Hodgsonal, a new drimane sesquiterpene from the mantle of the Antarctic nudibranch Bathydoris hodgsoni

A new drimane sesquiterpene, hodgsonal (1), has been isolated from the mantle extract of the Antarctic opisthobranch mollusc Bathydoris hodgsoni. The structure of 1, including the absolute stereochemistry, has been elucidated by spectroscopic and chemical methods.The localization of 1 in the mantle and the analogies with related drimane compounds may indicate a defensive role against predators.