(2E,4E,6E,12E)-16,20-dihydroxy-21-methoxy-3-methyl-10-phenyl-9-azabicyclo[17.3.0]docosa-2,4,6,12,19-pentaene-8,18-dione 生成 [(2E,4E,6E,12E)-16-ethoxycarbonyloxy-21-methoxy-3-methyl-8,18-dioxo-10-phenyl-9-azabicyclo[17.3.0]docosa-2,4,6,12,19-pentaen-20-yl] ethyl carbonate