58775-51-2 5H-Furo(3',2':4,5)furo(3,2-b)xanthen-5-one, 3a,12a-dihydro-3a,6-dihydroxy-4-methoxy-, (3aR,12aR)- 5H-Furo(3',2':4,5)furo(3,2-b)xanthen-5-one, 3a,12a-dihydro-3a,6-dihydroxy-4-methoxy-, (3aR-cis)- Austocystin I