نتایج جستجو برای: syntheses

تعداد نتایج: 11788  

2014
Johannes Ermert

This brief review gives an overview of newer developments in (18)F-chemistry with the focus on small (18)F-labelled molecules as intermediates for modular build-up syntheses. The short half-life (<2 h) of the radionuclide requires efficient syntheses of these intermediates considering that multistep syntheses are often time consuming and characterized by a loss of yield in each reaction step. R...

1999
Guncheol Kim Hyun Woong Hong Sang Hee Lee

The structure of anisomycin has been determined by X-ray investigation4 and the absolute configuration was confirmed by chemical correlation.5 Anisomycin has attracted considerable synthetic interest, and several synthetic studies, derivative syntheses as well as total syntheses, have been reported.6 Especially, the synthesis of its analogues has revealed the structure-activity relationship of ...

Journal: :Journal of the American Chemical Society 2008
Bradley L Nilsson Larry E Overman Javier Read de Alaniz Jason M Rohde

Total syntheses of (+)-nankakurine A (2) and (+)-nankakurine B (3) were accomplished by a sequence that employs an intramolecular dipolar cycloaddition of an azomethine imine intermediate to form the azatricyclic moiety and establish the relative configuration of the spiropiperidine ring. These syntheses, together with the synthesis of the originally purported structure 1 of nankakurine A, rigo...

Journal: :Bioconjugate chemistry 2002
Alexei Toutchkine Perihan Nalbant Klaus M Hahn

The cyanine dyes Cy3 and Cy5 have proven valuable in numerous applications involving conjugation with proteins. Practical syntheses of lysine-selective, succinimidyl ester derivatives of these dyes have been published, and succinimidyl esters are commercially available. However, the published syntheses of cysteine-selective derivatives produce relatively low yields from expensive starting mater...

Journal: :Journal of the American Chemical Society 2005
Phil S Baran Jeremy M Richter

The first total syntheses of welwitindolinone A and the most complex members of the fischerindole family, fischerindoles I and G, are reported. Highlights of these short, protecting-group-free syntheses include the application of the recently developed direct indole-carbonyl coupling, a simple approach for installing the quaternary center with neighboring chlorine atom, a regioselective dehydro...

Journal: :The Journal of organic chemistry 2009
Seung-Mann Paek Hwayoung Yun Nam-Jung Kim Jong-Wha Jung Dong-Jo Chang Sujin Lee Jakyung Yoo Hyun-Ju Park Young-Ger Suh

Highly concise syntheses of (+)-macrosphelides A and B were accomplished in this study. The key feature of our synthetic route involved the direct three-carbon homologation of the readily available Weinreb amide 6 by the addition of a trans-vinylogous ester anion equivalent and facile construction of the 16-membered macrolide skeleton of macrosphelides via an intramolecular nitrile oxide-olefin...

Journal: :international journal of health policy and management 0
reuben olugbenga ayeleke health systems section, school of population health, university of auckland, auckland, new zealand nicola north health systems section, school of population health, university of auckland, auckland, new zealand katharine ann wallis department of general practice and primary health care, school of population health, university of auckland, auckland, new zealand zhanming liang department of public health, school of psychology and public health, la trobe university, melbourne, australia annette dunham health systems section, school of population health, university of auckland, auckland, new zealand

background the need for competence training and development in health management and leadership workforces has been emphasised. however, evidence of the outcomes and impact of such training and development has not been systematically assessed. the aim of this review is to synthesise the available evidence of the outcomes and impact of training and development in relation to the competence of he...

2014
Dennis Imbri Johannes Tauber Till Opatz

The present review discusses the known synthetic routes to the lamellarin alkaloids published until 2014. It begins with syntheses of the structurally simpler type-II lamellarins and then focuses on the larger class of the 5,6-saturated and -unsaturated type-I lamellarins. The syntheses are grouped by the strategy employed for the assembly of the central pyrrole ring.

Journal: :iranian journal of catalysis 2013
somayeh ghasemi mojtaba baghernejad khodabakhsh niknam

sulfuric acid {[3-(3-silicapropyl)sulfanyl]propyl}ester (saspspe) is employed as a recyclable catalyst for the synthesis of α-amino nitriles. these syntheses were performed via a one-pot three-component condensation of aldehydes, amines, and trimethylsilyl cyanide under mild reaction conditions at room temperature. the catalyst could be recycled and reused several times without any loss of effi...

Abdol Hajipour Amin Zarei, Leila Khazdooz, Nafisehsadat Sheikhan

An efficient, mild and environmentally friendly method was developed for the Strecker reaction to synthesize α-aminonitriles in the presence of methyl imidazolium hydrogen sulfate ([Hmim][HSO4]) as an efficient catalyst. These syntheses were performed via a one-pot three-component condensation of aldehydes (or ketones), amines, and trimethylsilyl cyanide under mild and solvent free c...

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