1,720,976 research outputs found
Reagent Controlled Diastereoselective Aminations with a New Chiral Nosyloxycarbamate
No full textThe synthesis of a new chiral nosyloxycarbamate derived from Helmchen's auxiliary is described. Reactions performed with this aminating reagent successfully give the formation of diastereomeric allylic carbamates or diastereomeric aziridines starting from different kinds of olefins
Direct amination of β-oxo esters
No full textThe reaction of NsONHCO(2)Et, in the presence of CaO, with beta -oxo esters gives the corresponding aminated products in yields up to 58%. A substrate carrying the Oppolzer sultam undergoes amination with 40% diastereoselectivity. (C) 2001 Elsevier Science Ltd. All rights reserved
Can functionalized N-acyloxy aziridines be easily deprotected?
No full textNitrogen deprotection of polyfunctionalized N-acyloxy aziridines was studied considering the compatibility of reaction conditions with the different functional groups on the aziridine ring. (c) 2005 Academie des sciences. Published by Elsevier SAS. All rights reserved
Functionalised Enones as Starting Materials for the Construction of Aziridine Scaffolds
No full textalpha-Substituted beta-keto esters have been transformed by means of a straightforward procedure into aziridine-1,2-dicarboxylates, which have been efficiently converted into alkenyl aziridine-1,2-dicarboxylates through Wittig olefination reaction. The possibility of aziridine ring elaborations and the presence of an olefin function make these new molecules suitable scaffolds for further derivatisation into potential bioactive targets
Sintesi di un Nuovo Carbammato Chirale e Suo Impiego come Agente Amminante Diastereoselettivo
No full textDiastereoselective aziridination of chiral alpha-carbonyl enoates
No full textNosyloxycarbamates very efficiently aziridinate optically active a-carbonyl enoates with high levels of diastereoselectivity under mild conditions and in a straightforward process
Derivati Malonici Contenenti Residui Ammino Acidici come Scaffold nella Sintesi di Peptidomimetici
No full textComunicazione orale ORG-O-1
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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