Co-occurrence of two terpenoid isocyanide-formamide pairs in a marine sponge (Halichondria sp.)

From a marine sponge (Halichondria sp.) we have isolated amorphane sesquiterpenoids that are substituted at C-10 by isocyanide (1), formamide (2), and isothiocyanate (3), and diterpenoids that are 3,7,11,15- tetramethyl-1,6,10,14-hexadecatetraenes (geranyllinaloyl) bearing isocyanide (13), formamide (14), and isothiocyanate (16) functions at C-3.