(13α,17aα)-1α,14β:21,23-Diepoxy-6-hydroxy-4,4-dimethyl-3,16-dioxo-D-homo-24-nor-17-oxa-6,7-seco-5α-chola-7,20,22-triene-6-carboxylic acid methyl ester [ 22255-07-8 ]