نتایج جستجو برای: trimethylsilyl ether

تعداد نتایج: 23149  

Journal: :Journal of environmental sciences 2007
Yi-Qi Zhou Zi-Jian Wang Ning Jia

N,O-bis(trimethylsily)trifluoroacetamide (BSTFA) and N-methyl-N(trimethylsily) trifluoroacetamide (MSTFA) are common derivatization reagents used in the GC-MS analysis of estrogen steroids such as estrone (El) and 17alpha-ethinylestradiol (EE2). In this study, three trimethylsilyl (TMS) steroid derivatives, mono- and di-trimethylsilyl EE2 and mono-trimethylsilyl E1, were observed during the der...

Journal: :iranian journal of catalysis 2015
farhad shirini masoumeh abedini mahnaz shamsi-sani mohadeseh seddighi

a mild, efficient and fast method for the oxidation of alcohols and trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers to their corresponding carbonyl compounds using cro3 in the presence of rice husk ash (rha) is reported. all reactions were performed at room temperature in high to excellent yields. a new, efficient and green catalyst, heterogeneous reaction conditions, easy work-up of...

Journal: :Journal of the American Chemical Society 2008
Hua Lu Jianjun Cheng

We report a new strategy that uses N-trimethylsilyl (N-TMS) amine to mediate controlled ring-opening polymerization of amino acid N-carboxyanhydrides (NCAs). This polymerization proceeds via a unique, trimethylsilyl carbamate (TMS-CBM) propagating group that results from the cleavage of the Si-N bond of N-TMS amine followed by NCA ring opening. Propagation of the polypeptide chains proceeds thr...

2005
JIAN CHEN

Food sources,mineral redistribution, and excreta are someof theways ants enrich their mound environment. Phosphorus excretion has not been reported in red imported Þre ants, Solenopsis invicta Buren. QuantiÞcation of phosphoric acid in worker fecal droplets and larval anal liquid of S. invicta was performed. Phosphoric acid was trimethylsilylated using N,O-bis(trimethylsilyl)trißuoroacetamide, ...

2013
Hans Bock Sabine Nick Christian Näther Klaus Ruppert

From the electron and proton transfer equilibria network of quinones in solution a novel intermediate can be prepared by deprotonation of 2,5-bis(trimethylsilyl)hydroquinone to its monoanion using sodium metal. The sodium salt crystallizes in polymer strings connected via 0 e (H )0 hydrogen bridges, which are capped additionally by twofold dimethoxy-ethanesolvated Na® countercations. The single...

2012
Mojtaba Ziaee Morteza Samini Mohammad Bolourtchian Mohammad Ghaffarzadeh Maryam Ahmadi Mohammad Ali Egbal Arash Khorrami Sina Andalib Nasrin Maleki-Dizaji Alireza Garjani

Fibrates, as hypolipidemic drugs known as agonists of peroxisome proliferator-activated receptors, diminish inflammatory responses. Studies have shown that incorporation of a silicon atom into a drug structure improves its pharmacological potency, modifies its selectivity toward a given target, or changes its metabolic rate, in addition to increasing the lipophilicity of the compounds. A silico...

Journal: :Chemistry 2014
Santiago Martín Gorka Pera Luz M Ballesteros Adam J Hope Santiago Marqués-González Paul J Low Francesc Pérez-Murano Richard J Nichols Pilar Cea

Langmuir films of 4-{[4-({4-[(trimethylsilyl)ethynyl]phenyl}ethynyl)phenyl]ethynyl} benzenaminium chloride ([1 H]Cl) undergo anion metathesis when assembled on an aqueous auric acid (HAuCl4 ) subphase. Subsequent transfer to solid supports gives well-formed Langmuir-Blodgett (LB) monolayers of [1 H]AuCl4 in which the trimethylsilyl group serves as the surface contacting group. Photoreduction of...

Journal: :Angewandte Chemie 2015
Appi Reddy Mandhapati Salla Rajender Jonathan Shaw David Crich

The preparation of a crystalline, peracetyl adamantanyl thiosialoside donor protected by an isothiocyanate group is described. On activation at -78 °C in the presence of typical carbohydrate acceptors, this donor gives high yields of the corresponding sialosides with exquisite α-selectivity. The high selectivity extends to the 4-O-benzyl-protected 3-OH acceptors, which are typically less reacti...

Journal: :Chemical communications 2011
Marissa A Caldwell Aaron E Albers Seth C Levy Teresa E Pick Bruce E Cohen Brett A Helms Delia J Milliron

A general, efficient method is demonstrated for exchanging native oxyanionic ligands on inorganic nanocrystals with functional trimethylsilylated (TMS) chalcogenido ligands. In addition, newly synthesized TMS mixed chalcogenides leverage preferential reactivity of TMS-S bonds over TMS-O bonds, enabling efficient transfer of luminescent nanocrystals into aqueous media with retention of their opt...

Journal: :Tetrahedron letters 2009
Tsung-Hao Fu Amy Bonaparte Stephen F Martin

A variety of heterocyclic alcohols and acetates were coupled with silyl ketene acetals and other π-nucleophiles in the presence of trimethylsilyl trifluoromethanesulfonate to provide an array of substituted β-heteroaryl propionates, including those with contiguous quaternary centers, as well as vinylogs thereof. This reaction also proceeds with high diastereoselectivity when the π-nucleophile b...

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