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Carbon‐13 NMR study of (20,24)‐epoxydammarane triterpenes
Author(s) -
Francisco Cosme G.,
Freire Raimundo,
Hernández Rosendo,
Salazar José A.,
Suárez Ernesto,
Cortés Manuel
Publication year - 1984
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.1270220108
Subject(s) - dammarane , terpene , chemistry , epimer , stereochemistry , tetrahydrofuran , triterpene , carbon 13 nmr , organic chemistry , solvent , alternative medicine , pathology , medicine
Assignments of the 13 C NMR signals of the dammarane triterpenes, 3β,25,30‐trihydroxy‐(20 R ,24 R )‐epoxydammaran‐16‐one 3,30‐diacetate (trevoagenin A diacetate) (2), its 20 S ‐isomer (trevoagenin B diacetate) (3) and their related (20 R )‐3β,30‐diacetoxy‐16‐oxo‐25,26,27‐trisnordammarane‐24,20‐lactone (4) and its 20 S ‐isomer (5) have been achieved. Suitable tetrahydrofuran models have been synthesized in order to aid the 13 C NMR assignments of the side‐chain carbons of the above‐mentioned compounds. The remarkable chemical shift differences observed for C‐21 and C‐22 between each pair of the C‐20 epimers (2, 3 and 4, 5) allowed the confirmation of the C‐20 stereochemistry of these ocotillol‐type dammarane triterpenes.