نتایج جستجو برای: trimethylsilyl ethers

تعداد نتایج: 8562  

Journal: :iranian journal of catalysis 2011
gholamabbas chehardoli mohammad ali zolfigol tahereh azadbakht

1,1’-(ethane-1,2-diyl)dipyridinium bistribromide (edpbt) was used as a chemoselective and effective organocatalyst for the silylation of hydroxyl groups as well as desilylation of trimethylsilyl ethers under mild conditions at room temperature with good to excellent yields.

1,1’-(Ethane-1,2-diyl)dipyridinium bistribromide (EDPBT) was used as a chemoselective and effective organocatalyst for the silylation of hydroxyl groups as well as desilylation of trimethylsilyl ethers under mild conditions at room temperature with good to excellent yields.

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: :Organic & biomolecular chemistry 2013
Zhen-yuan Gu Xiao-tai Zhang Jia-xin Zhang Guo-wen Xing

Based on a preactivation protocol with (p-Tol)2SO/Tf2O, a practical, straightforward, and high-yielding synthesis of α-sialyl C-glycosides was accomplished by coupling N-acetyl-5-N,4-O-oxazolidione protected thiosialoside with various trimethylsilyl enol ethers and allyltrimethylsilanes. High yields and excellent α-selectivities were obtained for the strong π-nucleophiles with large nucleophili...

Journal: :journal of sciences islamic republic of iran 0

trimethylsilylation of a variety of alcohols and phenols, in the presence of silica chloride, using hexamethyldisilazane (hmds) in solution and under solvent-free conditions is reported. trimethylsilyl ethers were formed in excellent yields both for aliphatic alcohols and phenols without having an electron-withdrawing group. in addition, sio2-cl can be recovered and reused after drying.

Journal: :Chemistry 2010
Heiko Rinderhagen Jochen Mattay Rafael Nussbaum Thomas Bally

In contrast to the structurally and configurationally stable alkyl- or aryl-substituted cyclopropyl radical cations, cyclopropyl silyl ethers undergo spontaneous ring opening upon oxidation whereby the endocyclic C-C(O-TMS) bond is cleaved with remarkable selectivity. DFT calculations on 1-trimethylsilyloxybicyclo[4.1.0]heptane show that this selectivity arises from the topology of the potentia...

Journal: :Analytical sciences : the international journal of the Japan Society for Analytical Chemistry 2003
Takashi Iida Keisuke Shiraishi Shoujiro Ogawa Junichi Goto Toshio Nambara

An improved method for a suitable derivatization of polyhydroxylated steroids having one or two tert-hydroxyl groups at the 5beta-, 14alpha-, 17alpha-, 24-, and/or 25-positions by capillary gas chromatography (CGC) is described. By using trimethylsilyl triflate as a silylating reagent and 2,6-lutidine as a catalyst, each of 5beta-cholane and 5alpha-cholestane series of steroids was successfully...

Trimethylsilylation of a variety of alcohols and phenols, in the presence of silica chloride, using hexamethyldisilazane (HMDS) in solution and under solvent-free conditions is reported. Trimethylsilyl ethers were formed in excellent yields both for aliphatic alcohols and phenols without having an electron-withdrawing group. In addition, SiO2-Cl can be recovered and reused after drying.

2001
Zhong Ping TAN Lin WANG Jian Bo WANG

The protection of functional group is unavoidable in multi-step organic synthesis. Along with tetrahydropyranyl (THP) ethers, t-butyldimethylsilyl (TBDMS) ethers have been widely used for protecting hydroxyl groups. TBDMS ether is more stable to hydrolysis than trimethylsilyl ether, but is still readily cleaved by a variety of selective conditions. The deprotection of TBDMS is usually under mil...

Dariush Saberi Farid Rohandeh Khodabakhsh Niknam

Sulfuric acid ([3-(3-silicapropyl)sulfanyl]propyl]ester (SASPSPE) is employed as a recyclable catalyst for the silylation of hydroxyl groups. A good range of primary, secondary alcohols and phenolic hydroxyl groups were effectively converted into their corresponding trimethylsilyl ethers with hexamethyldisilazane in the presence of catalytic amounts of SASPSPE at room temperature with short rea...

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