نتایج جستجو برای: trimethylsilyl ether
تعداد نتایج: 23149 فیلتر نتایج به سال:
Introdution: Hepatocellular carcinoma (HCC) is one of the most common cancers. It is the third leading cause of cancer related death. This study aimed to evaluate the phytochemical composition of ethanolic and aqueous Glycyrrhiza glabra root extracts its apoptotic effects against human hepatocarcinoma HepG2 cell line. Methods: In the current experimental study, the phyochemical composition of ...
Structurally well-defined bimetallic titanium(IV) (salen) and monometallic vanadium(V) (salen) complexes have been used as catalysts for the asymmetric addition of trimethylsilyl cyanide to β-nitroalkenes to produce chiral nitronitriles with ee values in the range of 79-89 % and conversions up to 100 % at 0 °C. The reaction conditions (solvent, temperature, time and vanadium complex counter-ion...
Calciumand strontium bis[bis(trimethylsilyl)amide] react with bis(trimethylsilyl)arsane in tetrahydrofuran to give the corresponding tetrakis(tetrahydrofuran-O) metal bis[bis(trimethylsilyl)arsanides]. The calcium derivative crystallizes in the triclinic space group P I with a = 1191.7(2), b = 1232.0(2), c = 1655.0(2) pm, a = 102.46(1)°, ß = 107.92(1)°, y = 104.66(1)° and Z = 2, the strontium d...
The trimethylsilyl ethers of alditols with 3, 4, 5 and 6 carbon atoms were investigated. The mass spectra are unusually clearly correlated with the structures. The predominant fragmentations are cleavages in the carbon chain and rearrangement loss of trimethylsilanol. The spectra are closely related to those of the methyl ethers. A spectrum unambiguously identifies a compound as an alditol and ...
An efficient method for the cocyclotrimerization of bicyclic alkenes and benzynes catalyzed by palladium phosphine complexes to give the corresponding norbornane anellated 9,10-dihydrophenanthrene derivatives is described. Bicyclic alkenes 1a-i undergo [2 + 2 + 2] cocyclotrimerization with benzynes generated from precursors 2a-d [2-(trimethylsilyl)phenyl triflate (2a), 4,5-dimethyl-2-(trimethyl...
The rearrangement of tris(trimethylsilyl)silyltrimethylgermane 1 to give tetrakis(trimethylsilyl)germane 2 was investigated as a typical example for Lewis acid catalyzed Wagner-Meerwein-type rearrangements of polysilanes and polygermasilanes. Direct 29Si NMR spectroscopic evidence is provided for several cationic intermediates during the reaction. The identity of these species was verified by i...
Use of high-resolution open tubular glass capillary columns to separate acidic metabolites in urine.
We used high-resolution glass capillary columns to study the trimethylsilyl derivatives of some acidic metabolites found in pooled urine specimens form control and postpartum subjects. About 30 compounds were identified by gas chromatography-mass spectrometry-computer techniques. In general, open tubular capillary columns effect better resolution of trimethylsilyl derivatives of organic acids t...
structurally different trimethyl silyl ethers are oxidized with bu4/nio4 in the presence of alcl3 and bf3 as catalysts in ch3cn and chcl3 under reflux conditions. the corresponding carbonyl compounds are isolated in good yields.
The mechanism by which four Lewis bases, triethylamine, tetrabutylammonium thiocyanate, tetrabutylammonium azide and tetrabutylammonium cyanide, catalyse the addition of trimethylsilyl cyanide to aldehydes is studied by a combination of kinetic and spectroscopic methods. The reactions can exhibit first or second order kinetics corresponding to three different reaction mechanisms. Spectroscopic ...
A new 2-(5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracene-8-yl)-4-(trimethylsilyl)pyridine-based iridium complex was synthesized for efficient solution-processed sky-blue phosphorescent organic light-emitting diodes (PhOLEDs). The effect of dioxaboranaphthoanthracene instead phenyl with the electron-accepting group, as well bulky pyridine trimethylsilyl on ligand investigated. dopant found to have...
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