gambierol analogues have been prepared from an advanced intermediate of our totalsynthesis of gambierol and investigated for their toxicity against mice, thus providing the first systematic structure-activity relationships (SAR) of this polycyclic ether class of marine toxin. The SAR studies described herein clearly indicate that 1) the C28=C29 double bond within the H ring and the unsaturated side chain
toxin, isolated as a toxic constituent from the marine dinoflagellate Gambierdiscus toxicus. We describe here the synthesis and biologicalevaluation of structural analogues of gambierol. The present preliminary structure-activity relationship studies clearly indicate that the H ring functionality and the unsaturated sidechain of gambierol are crucial for its potenttoxicity.
The axial C6OH group in gambierolisolatedfrom the dinoflagellate, Gambierdiscustoxicus, was inverted to equatorial disposition and esterified with (S)- and (R)-MTPA. NMR analysis of these esters established S configuration at C6, thus allowing determination of the absolute configuration of the whole molecule.