Ethyl Acetate → 6-[3-Chloro-4-(ethoxycarbonylmethoxy)phenyl]-4,5-dihydro-3(2H)-pyridazinone

Beteiligte Stoffe

Reaktionsschritte

To a stirred suspension of 4-[3-chloro-4-(ethoxycarbonylmethoxy)phenyl]-4-oxobutyric acid (9, 21.5 g, 69.2 mmol) in ethanol (200 mL) at 0° C. was added a solution of hydrazine monohydrate (3.4 mL, 69.2 mmol) in ethanol (20 mL). The reaction mixture was then allowed to warm to ambient temperature and stirred at this temperature for 15 minutes before being heated to reflux and stirred at this temperature for 3 hours. Ethyl acetate (40 mL) was added to the hot solution and the mixture was allowed to cool to ambient temperature. The precipitate which formed was filtered off and washed with water (2×100 mL) and cold ethanol (2×100 mL), then dried with suction, then under high vacuum to give 10 as light yellow powder (17.6 g, 82% yield, 99% pure by LCMS and 1H NMR), 1H NMR (400 MHz; CDCl3): δ 7.52 (m, 1H); 7.41 (m, 1H); 6.70 (m, 1H); 4.90 (s, 2H); 4.12 (q, 2H); 2.22 (m, 2H); 1.62 (m, 2H); 1.30 (q, 3H).

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