RUBROSKYRIN

(8S,17aR,19R)-7,8,8aα,9-Tetrahydro-1,4,6,8α,10,15,19-heptahydroxy-2,12-dimethyl-9α,17α-methanonaphtho[2',3':5,6]cyclohept[1,2-d]anthracene-5,11,14,16,18(17H)-pentone