نتایج جستجو برای: silylation

تعداد نتایج: 439  

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2005
G K Surya Prakash Chulsung Bae Golam Rasul George A Olah

Electrophilic triethylsilylation of diphenylketene leads to exclusive C-silylation giving the diphenyl(triethylsilyl)acetyl cation in the solution phase even though density functional theory calculations at the B3LYP/6-311+G* level indicate that the O-silylation of diphenylketene is preferred over C-silylation by 5.4 kcal/mol in the gas phase. On the other hand, in the case of the parent ketene...

Journal: :Chemistry 2022

A single clean, good-yielding, environment-friendly microwave-assisted procedure for O-silylation of uridine with tert-butyldimethylsilyl chloride (TBDMSCl), 1,8-Diazabicyclo(5.4.0)undec-7-ene (DBU) and potassium nitrate as catalyst under solvent-free conditions is reported. Subsequent silyl ether deprotection accomplished a reusable acidic resin via microwave irradiation. Both the silylation d...

In the presence of magnesium and hexamethylphosphorictriamide, HMPT, trimethylchlorosilane, TMS-C1, reacts with cyanoepoxides to give related compounds. Ring cleavage at ? - position of cyanoepoxide, 1, followed by the addition of two trimethylsilyl groups leads to 2 then substitution of OSiMei by trimethylsilyl or H takes place to give ?, ? - bis (trimethylsilyl) nitrile or ? - trimethyls...

2008
Marie BALÍKOVÁ Vera MARESOVÁ Vilma HABRDOVÁ

A GC/MS method suitable to conduct practical toxicological analyses of unspecified opiates including hydrocodone or hydromorphone is presented. Silylation can be a convenient reaction to derivatize unknown analytes in toxicological samples. However, silylation of drugs with tautomeric keto/enol groups in molecular structure can cause analytical problems due to poor reproducibility. After using ...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 1996
habib firouzabadi zohreh khayat ali reza sardarian shahram tangestaninejad

metalloporphirins; cu(tpp), mn(tpp)cl, co(tpp), fe(tpp)cl, zn(tpp) and mn(obp)cl catalyze region and chemoselective silylation of hydroxyl groups with hmds. fe(tpp)cl is the most effective catalyst and silylation occurs immediately in its presence at room temperature.

Journal: : 2022

Dehydrogenative silylation, which produces vinyl silanes, was generally regarded as a side reaction in hydrosilylation of alkenes. However, due to utility transition-metal catalyzed dehydrogenative silylations have been developed. This mini-review focuses on recent developments manganese-catalyzed selective silylation

Journal: :Chemistry 2010
Ahmed Yahia Polly L Arnold Jason B Love Laurent Maron

A theoretical investigation of the reductive oxo-group silylation reaction of the uranyl dication held in a Pacman macrocylic environment has been carried out. The effect of the modeling of the Pacman ligand on the reaction profiles is found to be important, with the dipotassiation of a single oxo group identified as a key component in promoting the reaction between the Si-X and uranium-oxo bon...

Ali Reza Sardarian Habib Firouzabadi Shahram Tangestaninejad Zohreh Khayat

Metalloporphirins; Cu(TPP), Mn(TPP)Cl, CO(TPP), Fe(TPP)Cl, zn(TPP) and Mn(OBP)Cl catalyze region and chemoselective silylation of hydroxyl groups with HMDS. Fe(TPP)Cl is the most effective catalyst and silylation occurs immediately in its presence at room temperature.

Journal: :Bioresources 2022

Silylation is an effective means of cellulose modification. However, the condensation reaction process between hydrolysis products silane coupling agent and cellulose, as well structure coating, which both have a strong influence on wettability, are still controversial. In this paper, reactions different methyltriethoxysilane with were simulated via density functional theory method. The activit...

Journal: :Chemical communications 2007
Akihiro Ooguri Zenichi Ikeda Seijiro Matsubara

Treatment of thiol ester with bis(iodozincio)alkane in the presence of palladium catalyst followed by silylation affords Z-silyl enol ether chemo-, regio- and stereoselectively.

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