Bromine → Ethyl (3-oxo-2,3,-dihydropyridazin-6-yl)-propionate

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Reaction Steps

To a solution of ethyl (3-oxo-2,3,4,5-tetrahydropyridazin-6-yl)-propionate (50.0 mmol, 9.90 g) in ethanol (50 mL) was added bromine (75.0 mmol, 11.99 g). The mixture was stirred at rt for 14 h and the mixture was poored into NaHCO3 (sat. aqueous) (500 mL). The resulting mixture was extracted exhaustively with diethylether (5×500 mL). The combined organic fractions were dried over MgSO4 and evaporated in vacuo. The crude product was recrystallized from toluene to give the title compound (3.35 g, 34.1%) as colorless needles of high purity (HPLC at 260 nm). UV λmax 228 nm and 285 nm. 1H NMR (CDCl3): δ 11.62 (s br, 1H, NH), 7.18 (d, J=9.7 Hz, 1H, arom.), 7.88 (d, J=9.7 Hz, 1H, arom.), 4.11 (q, J=7.1 Hz, 2H, CH2), 2.90 (t, J=7.0 Hz, 2H, CH2), 2.64 (t, J=7.0 Hz, 2H, CH2), 1.25 (t, J=7.1 Hz, 3H, CH3). 13C NMR (CDCl3): δ 172.20, 161.50, 146.73, 134.06, 129.74, 60.45, 31.47, 25.89, 13.97. FAB+ MS: 197.10 (M+H+, calc. for C9H12N2O3+H+ 197.0926).

Provenance & Evidence