N,5-Dimethoxy-N-methyl-4-oxo-1-[3-(trifluoromethyl)phenyl]-1,4-dihydropyridazine-3-carboxamide → 3-Acetyl-5-methoxy-1-[3-(trifluoromethyl)phenyl]pyridazin-4(1H)-one

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Reaction Steps

MeMgBr (3 M solution in diethyl ether, 4 mL, 12 mmol) was added dropwise at −78° C. to a solution of N,5-dimethoxy-N-methyl-4-oxo-1-[3-(trifluoromethyl)phenyl]-1,4-dihydropyridazine-3-carboxamide (2.09 g, 5.85 mmol) in THF (50 mL). After stirring for 1 h, the reaction mixture was quenched with saturated NH4Cl aqueous solution and extracted with AcOEt three times. The combined extracts were washed with brine, dried over MgSO4, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography eluting with AcOEt/MeOH (1/0-10/1) and recrystallized from hexane/AcOEt to give the title compound (1.44 g, 79% yield) as off-white crystals: mp 155-156° C.; 1H NMR (300 MHz, CDCl3): δ ppm 2.71 (3H, s), 3.98 (3H, s), 7.68-7.76 (2H, m), 7.83-7.88 (2H, m), 7.94 (1H, s). Anal. Calcd for C14H11F3N2O3: C, 53.85; H, 3.55; N, 8.97. Found: C, 53.79; H, 3.59; N, 9.02.

Provenance & Evidence