Showing structure for (11z)-21,28-dihydroxy-7-methoxy-5-methyl-19,26-dioxo-3-oxa-16-azaheptacyclo[15.12.0.0²,⁴.0²,⁸.0⁴,¹⁵.0¹⁸,²⁷.0²⁰,²⁵]nonacosa-1(29),6,11,17,20,22,24,27-octaen-9,13-diyne-6-carboxylic acid