Loading…

Nucleophilic Reactivities of Primary and Secondary Amines in Acetonitrile

The kinetics of the reactions of primary and secondary amines with benzhydrylium ions and quinone methides in acetonitrile have been studied under pseudo‐first‐order conditions (high excess of amines) by UV/Vis spectrophotometry. Generally, the plots of kobs versus amine concentration were linear, i...

Full description

Saved in:
Bibliographic Details
Published in:European Journal of Organic Chemistry 2009-12, Vol.2009 (36), p.6379-6385
Main Authors: Kanzian, Tanja, Nigst, Tobias A., Maier, Andreas, Pichl, Stefan, Mayr, Herbert
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The kinetics of the reactions of primary and secondary amines with benzhydrylium ions and quinone methides in acetonitrile have been studied under pseudo‐first‐order conditions (high excess of amines) by UV/Vis spectrophotometry. Generally, the plots of kobs versus amine concentration were linear, in line with a second‐order rate law. However, for some reactions of secondary amines with quinone methides, the plots of kobs versus amine concentration showed an upward curvature, which indicates rate‐limiting deprotonation of the initially formed adduct by a second molecule of amine. From the second‐order rate constants k2 for the attack on the electrophiles by the amines, the nucleophilicity parameters N and s for the amines were determined from the linear free energy relationship log k2 (20 °C) = s(N + E). The rates of the reactions of the amines with benzhydrylium ions are strongly affected by solvent polarity, in sharp contrast to the analogous reactions of other neutral nucleophiles.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) The kinetics of the reactions of primary and secondary amines with benzhydrylium ions and quinone methides have been studied spectrophotometrically in acetonitrileat 20 °C. From the linear free energy relationship log k2 (20 °C) = s(N + E), the N and s parameters of these amines were determined.
ISSN:1434-193X
1099-0690
DOI:10.1002/ejoc.200900925