نتایج جستجو برای: bf3 detector

تعداد نتایج: 59041  

Journal: :The Journal of organic chemistry 2007
Changkun Li Jianbo Wang

The BF3.OEt2-catalyzed Friedel-Crafts propargylation of aromatic compounds with O-propargyl trichloroacetimidates is highly efficient and affords 1,3-diarylpropyne derivatives in good yields.

Journal: :Chemical communications 2003
Hongda Zhao Brian L Pagenkopf

The stereospecific and regioselective C(3) alkynylation of trisubstituted epoxides has been achieved with lithium alkynyl trimethylaluminium ate complexes in the presence of BF3 x OEt2.

Journal: :Chemical communications 2014
Liye Fu Lingyao Li Jun Wang Kyle Knickelbein Lin Zhang Ian Milligan Yi Xu Kylie O'Hara Lindsay Bitterman Wenjun Du

The synthesis of clickable polysaccharides was achieved by using alkynylated 1,6-anhydro glucopyranose as a monomer and BF3·OEt2 as an effective catalyst. Subsequent click conjugation with polyethylene glycol (PEG) afforded PEG-grafted polysaccharides in nearly quantitative efficiency.

Journal: :EPJ Techniques and Instrumentation 2023

Abstract At the 5.5 MV Tandem T11/25 Accelerator Laboratory of NCSR “Demokritos” quasi-monoenergetic neutron beams can be produced in energy ranges ∼15–21 MeV by means 3 H(d,n) 4 He reaction, ∼4–11 via 2 ∼2.0–5.3 using H(p,n) reaction and ∼120–650 keV 7 Li(p,n) Be reaction. The maximum flux has been determined to order $10^{5}\text{--}10^{6}\text{ n/cm}^{2}\text{s}$ <mml:math xmlns:mml="http://...

Journal: :Organic & biomolecular chemistry 2005
Hideki Ishii Sergei V Dzyuba Koji Nakanishi

The lactone rings of ginkgolide A are converted into corresponding tetrahydrofuran moieties via DIBAL-H reduction followed by deoxygenation of the formed lactols with Et3SiH-BF3.Et2O to produce a series of lactone-free ginkgolides.

Journal: :Chemical communications 2004
Dongbin Zhao Zhaofu Fei C André Ohlin Gabor Laurenczy Paul J Dyson

A series of 'dual-functionalised' ionic liquids, comprising imidazolium cations with various functionalities and the nitrile functionalised anion [CH3CH(BF3)CH2CN]- have been prepared; some exhibit very low viscosities-a highly valuable property in many applications.

2017
S. Lashkari S.K. Jensen

Fatty acids are commonly analysed by gas chromatography as their corresponding fatty acid (FA) methyl esters (FAME). For quantitative determination of individual FA an internal standard like C17:0 is necessary. Conjugated FA and polyunsaturated fatty acid (PUFA) represents a challenge in the methylation steps, as they are sensitive to pH changes and oxidation. The present study was carried out ...

2012
Ling Dang Qiang Li Tongmei Ma Sheng Sheng Wei Zeng

An efficient BF3·Et2O-promoted benzylation of arenes and heteroarenes with various benzyl ether derivatives has been developed. This method provided alternative access to valuable diarylmethane in good yields under mild conditions via an easy work-up procedure.

Bahareh Sadeghi, Hamid Reza Molaei

Microwave assisted reactions have gained considerable attention, due to versatility and reduction ofsolvent and reaction time. The reaction of a nano-coconut shell and boron tri-fluoride in diethylether solvent resulted in preparation of nano-coconut shell-BF3 as a catalyst. The nano-coconutshell-BF3 catalyst has been characterized by fourier transform infrared spectroscopy (F...

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