14779-52-3Relevant articles and documents
Stereodinamics of N-Ethyl-N-methyl-2-aminobutane
Danehey, Charles T.,Grady, Gilbert L.,Bonneau, Philippe R.,Bushweller, C. Hackett
, p. 7269 - 7279 (2007/10/02)
N-Ethyl-N-methyl-2-aminobutane (EMAB) is the simplest acyclic trialkylamine which possesses a chiral carbon bonded to a chiral nitrogen.The chiral carbon is configurationally stable, while the chiral nitrogen is configurationally labile via nitrogen inversion.The 1H dynamic NMR (DNMR) spectra of three selectively deuteriated derivatives of EMAB show a decoalescence into four subspectra with relative populations of 49percent, 22percent, 17percent, and 12percent at 104 K.The DNMR behavior can be simulated in terms of a model which involves a relatively high barrier for interconversion between diastereomers via nitrogen inversion (ΔG=7.3 kcal/mol) and lower barriers for conformational interconversion via isolated rotation (ΔG=6.4 and 5.6 kcal/mol).By using the NMR data and complementary molecular mechanics calculations, the 49percent and 12percent subspectra are assigned to conformations of the RCRN and SCSN stereoisomers, while the 22percent and 17percent subspectra are assigned to the RCSN and SCRN stereoisomers.Preferred conformations have the N-ethyl methyl group in one of the two positions gauche to the nitrogen lone pair, the Cl methyl of the 2-butyl group anti to the lone pair, and the C4 methyl of the 2-butyl group syn periplanar to the lone pair.There is no experimental evidence for conformations which have the methine proton or the N-ethyl methyl group anti to the lone pair.
