The crystal and molecular structure of the pseudoguaianolide autumnolide

Robert B. Von Dreele, George Pettit, Gordon M. Cragg, Richard H. Ode

Research output: Contribution to journalArticle

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Abstract

A crystal structure analysis of the pseudoguaianolide autumnolide (3) has revealed a conformation of the seven-membered ring that is markedly different from that found for the very similar bromohelenalin. The principal difference between the two conformations involves a drastic twist of 111.0° about C6-C7 and associated rotations about all contiguous bonds. As a consequence of this molecular conformation, there is an unusual QH-pπ interaction in autumnolide which is not found in the other pseudoguaianoiides. The structure was solved by direct methods analysis of data from a crystal with space group P21 and a = 7.595 ± 0.004, b = 13.380 ± 0.009, c = 6.870 ± 0.006 Å, β = 92.87 ± 0.06°, Z = 2, and density ρcaled = 1.336 g/cm3. An anisotropic full-matrix least-squares refinement converged to a conventional residual of R = 0.058 for 2086 reflections recorded with Mo Kα radiation on an automatic four-circle diffractometer.

Original languageEnglish (US)
Pages (from-to)5256-5259
Number of pages4
JournalJournal of the American Chemical Society
Volume97
Issue number18
StatePublished - 1975

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Molecular Conformation
Molecular Structure
Least-Squares Analysis
Molecular structure
Conformations
Crystal structure
Radiation
Diffractometers
Crystals

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

The crystal and molecular structure of the pseudoguaianolide autumnolide. / Von Dreele, Robert B.; Pettit, George; Cragg, Gordon M.; Ode, Richard H.

In: Journal of the American Chemical Society, Vol. 97, No. 18, 1975, p. 5256-5259.

Research output: Contribution to journalArticle

Von Dreele, Robert B. ; Pettit, George ; Cragg, Gordon M. ; Ode, Richard H. / The crystal and molecular structure of the pseudoguaianolide autumnolide. In: Journal of the American Chemical Society. 1975 ; Vol. 97, No. 18. pp. 5256-5259.
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