Carbon-13 NMR studies of the biologically active nor-diterpenoid dilactones from Podocarpus plants
✍ Scribed by Yuji Hayashi; Takeshi Matsumoto; Motokazu Uemura; Masato Koreeda
- Publisher
- John Wiley and Sons
- Year
- 1980
- Tongue
- English
- Weight
- 515 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0749-1581
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✦ Synopsis
Abstract
Carbon‐13 NMR signals of the biologically active norditerpenoid dilactones from Podocarpus plants were fully assigned by using selective ^1^H decoupling, coupling constants (^2^J~CH~), spin‐lattice relaxation times (T~1~) and correlation of the spectra of more than thirty dilactone congeners. The spectra of five nagilactones, B, C, D, E and F, which constitute representative members of three major structural types of the dilactones: (A) 8:14, 9:11‐dienolide (α‐pyrone) type, (B) 7α:8α‐epoxy‐9:11‐enolide type, and (C) 7:8,9:11‐dienolide type, were extensively analysed. Some characteristic steric interactions for the substituents on the ring system can be demonstrated from the spectral properties.