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Expedient Synthesis (expedient + synthesis)
Selected AbstractsAn Expedient Synthesis of Perfluorinated Tetraazamacrocycles: New Ligands for Copper-Catalyzed Oxidation under Fluorous Biphasic ConditionsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 20 2006Augustin de Castries Abstract Conjugate additions of cyclam to perfluorohexyl vinyl sulfone and sulfoxide, which act as efficient fluorous Michael acceptors, readily give access to new fluoro-ponytail tetraazamacrocycles in good yields. The solubility of the N -tetrasubstituted macrocycles depends dramatically on the nature of the polar function (SO or SO2): the sulfoxide cyclam derivative is soluble in perfluorodecaline (pfd) and perfluoromethylcyclohexane (pfmc) while the sulfonyl derivative is almost insoluble in organic or fluorous solvents. In agreement with the well known affinity of cyclam for copper(II) ions, stable copper complexes of the fluorous macrocyclic ligands have been isolated and characterized. In chloroform/methanol, complexes with four perfluorinated tails have been obtained from reaction of the tetra- N -perfluorohexylsulfinyl-substituted macrocycle with copper nitrate and copper perfluorocarboxylate. In trifluoroethanol, a selective retro-Michael reaction has been observed and the same reaction specifically gives copper complexes of the tri- N -substituted macrocycle. Complexes with three and four fluorous tails associated with perfluorocarboxylate counteranions are soluble in fluorous solvents (pfd and pfmc). These copper complexes were tested as catalysts for the oxidation of cyclohexene by molecular oxygen in the presence of tert -butyl hydroperoxide (tbhp). The oxidation reactions proceed under fluorous biphasic conditions and the catalyst can be recovered and reused. Quenching experiments indicate that cyclohexenyl hydroperoxide is the main oxidation product of the reaction performed with or without tbhp. Interestingly, these perfluorinated copper complexes are good, recyclable catalysts for the oxidation of cyclohexene by molecular oxygen without tbhp at room temperature and 65 °C.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Expedient Synthesis of Functionalized Conjugated Enynes: Palladium-Catalyzed Bromoalkynylation of Alkynes,ANGEWANDTE CHEMIE, Issue 19 2010Yibiao Li Von der gleichen Seite: Die direkte cis -Addition von Bromalkinen 1 an Alkine 2 in Gegenwart eines Palladium(II)-Katalysators ergibt difunktionalisierte Enine 3 als Produkte. Die Methode bietet einen einfachen Zugang zu Bromalkeninen. Ein ungewöhnlicher Reaktionsmechanismus wird vorgeschlagen. [source] Expedient Synthesis of (,)-Amphidinolide,X,ANGEWANDTE CHEMIE, Issue 31 2009Hoon Jung Spezifische Cyclisierungen: Die Totalsynthese von (,)-Amphidinolid,X gelang mithilfe der SmI2 -vermittelten 5- exo -Cyclisierung eines Aldehydo-,-alkoxyvinylsulfoxids und einer Ringschlussmetathese als Schlüsselschritten (siehe Schema; Tol = Tolyl). [source] ChemInform Abstract: Alkynes as Equivalents of ,-Diazo Ketones in Generating ,-Oxo Metal Carbenes: A Gold-Catalyzed Expedient Synthesis of Dihydrofuran-3-ones.CHEMINFORM, Issue 31 2010Longwu Ye 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: Base-Catalyzed Conjugate Addition of Thiols to Indolyl Acrylic Acids and in situ Decarboxylation: An Expedient Synthesis of Functionalized 3-(1-Thio)ethyl-1H-indoles.CHEMINFORM, Issue 17 2010Shijay Gao 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: Cu- and Mo-Catalyzed Expedient Synthesis of Alkynyl-Substituted Derivatives of 1,2-Dihydropyridines, -quinolines and -isoquinolines.CHEMINFORM, Issue 2 2010Gullapalli Kumaraswamy 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: Expedient Synthesis of 3-Alkoxymethyl- and 3-Aminomethyl-pyrazolo[3,4-b]pyridines.CHEMINFORM, Issue 22 2009Gregory L. Beutner 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: Expedient Synthesis of Glycidonitriles by Darzens Condensation of ,-Halogenonitriles with Aldehydes and Ketones.CHEMINFORM, Issue 4 2008A. Jonczyk 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] A Practical and Expedient Synthesis of 2-Heterocycle (C,N Bond) Substituted 4-Oxo-4-arylbutanoates.CHEMINFORM, Issue 31 2007Xiaojun Han 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] Expedient Synthesis of Substituted (S)-N-(,-Methylbenzyl)aziridines.CHEMINFORM, Issue 4 2007Sean P. Bew 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] Expedient Synthesis of Chiral 1,2- and 1,4-Diamines: Protecting Group Dependent Regioselectivity in Direct Organocatalytic Asymmetric Mannich Reactions.CHEMINFORM, Issue 42 2006Naidu S. Chowdari 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] Expedient Synthesis of 2-Carboethoxy-4-methylnaphthalenes.CHEMINFORM, Issue 23 2006Chandan P. Amonkar 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] Electrophilic Activation of Lactams with Tf2O and Pyridine: Expedient Synthesis of (.+-.)