Conformational analysis of (+)-germacrene A by variable-temperature NMR and NOE spectroscopy

Juan A. Faraldos; Shuiqin Wu; Joe Chappell; Robert M. Coates

doi:10.1016/j.tet.2007.04.037

Conformational analysis of (+)-germacrene A by variable-temperature NMR and NOE spectroscopy

Juan A. Faraldos, Shuiqin Wu, Joe Chappell, Robert M. Coates

Research output: Contribution to journal › Article › peer-review

74 Scopus citations

Abstract

(+)-Germacrene A, an important intermediate in sesquiterpene biosynthesis, was isolated in pure form from a genetically engineered yeast and was characterized by chromatographic properties (TLC, GC), MS, optical rotation, UV, IR, ¹H NMR, and ¹³C NMR data. Variable-temperature 500 MHz ¹H NMR spectra in CDCl₃ showed that this flexible cyclodecadiene ring exists as three NMR-distinguishable conformational isomers in a ratio of about 5:3:2 at or below ordinary probe temperature (25 °C). The conformer structures were assigned by ¹H NMR data comparisons, NOE experiments, and vicinal couplings as follows: 1a (52%, UU), 1b (29% UD), and 1c (19%, DU).

Original language	English
Pages (from-to)	7733-7742
Number of pages	10
Journal	Tetrahedron
Volume	63
Issue number	32
DOIs	https://doi.org/10.1016/j.tet.2007.04.037
State	Published - Aug 6 2007

Bibliographical note

Funding Information:
We are very grateful to Dr. A. M. Adio for exchanges of information and for 1D and 2D NMR spectra of an impure sample of germacrene A isolated from S. Canadensis, 26 Dr. Vera Mainz of the School of Chemical Sciences NMR Facility at the UI for assistance with the VT and NOE NMR experiments, and Dr. Jerome Baudry in the School of Chemical Sciences' Computer Applications Facility at the UI for consultations and advice concerning the MM2 calculations. This work was supported by grants from the National Institutes of Health (GM 13956 to RMC and GM 054029 to JC), and from the Kentucky Agriculture Experiment Station (JC).

Funding

We are very grateful to Dr. A. M. Adio for exchanges of information and for 1D and 2D NMR spectra of an impure sample of germacrene A isolated from S. Canadensis, 26 Dr. Vera Mainz of the School of Chemical Sciences NMR Facility at the UI for assistance with the VT and NOE NMR experiments, and Dr. Jerome Baudry in the School of Chemical Sciences' Computer Applications Facility at the UI for consultations and advice concerning the MM2 calculations. This work was supported by grants from the National Institutes of Health (GM 13956 to RMC and GM 054029 to JC), and from the Kentucky Agriculture Experiment Station (JC).

Funders	Funder number
RMC Research Corporation	GM 054029
National Institutes of Health (NIH)	GM 13956
Kentucky Agricultural Experiment Station

ASJC Scopus subject areas

Biochemistry
Drug Discovery
Organic Chemistry

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title = "Conformational analysis of (+)-germacrene A by variable-temperature NMR and NOE spectroscopy",

abstract = "(+)-Germacrene A, an important intermediate in sesquiterpene biosynthesis, was isolated in pure form from a genetically engineered yeast and was characterized by chromatographic properties (TLC, GC), MS, optical rotation, UV, IR, 1H NMR, and 13C NMR data. Variable-temperature 500 MHz 1H NMR spectra in CDCl3 showed that this flexible cyclodecadiene ring exists as three NMR-distinguishable conformational isomers in a ratio of about 5:3:2 at or below ordinary probe temperature (25 °C). The conformer structures were assigned by 1H NMR data comparisons, NOE experiments, and vicinal couplings as follows: 1a (52%, UU), 1b (29% UD), and 1c (19%, DU).",

author = "Faraldos, {Juan A.} and Shuiqin Wu and Joe Chappell and Coates, {Robert M.}",

note = "Funding Information: We are very grateful to Dr. A. M. Adio for exchanges of information and for 1D and 2D NMR spectra of an impure sample of germacrene A isolated from S. Canadensis, 26 Dr. Vera Mainz of the School of Chemical Sciences NMR Facility at the UI for assistance with the VT and NOE NMR experiments, and Dr. Jerome Baudry in the School of Chemical Sciences' Computer Applications Facility at the UI for consultations and advice concerning the MM2 calculations. This work was supported by grants from the National Institutes of Health (GM 13956 to RMC and GM 054029 to JC), and from the Kentucky Agriculture Experiment Station (JC).",

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AU - Coates, Robert M.

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Conformational analysis of (+)-germacrene A by variable-temperature NMR and NOE spectroscopy

Abstract

Bibliographical note

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ASJC Scopus subject areas

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