A New Epoxy-cadinane Sesquiterpene from the Marine Brown Alga Dictyopteris divaricata

A new epoxy-cadinane sesquiterpene, 4 beta, 5 beta-epoxycadinan-1 beta-ol (1), and six known cadinane sesquiterpenes: cadinan-1,4,5-triol (2), 4 alpha,5 beta-dihydroxycubenol (3), cubenol (4), cadinan-3-ene-1,5-diol (5), cubenol-3-one (6), and torreyol (7), were isolated from a sample of marine brown alga Dictyopteris divaricata collected off the coast of Yantai (China). Their structures were established by detailed MS and NMR spectroscopic analysis, as well as comparison with literature data.