Callitrin, callitrisin, dihydrocallitrisin, columellarin and dihydrocolumellarin, new sesquiterpene lactones from the heartwood of callitris columellaris.
✍ Scribed by Douglas J. Brecknell; Raymond M. Carman
- Book ID
- 104240311
- Publisher
- Elsevier Science
- Year
- 1978
- Tongue
- French
- Weight
- 206 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
Five new sesquiterpene lactones (1,2,4,5 and 6) have been isolated from the hexane extract of the heartwood of CalZitris colwneZZaris, F. Muell. (syn. C. gtica). In addition, a sixth lactone (3), previously reported' as a synthetic compound, has been established as a natural product from the same source. Callitrin (l), callitrisin (2) and the germacranolide (3) were extracted into aqueous silver nitrate solution* from the neutral hexane fraction. Treatment of the silver nitrate solution with excess asnnonia liberated an oil from which the crystalline lactones (l), (2) and (3) were isolated by chromatography over alumina containing ca 10% silver nitrate. Dihydrocallitrisin (4) and the guaianolides dihydrocolumellarin (5) and columellarin (6) were isolated by chromatography of the silver nitrate insoluble portion of the extract using "Merck" prepacked silica gel columns. Callitrin (l), C15H2202, m.p. 82-83", [ulD +225', showed a y-lactone group (1780 cm-') and two double bonds (1645, 1618, 1005, 907, 890 cm-', five vinylic n.m.r. protons), a quaternary methyl group (5 1.02), a methyl on a double bond (6 1.69) and a doublet methyl (6 1.15). An elemene-type skeleton was indicated, and a six-line one-proton system at 6 4.47