Dimethylformamide dimethyl acetal → 3-[3-(Dimethylamino)prop-2-enoyl]-5-methoxy-1-[3-(trifluoromethyl)phenyl]pyridazin-4(1H)-one

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Reaction Steps

A solution of 3-acetyl-5-methoxy-1-[3-(trifluoromethyl)phenyl]pyridazin-4(1H)-one (1.39 g, 4.45 mmol) in N,N-dimethylformamide dimethyl acetal (15 mL) was refluxed for 3 h. After cooling to room temperature, the reaction mixture was concentrated under reduced pressure, and the residue was dissolved in AcOEt. The organic solution was washed with half-saturated brine, and the aqueous solution was extracted with AcOEt four times. The combined organic layers were dried over MgSO4, and concentrated under reduced pressure. The residue was recrystallized from AcOEt to give the title compound (1.46 g, 89% yield) as orange crystals: mp 176-178° C.; 1H NMR (300 MHz, CDCl3): δ ppm 2.91 (3H, s), 3.14 (3H, s), 3.96 (3H, s), 5.80 (1H, d, J=13.2 Hz), 7.61-7.68 (2H, m), 7.80 (1H, br s), 7.84-7.90 (2H, m), 7.96 (1H, s). Anal. Calcd for C17H16F3N3O3: C, 55.59; H, 4.39; N, 11.44. Found: C, 55.32; H, 4.51; N, 11.30.

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