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Carbon‐13 NMR studies of the biologically active nor‐diterpenoid dilactones from Podocarpus plants
Author(s) -
Hayashi Yuji,
Matsumoto Takeshi,
Uemura Motokazu,
Koreeda Masato
Publication year - 1980
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270140203
Subject(s) - steric effects , chemistry , stereochemistry , terpenoid , chemical shift , two dimensional nuclear magnetic resonance spectroscopy , carbon 13 nmr
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.