(2S,3′S,3a'R,5′R,7a'R)-5′-[(E)-5-(Furan-3-yl)-2-methylpent-1-en-1-yl]-3-hydroxy-3′,4,7′-trimethyl-1′,2′,3′,3a',5′,7a'-hexahydro-5H-spiro[furan-2,4′-inden]-5-one

The title compound, ircinianin, C25H32O4, belongs to the sesterterpene tetronic acid compound family and was isolated from the marine sponge Ircinia wistarii. These chemical scaffolds are pharmacologically relevant, since they represent a new class of glycine receptor modulators. The furan ring makes a dihedral angle of 35.14 (12)° to the 4-hydroxy-3-methylfuran-2(5H)-one ring. The crystal packing is characterized by intermolecular O—H...O hydrogen bonds, which generate [010] chains.