(13S,15S)-2alpha,12alpha-diacetoxy-6-hydroxy-13,16-cycloabieta-5,8-dien-7,11,14-trione (2alpha,12alpha,13beta)-6-hydroxy-7,11,14-trioxo-13,17-cycloabieta-5,8-diene-2,12-diyl diacetate InChI=1/C24H28O8/c1-10-7-24(10)20(30)14-15(17(28)21(24)32-12(3)26)23(6)9-13(31-11(2)25)8-22(4,5)19(23)18(29)16(14)27/h10,13,21,29H,7-9H2,1-6H3/t10?,13-,21-,23+,24+/m0/s Xanthanthusin I spiro[cyclopropane-1,2'(1'H)-phenanthrene]-1',4',10'(3'H,6'H)-trione, 3',6'-bis(acetyloxy)-4'b,5',7',8'-tetrahydro-9'-hydroxy-2,4'b,8',8'-tetramethyl-, (1S,3'R,4b'S,6'S)-