(S)-12-hydroxygeranylgeraniol-derived diterpenes from the brown alga Bifurcaria bifurcata

Four novel diterpenes were isolated from the brown alga Bifurcaria difurcat a collected off the Atlantic coast from Morocco, and their structures estab lished by spectral and chemical methods. These compounds are acyclic diterp enes derived from (S)-12-hydroxygeranylgeraniol. One of them is its dehydra tion product at C-12. while the others are its oxidation derivatives : the methyl ester of the acid at C-l and two stereoisomers (Z and E) of the alde hyde at C-l. These results art: discussed from a chemotaxonomic point of vi ew. (C) 2001 Elsevier Science Ltd. All rights reserved.