Design, Synthesis, EPR-Studies and Conformational Bias of Novel Spin-Labeled DCC-Analogues for the Highly Regioselective Labeling of Aliphatic and Aromatic Carboxylic Acids.

Autor: Gölz JP; Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Str. 1, 53121, Bonn, Germany., NejatyJahromy Y; Institut für Physikalische und Theoretische Chemie, Universität Bonn, Wegelerstr. 12, 53115, Bonn, Germany., Bauer M; Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie, Universität Bonn, Beringstraße 4, 53115, Bonn, Germany., Muhammad A; Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Str. 1, 53121, Bonn, Germany., Schnakenburg G; Institut für Anorganische Chemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany., Grimme S; Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie, Universität Bonn, Beringstraße 4, 53115, Bonn, Germany., Schiemann O; Institut für Physikalische und Theoretische Chemie, Universität Bonn, Wegelerstr. 12, 53115, Bonn, Germany., Menche D; Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Str. 1, 53121, Bonn, Germany. dirk.menche@uni-bonn.de.
Jazyk: angličtina
Zdroj: Chemistry (Weinheim an der Bergstrasse, Germany) [Chemistry] 2016 Jul 04; Vol. 22 (28), pp. 9591-8. Date of Electronic Publication: 2016 Jun 07.
DOI: 10.1002/chem.201600528
Abstrakt: Novel types of spin-labeled N,N'-dicyclohexylcarbodiimides (DCC) are reported that bear a 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) residue on one side and different aromatic and aliphatic cyclohexyl analogues on the other side of the diimide core. These readily available novel reagents add efficiently to aliphatic and aromatic carboxylic acids, forming two possible spin-labeled amide derivatives with different radical distances of the resulting amide. The addition of aromatic DCC analogues proceeds with excellent selectivity, giving amides where the carboxylic acid is exclusively connected to the aromatic residue, while little or no selectivity was observed for the aliphatic congeners. The usefulness of these adducts in structural studies was demonstrated by EPR (electron paramagnetic resonance) measurements of biradical adducts of biphenyl-4,4'-dicarboxylic acids. These analyses also reveal high degrees of conformational bias for aromatic DCC derivatives, which further underlines the powerfulness of these novel reagents. This observation was further corroborated by quantum chemical calculations, giving a detailed understanding of the structural dynamics, while detailed information on the solid state structure of all novel reagents was obtained by X-ray structure analyses.
(© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
Databáze: MEDLINE
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