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Complexation of hydroxylated ent ‐kaurane diterpenoids with boric acid as an aid to the assignment of the 13 C NMR spectra
Author(s) -
FernándezGadea Francisco,
Jimeno María L.,
Rodríguez Benjamín
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.1270220809
Subject(s) - boric acid , chemistry , chemical shift , nmr spectra database , spectral line , carbon 13 nmr , stereochemistry , organic chemistry , physics , astronomy
The 13 C NMR spectra of some hydroxylated ent ‐kaurane diterpenoids were measured in CDCl 3 ‐Py‐d 5 (1:1) solution and also after addition of boric acid. Complexation of ent ‐3β,18‐, ent ‐7α,15β‐, ent ‐7α,15α‐, ent ‐15β,16β‐ and ent ‐16β,17‐dihydroxy derivatives with boric acid produced considerable chemical shift changes and marked broadening of the signals of the hydroxy‐bearing and neighbouring carbon atoms. This behaviour provides a useful and reliable method for assigning the 13 C NMR spectra of these compounds.