نتایج جستجو برای: chemoselective

تعداد نتایج: 1372  

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2008
abbas shockravi esmael rostami davood heidaryan hanif fattahi

zn/acoh on silica gel converts a range of structurally different sulfoxides to their corresponding thioethers in excellent yields under microwave irradiation. it has been found that chemoselective deoxygenation of sufoxides can be achieved in the presence of other reducible functional groups such as acetals, acids, amides,   esters, ketones and nitriles.

Journal: :Journal of the American Chemical Society 2014

Journal: :Chemical & Pharmaceutical Bulletin 2021

Catalytic chemoselective reactions of innately less reactive functionalities over more are described. A cooperative catalyst comprising a soft Lewis acid/hard Brønsted base enabled activation hydroxyl group an amino group, allowing for nucleophilic addition to electron-deficient olefins. The reaction could be applicable variety alcohols, including pharmaceuticals, without requiring tedious prot...

2014
Simone Maschauer Olaf Prante

At the time when the highly efficient [(18)F]FDG synthesis was discovered by the use of the effective precursor 1,3,4,6-tetra-O-acetyl-2-O-trifluoromethanesulfonyl- β -D-mannopyranose (mannose triflate) for nucleophilic (18)F-substitution, the field of PET in nuclear medicine experienced a long-term boom. Thirty years later, various strategies for chemoselective (18)F-labeling of biomolecules h...

2013
Seonghwan Kim Dongkyu Lee Xunchen Liu Charles Van Neste Sangmin Jeon Thomas Thundat

Speciation of complex mixtures of trace explosives presents a formidable challenge for sensors that rely on chemoselective interfaces due to the unspecific nature of weak intermolecular interactions. Nanomechanical infrared (IR) spectroscopy provides higher selectivity in molecular detection without using chemoselective interfaces by measuring the photothermal effect of adsorbed molecules on a ...

2012
Christopher A. Rose Sivaji Gundala Claire-Louise Fagan Johannes F. Franz Stephen J. Connon Kirsten Zeitler

It has been shown for the first time that relatively electron deficient triazolium pre-catalysts promote (at low loadings in the presence of base) highly chemoselective crossed acyloin condensation reactions between aldehydes and a-ketoesters to afford densely functionalized products incorporating a quaternary stereocentre of considerable synthetic potential. Hydroacylation pathways which have ...

Journal: :Journal of combinatorial chemistry 2000
A Golisade J C Bressi S Van Calenbergh M H Gelb A Link

A polymer-assisted solution-phase (PASP) synthesis of lead structure analogues ready for biological testing without the demand for chromatographic purification is described. Carboxylic acids are coupled to the Kenner or Ellman safety catch linker, respectively, activated by methylation or cyanomethylation and subsequently transferred to the 2'-amino group of the 2'-amino-2'-deoxyadenosine scaff...

Journal: :Nucleosides, Nucleotides and Nucleic Acids 2009

Journal: :iranian journal of science and technology (sciences) 2015
s. rezayati

an efficient and chemoselective procedure for the preparation of 1, 1-diacatates (acylals) from various aldehydes with acetic anhydride in the presence of brønsted acidic ionic liquid [msei]cl as a reusable catalytic system under solvent-free condition at room temperature and short periods of times with excellent yields will be described. the catalyst was easily separated in simple work-up and ...

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