-Tetraponerine T4.CHEMINFORM, Issue 14 2006Andre B. Charette 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] An Expedient Synthesis of an Isofervenulin Analogue.CHEMINFORM, Issue 52 2004Andrew Bach Abstract For Abstract see ChemInform Abstract in Full Text. [source] General Microwave-Assisted Protocols for the Expedient Synthesis of Quinoxalines and Heterocyclic Pyrazines.CHEMINFORM, Issue 39 2004Zhijian Zhao Abstract For Abstract see ChemInform Abstract in Full Text. [source] Potassium Hydrogen Sulfate-Catalyzed Reactions of Indoles: A Mild, Expedient Synthesis of Bis-indolylmethanes.CHEMINFORM, Issue 33 2004Rajagopal Nagarajan Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Dry Reaction of Indoles with Carbonyl Compounds on Montmorillonite K10 Clay: A Mild, Expedient Synthesis of Diindolylalkanes and Vibrindole A.CHEMINFORM, Issue 37 2002Manas Chakrabarty 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: Expedient Synthesis of Corroles by Oxidant-Mediated, Direct .alpha±alpha., Coupling of Tetrapyrromethanes.CHEMINFORM, Issue 2 2001Jae-Won Ka 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] An Expedient Synthesis of the Repeating Unit of the Acidic Polysaccharide of the Bacteriolytic Complex of Lysoamidase,CHEMISTRY - A EUROPEAN JOURNAL, Issue 3 2005Remy E. J. N. Litjens Abstract The first synthesis of the trisaccharide repeating unit of the acidic polysaccharide of the bacteriolytic complex of lysoamidase is presented. The construction is based on a linear glycosylation strategy that starts from the reducing end and employs thio- and selenoglycosides in a highly stereoselective manner by a single set of activation conditions. The thus-formed trisaccharide is selectively deprotected and oxidised, after which a final deprotection step furnishes the desired repeating unit. [source] An expedient synthesis of novel, fused pyrimido[4,5- d]pyrimidine and pyrimido [5,4- e] [1,2,4]triazolo[4,3- c]pyrimidine analogues from 4-amino-2,6-dichloro-pyrimidineHETEROATOM CHEMISTRY, Issue 4 2006Pratibha Sharma A number of potent pyrimido[4,5-d]pyrimidine have efficiently been synthesized by the condensation of 4-amino-2,6-dichloropyrimidine with various substituted benzaldehyde followed by cyclization with ammonium thiocyanate. Also, these newly synthesized derivatives were utilized for the construction of novel pyrimido[5,4-e][1,2,4]triazolo[4,3-c]pyrimidine analogues via oxidative cyclization involving 1,5-hydrogen abstraction. Structure of all the newly constructed derivatives was corroborated by the elemental and spectral data. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:245,253, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20177 [source] A New Approach to Pyrrolocoumarin Derivatives by Palladium-Catalyzed Reactions: Expedient Construction of Polycyclic Lamellarin ScaffoldADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Lei Chen Abstract A new and efficient protocol for straightforward synthesis of chromeno[3,4- b]pyrrol-4(3H)-one derivatives by palladium-catalyzed sequential coupling/cyclization reactions has been developed. The key strategy relies on creation of pyrrole ring through palladium-catalyzed intramolecular hydroamination of related acetylenic aminocoumarins. The synthetic utility of the obtained chromeno[3,4- b]pyrrol-4(3H)-one product has been demonstrated by the expedient synthesis of polycyclic lamellarin scaffold in four steps. It provides a new entry to synthesis of potentially valuable lamellarin analogues. [source] An expedient synthesis of an isofervenulin analogueJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 4 2004Andrew Bach An efficient approach has been developed for the synthesis of an isofervenulin analogue 1 employing a one-pot condensation-substitution reaction of a chlorocarboethoxytriazine (electrophile) with a urea (nucleophile). The resulting cyclization reaction resulted in the synthesis of a pyrimido-heterocycle in good yield in either acidic or basic media. The former was assisted by utilizing trimethylsilyl chloride. [source] An expedient synthesis of 2,3-dihydro-5,6-dimethoxy-3-methylsulfonamido-1,2-benzisothiazole-1,1-dioxide via intramolecular sulfamoyl michael additionJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 1 2000J. P. Bassin A simple method of introducing a sulfamoylmethyl group on carbon-3 in 1,2-benzisothiazole-1,1-dioxide is described. [source] Microwave-assisted derivatization of cellulose in an ionic liquid: An efficient, expedient synthesis of simple and mixed carboxylic estersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2010Shirley Possidonio Abstract Microwave (MW)-assisted cellulose dissolution in ionic liquids (ILs) has routinely led either to incomplete biopolymer solubilization, or its degradation. We show that these problems can be avoided by use of low-energy MW heating, coupled with efficient stirring. Dissolution of microcrystalline cellulose in the IL 1-allyl-3-methylimidazolium chloride has been achieved without changing its degree of polymerization; regenerated cellulose showed pronounced changes in its index of crystallinity, surface area, and morphology. MW-assisted functionalization of MCC by ethanoic, propanoic, butanoic, pentanoic, and hexanoic anhydrides has been studied. Compared with conventional heating, MW irradiation has resulted in considerable decrease in dissolution and reaction times. The value of the degree of substitution (DS) was found to be DSethanoate > DSpropanoate > DSbutanoate. The values of DSpentanoate and DShexanoate were found to be slightly higher than DSethanoate. This surprising dependence on the chain length of the acylating agent has been reported before, but not rationalized. On the basis of the rate constants and activation parameters of the hydrolysis of ethanoic, butanoic, and hexanoic anhydrides in aqueous acetonitrile (a model acyl transfer reaction), we suggest that this result may be attributed to the balance between two opposing effects, namely, steric crowding and (cooperative) hydrophobic interactions between the anhydride and the cellulosic surface, whose lipophilicity has increased, due to its partial acylation. Four ethanoate-based mixed esters were synthesized by the reaction with a mixture of the two anhydrides; the ethanoate moiety predominated in all products. The DS is reproducible and the IL is easily recycled. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 48: 134,143, 2010 [source] | ||||||||||||||||||||||