نتایج جستجو برای: ethers

تعداد نتایج: 7167  

Journal: :Journal of the American Chemical Society 2004
Benjamin D Sherry F Dean Toste

Homoallenic alcohols are prepared from propargyl vinyl ethers using a trinuclear gold(I)-oxo complex, [(Ph3PAu)3O]BF4, as a catalyst for propargyl Claisen rearrangement at room temperature. The gold(I)-catalyzed reaction is effective for a diverse collection of propargyl vinyl ethers, including substrates containing aryl and alkyl groups at the propargylic position, and hydrogen, aryl, and alky...

Journal: :iranian chemical communication 0
abbas amini manesh payame noor university, hamedan ardeshir khazaei faculty of chemistry, bu-ali sina university, p.o. box 651783868, hamedan, iran maedeh gohari department of chemistry, payame noor university, 19395-4697 tehran, i. r. of iran mahdieh chegeni department of chemistry, faculty of science, ayatollah ozma boroujerdi university, boroujerd, iran shahnaz saednia young researchers & elites club, toyserkan branch, islamic azad university, toyserkan, iran

methoxymethylation of a variety of alcohols was performed using formaldehyde dimethyl acetal in the presence of 1,3-dichloro-5,5-dimethyl hydantoin [dcdmh] and poly n,n′-dibromo-n-ethyl naphthyl-2,7-disulfonamide [pbns] as catalysts at room temperature and under solvent-free conditions. our experiments show that primary and secondary alcohols can be smoothly converted into the corresponding mom...

Journal: :iranian journal of catalysis 2014
farhad shirini masoumeh abedini ahmad nasiri abkenar bita baghernejad

a mild, efficient and fast method for the oxidation of alcohols and trimethylsilyl and tetrahydropyranyl ethers to their corresponding carbonyl compounds using cro3 in the presence of sulfonic acid functionalized ordered nanoporous na+-montmorillonite (sanm) and under solvent-free conditions is reported. all reactions were performed at room temperature in high to excellent yields. ease of the p...

Journal: :Archives of pharmacal research 2003
Young Hoon Jung Ji Duck Kim

We examined the effect of p-substituents in p-substituted cinnamyl methyl ethers and 1-(p-substituted phenyl)allyl methyl ethers with CSI, and confirmed that the CSI reaction of allyl ethers (p-substituted ethers) is a competitive reaction of S(N)i and S(N)1 mechanism according to the stability of the carbocation. And, the only terminal allylic amine was obtained through the migration reaction ...

Journal: :International journal of toxicology 2016
Monice M Fiume Bart Heldreth Wilma F Bergfeld Donald V Belsito Ronald A Hill Curtis D Klaassen Daniel C Liebler James G Marks Ronald C Shank Thomas J Slaga Paul W Snyder F Alan Andersen

The Cosmetic Ingredient Review (CIR) Expert Panel assessed the safety of 131 alkyl polyethylene glycol (PEG)/polypropylene glycol ethers as used in cosmetics, concluding that these ingredients are safe in the present practices of use and concentration described in this safety assessment when formulated to be nonirritating. Most of the alkyl PEG/PPG ethers included in this review are reported to...

Journal: :Chemical communications 2007
Masato Kawamura Kazuhiko Sato

Magnetic nanoparticle (MNP)-supported crown ethers were successfully prepared and evaluated as catalysts for solid-liquid phase-transfer reactions; the catalytic activities of the MNP-supported crown ethers were not inferior to those of non-supported crown ethers; after the reactions, the catalysts could be readily separated using an external magnet and reused without significant loss of cataly...

Journal: :Organic & biomolecular chemistry 2008
Syed Tasadaque A Shah Patrick J Guiry

An efficient and chemoselective cleavage of silyl ethers (primary, secondary and aromatic) by using catalytic quantities of trimethylsilyl bromide (TMSBr) in methanol is reported. A wide range of alkyl silyl ethers such as TBS, TIPS, and TBDPS can be chemoselectively cleaved in high yield in the presence of aryl silyl ethers. The deprotection of silyl esters was also achieved employing catalyti...

Journal: :Journal of the American Chemical Society 2006
Pascal Dubé F Dean Toste

The gold(I)-catalyzed carboalkoxylation of alkynes to form indanone derivatives from readily available ortho-acetylenic benzylic ethers is described. Importantly, the gold(I)-catalyzed rearrangement of enantioenriched benzylic ethers proceeds with chirality transfer, thus providing a practical method for the enantioselective synthesis of indenyl ethers.

Journal: :Molecules 2004
S Servi C Topaloglu

Heteroaryl substituted allyl and homoallyl alcohols were synthesised with two different method. Synthesis of bis-allyl ethers and homoallyl ethers were carried out via reaction of allyl bromide with allyl alcohols and homoallyl alcohols, respectively. [2.3]-Wittig Rearrangement reactions of heteroaryl substituted bis-allyl ethers were investigated using GC/MS techniques. In these reactions two ...

2014
Michael R. Harris Mikhail O. Konev Elizabeth R. Jarvo

Enantioenriched methylenecyclopentanes are synthesized by stereospecific, nickel-catalyzed Heck cyclizations of secondary benzylic ethers. The reaction proceeds in high yield and enantiospecificity for benzylic ethers of both π-extended and simple arenes. Ethers with pendant 1,2-disubstituted olefins form trisubstituted olefins with control of both absolute configuration and alkene geometry. Di...

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