反应详情

To a solution of compound 1-ethoxycarbonylmethylene-2-(6-chloro-3-pyridazinyl) hydrazine (11.4 g, 0.05 mol) and sodium acetate (11 g, 0.05 mol) in 50 mL of HOAc, bromine (8 g, 0.05 mol) in HOAc was added dropwise during 20 min. Stirring was continued for 3 h, the mixture was diluted with water (1 L), the precipitated crystals were filtered off, washed with water to give product ethyl 2-bromo-2-(2-(6-chloropyridazin-3-yl)hydrazono)acetate as a yellow solid (10 g, 66%). 1H NMR (300 MHz, d6-DMSO): δ 9.33 (br, 1H), 7.69-7.66 (d, J=9.0 Hz, 1H), 7.50-7.47 (d, J=9.0 Hz, 1H), 4.44-4.37 (q, 2H), 1.43-1.39 (t, 3H).

1. filtrationthe precipitated crystals were filtered off
2. washwashed with water