Showing structure for methyl 7,14-dihydroxy-18,18-dimethyl-5,12-dioxo-9-(prop-1-en-2-yl)-2,17-dioxapentacyclo[11.8.0.0³,¹¹.0⁴,⁸.0¹⁶,²¹]henicosa-1(21),3,8,10,13,15,19-heptaene-7-carboxylate