Premium
Theoretical and experimental NMR study of protopine hydrochloride isomers
Author(s) -
Toušek Jaromír,
Maliňáková Kateřina,
Dostál Jiří,
Marek Radek
Publication year - 2005
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.1596
Subject(s) - chemistry , chemical shift , computational chemistry , cis–trans isomerism , quantum chemical , hydrochloride , molecule , stereochemistry , organic chemistry
The 1 H and 13 C NMR chemical shifts of cis ‐ and trans ‐protopinium salts were measured and calculated. The calculations of the chemical shifts consisted of conformational analysis, geometry optimization (RHF/6–31G** method) and shielding constants calculations (B3LYP/6–31G** method). Based on the results of the quantum chemical calculations, two sets of experimental chemical shifts were assigned to the particular isomers. According to the experimental results, the trans ‐isomer is more stable and its population is ∼68%. Copyright © 2005 John Wiley & Sons, Ltd.