STRUCTURES AND CONFORMATIONS OF NEW NINE-MEMBERED RING DITERPENOIDS FROM THE MARINE ALGA DICTYOTA DICHOTOMA

Abstract
New nine-membered ring diterpenes acetyldictyolal (2), hydroxyacetyldictyolal (4) isodictyohemiacetal (5) and dictyodiacetal (7) have been isolated. Their structures and approximate conformations have been determined by spectral and chemical means.