反应详情

To a solution of N,O-dimethylhydroxylamine hydrochloride (2.63 g, 27 mmol) and iPr2NEt (4.70 mL, 27 mmol) in CH2Cl2 (30 mL) was added AlMe3 (1.8 M solution in toluene, 15 mL, 27 mmol) dropwise at 0° C. under Ar atmosphere. After stirring for 1 h, a solution of methyl 5-methoxy-4-oxo-1-[3-(trifluoromethyl)phenyl]-1,4-dihydropyridazine-3-carboxylate (2.95 g, 9 mmol) in CH2Cl2 (30 mL) was added dropwise, and the mixture was stirred for 1 h at 0° C. The reaction mixture was poured into ice-water and extracted with AcOEt. The extract was washed with brine, dried over MgSO4, and concentrated under reduced pressure. The residue was purified by basic silica gel column chromatography eluting with AcOEt and recrystallized from hexane/AcOEt to give the title compound (2.15 g, 67% yield) as off-white crystals: mp 170-171° C.; 1H NMR (300 MHz, CDCl3): δ ppm 3.41 (3H, s), 3.71 (3H, s), 3.98 (3H, s), 7.63-7.71 (2H, m), 7.80-7.86 (1H, m), 7.88 (1H, s), 7.98 (1H, s). Anal. Calcd for C15H14F3N3O4: C, 50.42; H, 3.95; N, 11.76. Found: C, 50.48; H, 4.07; N, 11.66.

1. stirringthe mixture was stirred for 1 h at 0° C
2. extractionextracted with AcOEt
3. washThe extract was washed with brine
4. dry with materialdried over MgSO4
5. concentrationconcentrated under reduced pressure
6. customThe residue was purified by basic silica gel column chromatography
7. washeluting with AcOEt
8. customrecrystallized from hexane/AcOEt