[Cl:1][C:2]1[C:7]([CH3:8])=[CH:6][CH:5]=[CH:4][N:3]=1.OO.NC(N)=[O:13].FC(F)(F)C(OC(=O)C(F)(F)F)=O.O>C(Cl)Cl>[Cl:1][C:2]1[C:7]([CH3:8])=[CH:6][CH:5]=[CH:4][N+:3]=1[O-:13]To a mixture of 2-chloro-3-methylpyridine (15 g, 118 mmol) and urea hydrogen peroxide (44.07 g, 468.5 mmol) in DCM (300 mL) was added trifluoroacetic anhydride (98.55 g, 469.2 mmol) dropwise at 0° C. The mixture was stirred at room temperature for 20 h. The mixture was then poured into water (150 mL), and the layers were separated. The organic layer was washed with saturated aqueous Na2S2O3 (20 mL), dried over Na2SO4, filtered, and the filtrate was concentrated under reduced pressure. The crude product was purified by silica gel flash chromatography (DCM:MeOH, 100:0 to 10:1) to afford the title compound (14.5 g, 86%) as a colorless solid.
Wird geladen…