Conformation analysis of three germacranolides by the PM3 semi-empirical method
Konformaciona analiza tri germakranolida PM3 semi-empirijskom metodom
Abstract
The conformations of the C-6 lactonized germacranolides 1–3 were calculated by applying the PM3 semi-empirical method. The low-temperature 1H-NMR spectra of parthenolide (1) were also measured. The relations between the calculated and the experimentally determined geometries were established using a modified Karplus equation. The applied quantum-chemical calculations proved to be an efficient and easy-to-use tool for the elucidation and prediction of the properties of germacranolide-type sesquiterpene lactones.
Konformacije germakranolida 1–3, laktonizovanih u položaju (6), izračunate su primenom PM3 semi-empirijske MO metode. Takođe su snimljeni protonski NMR spektri partenolida (1) na niskim temperaturama. Pomoću modifikovane Karplusove jednačine je uspostavljena korelacija između eksperimentalno utvrđenih i izračunatih najstabilnijih konformacija. Zaključeno je da primenjena kvantno-hemijska izračunavanja brzo i pouzdano mogu predvideti i objasniti osobine seskviterpenskih laktona tipa germakranolida.
Keywords:
germacranolides / parthenolide / ridentin / 1β,10α-epoxy-3β,9β-diacetoxy-11α,13-dihydrocostunolide / conformations / PM3 semi-empirical calculationsSource:
Journal of the Serbian Chemical Society, 2003, 68, 4-5, 281-289Publisher:
- Serbian Chemical Society
DOI: 10.2298/JSC0305281M
ISSN: 0352-5139