Home About us Contact
|
Home About us Contact | ||
|
|
||
Benzyl Ethers (benzyl + ether)
Selected AbstractsChemInform Abstract: Asymmetric [2,3]-Wittig Rearrangement of Oxygenated Allyl Benzyl Ethers in the Presence of a Chiral Di-tBu-bis(oxazoline) Ligand: A Novel Synthetic Approach to THF Lignans.CHEMINFORM, Issue 5 2010Maria Kitamura 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] A One-Pot Selective Deprotective Acetylation of Benzyl Ethers and OTBDMS Ethers Using the BF3×Et2O,NaI,Ac2O Reagent System.CHEMINFORM, Issue 45 2006Anita Brar 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] Selective Hydrogenolysis of Benzyl Ethers in the Presence of Benzylidene Acetals with Raney Nickel.CHEMINFORM, Issue 39 2006Aurelie Vincent 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] DDQ-Mediated Direct Cross-Dehydrogenative-Coupling (CDC) Between Benzyl Ethers and Simple Ketones.CHEMINFORM, Issue 32 2006Yuhua 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] Novel ZnX2 -Modulated Pd/C and Pt/C Catalysts for Chemoselective Hydrogenation and Hydrogenolysis of Halogen-Substituted Nitroarenes, Alkenes, Benzyl Ethers, and Aromatic Ketones.CHEMINFORM, Issue 49 2003George Wu Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Synthesis and Antimicrobial Activity of Hydroxyalkyl- and Hydroxyacyl-phenols and Their Benzyl Ethers.CHEMINFORM, Issue 30 2002J. Krauss 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] Novel materials for bioanalytical and biomedical applications: Environmental response and binding/release capabilities of amphiphilic hydrogels with shape-persistent dendritic junctions,JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 18 2005Chao Zhu Abstract The binding and release capabilities of a hydrogel series, constructed of hydrophilic poly(ethylene glycol) segments and hydrophobic dendritic junctions [poly (benzyl ether)s], are evaluated in aqueous media. The environmental response of the amphiphilic networks is also tested in water at three pH values: 1.5, 7.0, and 10.1. The highest swelling ratio is observed under acidic conditions and varies between 3.7 and 6.5, depending on the crosslinking density and dendrimer generation. Gel specimens with embedded indicators react within 3,6 s with a clear color switch to the change in the pH of the surrounding medium. The experiments with model anionic and cationic indicators and stains show that the hydrogels have basic interiors. The gel binding capabilities depend on the water solubility of the substrate and on the size of the incorporated dendritic fragments. Model release studies have been performed at 37 °C and pHs 1.5, 7.0, and 10.1. The observed phenomena are explained by the transformations in the structure and charge that both the networks and the model compounds undergo with the changes in the pH of the aqueous medium. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4017,4029, 2005 [source] Glycosylations Directed by the Armed-Disarmed Effect with Acceptors Containing a Single Ester GroupEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 23 2007Thomas H. Schmidt Abstract A selective glycosylation reaction controlled by the armed-disarmed effect is described by the use of phenyl thioglycosides. The donor thioglycoside is fully protected with benzyl ethers while the acceptor thioglycoside contains benzyl ethers at position 2 and 3 and a strongly electron-withdrawing pentafluorobenzoate ester group at position 6. The coupling can be performed with galactose, glucose, mannose, and phthalimide-protected glucosamine to afford the corresponding 1,4-linked disaccharides in good yield. These disaccharides can act as glycosyl donors for an additional coupling reaction in the same pot if another acceptor and more promoter are added. In this way, two consecutiveglycosylations can be achieved to afford trisaccharides in one operation. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Synthesis and Optoelectronic Properties of Nonpolar Polyrotaxane Insulated Molecular Wires with High Solubility in Organic Solvents,ADVANCED FUNCTIONAL MATERIALS, Issue 21 2008Michael J. Frampton Abstract Hydrophilic polyanionic conjugated polyrotaxanes are readily synthesized in water by Suzuki coupling, but their high polarity and ionic nature limit the potential applications of these materials. Here, we demonstrate three methods for transforming these polar polyelectrolytes into nonpolar lipophilic insulated molecular wires. A water-soluble polyfluorene- alt -biphenylene ,-cyclodextrin (CD) polyrotaxane was converted into nonpolar derivatives by methylation of the carboxylic acid groups with diazomethane and conversion of the hydroxyl groups of the CDs to benzyl ethers, trihexylsilyl ethers, benzoyl esters, and butanoate esters to yield polyrotaxanes that are soluble in organic solvents such as chloroform and cyclohexane. Elemental analysis, NMR spectroscopy, and gel permeation chromatography (GPC) data support the proposed structures of the organic-soluble polyrotaxanes. The extents of reaction of the polyrotaxane CD hydroxyl groups were 55% for trihexylsilyl chloride/imidazole; 81% for benzyl chloride/sodium hydride; 72% for benzoyl chloride/pyridine/4-dimethylaminopyridine; and 98% butanoic anhydride/pyridine/4-dimethylaminopyridine. Alkylation, silylation, and esterification increase the bulk of the encapsulating sheath, preventing interstrand aggregation, increasing the photoluminescence efficiency in the solid state and simplifying the time-resolved fluorescence decay. The organic-soluble polyrotaxanes were processed into polymer light-emitting diodes (PLEDs) from solution in nonpolar organic solvents, thereby excluding ionic impurities from the active layer. [source] Preparation of Imidazolin-2-iminato Molybdenum and Tungsten Benzylidyne Complexes: A New Pathway to Highly Active Alkyne Metathesis CatalystsCHEMISTRY - A EUROPEAN JOURNAL, Issue 29 2010Birte Haberlag Dipl.-Chem. Abstract The reaction of [PhCMBr3(dme)] (dme=1,2-dimethoxyethane) with the hexafluoro- tert- butoxides LiX or KX [X=OC(CF3)2Me] afforded the benzylidyne complexes [PhCMX3(dme)] (2,a: M=W, 2,b: M=Mo), which further reacted with the lithium reagent Li(ImtBuN), generated with MeLi from 1,3-di- tert -butylimidazolin-2-imine (ImtBuNH), to form the imidazolin-2-iminato complexes [PhCMX2(ImtBuN)] (3,a: M=W, 3,b: M=Mo). The propylidyne complex [EtCMoX2(NImtBu)] (4) was obtained by treatment of 3,b with an excess of 3-hexyne. Complexes 3,a and 3,b are able to efficiently catalyse alkyne cross metathesis of various 3-pentynyl benzyl ethers 5 and benzoic esters 7 at room temperature, to afford 2-butyne and the corresponding diethers 6 and diesters 8. The tungsten complex 3,a proved to be a superior catalyst for ring-closing alkyne metathesis, and the [10]cyclophanes 10 and 12 were synthesised in high yield from 1,3-bis(3-pentynyloxymethyl)benzene (9) and bis(3-pentynyl) phthalate (11), respectively. The molecular structures of compounds 2,a, 2,b, 3,a, 3,b, 4, and 12 were determined by single-crystal X-ray diffraction. DFT calculations have been carried out for catalyst systems based on the imidazolin-2-iminato tungsten and molybdenum complexes 3,a and 3,b by choosing the alkyne metathesis of 2-butyne as the model reaction; the studies revealed a lower activation barrier for the tungsten system. [source] | |||||||||||||