New Triterpene-Ketides (Merotriterpenes), Haliclotriol A and B, from an Indo–Pacific Haliclona Sponge

Two new terpene-ketides, haliclotriol A and B (1 and 3), have been isolated from the Indonesian sponge Haliclona sp. Their structure and relative stereochemical features were determined by 1D and 2D NMR spectroscopy and by converting 1 to its corresponding triacetate 2. The hexacyclic core of 1 and 3 appears to arise via a biosynthetic cyclization of a hexaprenylbenzoquinone type precursor and 1 has an additional C2 functionalization on the aromatic ring. Haliclotriol B demonstrated weak antimicrobial activity against B. subtilis and S. aureus.