Cabazitaxel Impurity: 1S,2S,3R,4S,7R,9S,10S,12R,15S)-4-(Acetyloxy)-15-{[(2R,3S)-3-amino-2-hydroxy-3-phenylpropanoyl]oxy}-1-hydroxy-9,12-dimethoxy-10,14,17,17-tetramethyl-11-oxo-6-oxatetracyclo[11.3.1.03,10.04,7]heptadec-13-ene-2-yl benzoate(Cabazitax.