AIDS-072921 AIDS072921 Leptomycin derivative Methyl (2E,10E,12E,16Z,18E)-17-ethyl-6-hydroxy-9-(hydroxymethyl)-3,5,7,11,15-pentamethyl-19-(3-methyl-6-oxo-3,6-dihydro-2H-pyran-2-yl)-8-oxononadeca-2,10,12,16,18-pentaenoate