Theoretical and experimental NMR study of protopine hydrochloride isomers.

Jaromír Tousek, Katerina Malináková, Jirí Dostál, Radek Marek

Index: Magn. Reson. Chem. 43(7) , 578-81, (2005)

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Abstract

The 1H and 13C 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 approximately 68%.Copyright 2005 John Wiley & Sons, Ltd