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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

✍ Scribed by Duc Do Khac Manh; Marcel Fetizon; Chantal Prévost; Pierre Roy

Publisher: John Wiley and Sons
Year: 1991
Tongue: English
Weight: 528 KB
Volume: 29
Category: Article
ISSN: 0749-1581
DOI: 10.1002/mrc.1260290903

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✦ Synopsis

Abstract

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.

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