8 and 64.3 Ci/mmol, respectively. All compounds were obtained in high radiochemical purity (>98%). Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||