Voriconazole Impurity 12; ent-Voriconazole; Voriconazole enantiomer; Voriconazole Imp. D (EP); Voriconazole Related Compound B (USP); Voriconazole EP Impurity D; Voriconazole USP Related Compound B; (alphaS,betaR)-alpha-(2,4-Difluorophenyl)-5-fluoro-beta-methyl-alpha-(1H-1,2,4-triazol-1-ylmethyl)-4-pyrimidineethanol