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NMR and conformational studies of the cyclobutane ring involved in the bicyclo [4.2.0]octane system of a tetracyclic diterpene structure
Author(s) -
Manh Duc Do Khac,
Fetizon Marcel,
Prévost Chantal,
Roy Pierre
Publication year - 1991
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260290903
Subject(s) - chemistry , cyclobutane , octane , bicyclic molecule , dihedral angle , diterpene , ring (chemistry) , coupling constant , stereochemistry , vicinal , computational chemistry , molecule , organic chemistry , hydrogen bond , physics , particle physics
Conformational studies were performed on the bicyclo [4.2.0] octane system of a series of related tetracyclic diterpenes, using molecular mechanics and 1 H NMR. Both methods gave compatible results, but did not permit the deduction of any quantitative relationship linking the vicinal coupling constants to the cyclobutane dihedral angles. Nevertheless, the Karplus relationship allowed a qualitative interpretation of the coupling constants in terms of conformation. A set of characteristic 1 H NMR coupling constants was obtained which allows the interpretation of the 1 H NMR spectrum of any compound presenting a similar system.