Premium
Chiral discrimination of aliphatic amines and amino alcohols using NMR spectroscopy
Author(s) -
Wenzel Thomas J.,
Rollo Ryan D.,
Clark Rebecca L.
Publication year - 2012
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.2855
Subject(s) - chemistry , resorcinarene , enantiomer , amide , enantiomeric excess , derivatization , nuclear magnetic resonance spectroscopy , organic chemistry , crown ether , ether , chiral derivatizing agent , medicinal chemistry , enantioselective synthesis , high performance liquid chromatography , chiral column chromatography , catalysis , molecule , ion
Two methods are compared for analyzing the enantiomeric purity of aliphatic amines and amino alcohols using NMR spectroscopy. The first employs (+)‐(18‐crown‐6)‐2,3,11,12‐tetracarboxylic acid as a chiral NMR solvating agent in methanol‐ d 4 . The second involves a derivatization scheme in which the amine is reacted with naphtho[2,3‐ c ]furan‐1,3‐dione to form the corresponding amide. The naphthyl amide is then mixed with a chiral calix[4]resorcinarene in deuterium oxide. The crown ether only produces sufficient enantiomeric discrimination to determine enantiomeric purity for three of the nine substrates studied. The system with the naphthyl amide and a calix[4]resorcinarene produces enantiomeric discrimination of sufficient magnitude to determine enantiomeric purity for all nine substrates. The H1 and H4 resonances of the naphthyl ring are especially suitable to monitor for enantiomeric discrimination. The order of the ( R )‐ and ( S )‐enantiomers of the H1 and H4 resonances exhibit specific trends for aliphatic amines and amino alcohols that correlate with the absolute configuration. Copyright © 2012 John Wiley & Sons, Ltd.