Synthesis, NMR data and theoretical study of semi-synthetic derivatives from trans-dehydrocrotonin
Abstract
In this work, the 19-nor-diterpenoid clerodane-type dehydrocrotonin (t-DCTN) was a primary source for a two-step synthetic procedure. The catalytic hydrogenation of t-DCTN afforded the semi-synthetic trans-crotonin (t-CTN) in a highly stereospecific reaction confirmed by DFT calculations. The unsaturated carbonyl group of t-DCTN was reduced by NaBH4/EtOH providing an epimeric α-OH and β-OH mixture named t-CTN-OL. Both epimeric compound structures t-CTN-α-OL and t-CTN-β-OL were elucidated by 1D and 2D NMR spectral data. Comparison of NMR data from natural source of t-CTN was done to confirm the stereochemical authenticity of semi-synthetic t-CTN. Calculated NMR data for all described derivatives (semi-synthetic t-CTN and its t-CTN-OL epimeric mixture) were performed using B3LYP/6-311G++(d,p) level of theory which validated our previously developed NMR theoretical protocol for structural analyses of organic molecules. Topological data using Quantum Theory of Atoms in Molecules (QTAIM) of t-CTN quantified and qualified intramolecular interactions of its most stable conformer.
- Publication:
-
Journal of Molecular Structure
- Pub Date:
- March 2016
- DOI:
- 10.1016/j.molstruc.2015.12.045
- Bibcode:
- 2016JMoSt1108..533S
- Keywords:
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- t-DCTN;
- t-CTN;
- t-CTN-OL;
- NMR;
- QTAIM;
- DFT