Tricyclic Diterpenes Research Articles

THE REVISED STRUCTURE OF DISPERMOL AND TOTAL SYNTHESIS OF (−)-DISPERMONE, (+)-DISPERMOL, AND (+)-MAYTENOQUINONE

Abstract The total syntheses of natural tricyclic diterpenes, (−)-dispermone (1), (+)-dispermol (5), and (+)-maytenoquinone (3), were successfully achieved starting from (R)-(−)-α-cyclocitral (6) and the proposed structure (2) for dispermol was revised to 12-hydroxy-13-methoxytotara-8,11,13-triene (5).

SYNTHESIS OF (±)-MAYTENOQUINONE, (±)-DISPERMOL, AND (±)-DISPERMONE

Abstract Three tricyclic diterpenes, maytenoquinone (1), dispermol (2), and dispermone (3), were synthesized as racemic forms starting from β-cyclocitral (5) by a simple route. Condensation of (5) with 3,4-dimethoxy-2-isopropylbenzyl chloride (8) afforded an alcohol (9) which was successively subjected to oxidation, intramolecular cyclization, demethylation, and oxidation to give (±)-1. Reductive cleavage of a hydroxyl group in (9) followed by cyclization gave (±)-2 which was further converted into (±)-3.

Diterpenoids. XV. Conformational Studies. III. Temperature Dependent Proton Magnetic Resonance Spectra of Ring C Aromatic Tricyclic Diterpene

Temperature dependent proton magnetic resonance studies of four basic ring C aromatic tricyclic diterpenes (I, II, III and IV) are discussed and shown to be able to characterize each stereoisomers. This method is also applied to the analysis of 7-oxo and 20-nor derivatives.

Isolation of geranyl geraniol from the unsaponifiable fraction of linseed oil

From the unsaponifiable fraction (63 g) of linseed oil (25 kg), two terpenic alcohols were isolated by alumina column, thin-layer, and gas-liquid chromatography. They were identified as phytol and geranyl geraniol (a precursor of bi- and tricyclic diterpenes) by infrared and nuclear magnetic resonance spectroscopy, ozonolysis, and mass spectrometry.