Posaconazole Impurity A

1-(4-(((3R,5R)-5-((1H-1,2,4-triazol-1-yl)methyl)-5-(2,4-difluorophenyl)tetrahydrofuran-3-yl)methoxy)phenyl)-4-(4-(1-((2S,3S)-2-hydroxypentan-3-yl)-5-oxo-1H-1,2,4-triazol-4(5H)-yl)phenyl)piperazin-2-one