56257-59-1 Altertoxin II BRN 5156144 CCRIS 2191 Perylo(1,2-b)oxirene-7,11-dione, 7a,8a,8b,8c,9,10-hexahydro-1,6,8c-trihydroxy-, (7aR,8aR,8bS,8cR)-