Snyderol derivatives from Laurencia obtusa collected in Corsica

Abstract 8-keto-10-dehydrobromo-γ-snyderol ( 1 ), a new sesquiterpene exhibiting the unusual γ-snyderane skeleton, was isolated from the ethyl acetate extract of Laurencia obtusa collected in Ajaccio (Corsica, France). ( 1 ) was isolated and fully characterized by detailed spectroscopic analysis. Six known compounds were identified after column chromatography steps using a 13 C NMR based computerized method developed in our laboratory: α-snyderol ( 2 ), two rearranged derivatives of α-snyderol ( 3 , 4 ), 8-keto-10-dehydrobromo-β-snyderol ( 5 ), β-snyderol ( 6 ) and 8-hydroxy-β-snyderol ( 7 ).