New Epoxy-Substituted Nitrogenous Bisabolene-Type Sesquiterpenes from a Hainan Sponge Axinyssa sp.

Two new uncommon epoxy-substituted nitrogenous bisabolene-type sesquiterpenes, 3-formamido7,8-epoxy-alpha-bisabolane (4), 3-isocyano-7,8-epoxy-alpha-bisabolane (5), together with three known related sesquiterpenes, 1-3, were isolated from the Hainan sponge Axinyssa sp. Their structures were determined on the basis of extensive spectroscopic analyses and by comparison of their NMR data with those of structurally related compounds.