(2R,3R,4R,5S,6S)-2-(acetoxymethyl)-6-(5-(4-((E)-3,3-dimethyl-4-((2-methyl-1-(4-methylpiperazin-1-yl)-1-oxopropan-2-yl)amino)-4-oxobut-1-en-1-yl)benzyl)-4-isopropyl-2-methoxyphenyl)tetrahydro-2H-pyran-3,4,5-triyl triacetate