Identification of the eight-membered heterocycles hicksoanes A-C from the Gorgonian subergorgia hicksoni

Novel eight-membered heterocycles, named hicksoanes AC, were isolated from the gorgonian Subergorgia hicksoni. Their structures, including the absolute configuration of all three stereocenters, were determined by means of extensive spectroscopic data, Hicksoanes have a unique structure containing a triazocane cycle, which is substituted by isoleucine and tryptophan moieties. Hicksoanes A-C showed antifeeding activity against goldfish at natural concentration (10 mu gmL(-1)).