Antifungal peroxyketal acids from an Okinawan marine sponge of Plakortis sp.

Antifungal peroxyketal acids and their methyl esters, the peroxyplakoric acids A1 methyl ester (1), A2 methyl ester (2), A3 methyl ester (3), B1 methyl ester (4), and B3 methyl ester (5), were separated from an Okinawan marine sponge of Plakortis sp. The absolute stereostructures 1-5 have been elucidated on the basis of chemical and physicochemical evidence.