methyl (1R,13S,15R,17S)-13-[(3aR,4R,5aR,5S,10bR,3a1R)-4-acetoxy-3a-ethyl-6-formyl-5-hydroxy-8-methoxy-5-(methoxycarbonyl)-3a,3a1,4,5,5a,6,11,12-octahydro-1H-indolizino[8,1-cd]carbazol-9-yl]-17-ethyl-17-hydroxy-1,11-diazatetracyclo[13.3.1.04,12.05,10]nonadeca-4(12),5(6),7,9-tetraene-13-carboxylate sulfuric acid