Premium
J ‐Based Analysis and DFT–NMR Assignments of Natural Complex Molecules: Application to 3β,7‐Dihydroxy‐5,6‐epoxycholestanes
Author(s) -
Poza Jesús Javier,
Jiménez Carlos,
Rodríguez Jaime
Publication year - 2008
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200800358
Subject(s) - chemistry , chemical shift , molecule , coupling constant , carbon 13 nmr , epoxy , computational chemistry , stereochemistry , basis set , two dimensional nuclear magnetic resonance spectroscopy , organic chemistry , physics , particle physics
In order to reproduce the stereochemical dispositions of the epoxy and hydroxy functionalities, four 3β,7‐hydroxy‐5,6‐epoxycholestanes were easily prepared from cholesterol, and their NMR spectroscopic data were experimentally obtained from 1D and 2D NMR experiments. An exhaustive QM‐ J ‐based analysis was then performed to replicate the experimental H–H and C–H coupling constants as well as the 13 C NMR chemical shifts. The B3LYP GIAO methodology with the 6‐311‐G(d,p) basis set was chosen and showed that the data obtained from rings A and B were sufficient to calculate the correct stereochemistry of the 5,6‐epoxy and 7‐hydroxy groups. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)