Water → 4-Bromo-6-chloro-2,3-dihydropyridazin-3-one

Participants

Reaction Conditions

Reaction Steps

To a cooled solution (0-5° C.) of sodium nitrite (5.96 g, 86 mmol, Lobachem) in sulfuric acid (90 mL, 57.6 mmol) was added 4-bromo-6-chloropyridazin-3-amine (12 g, 57.6 mmol, Preparation #26) in acetic acid (300 mL). The mixture was stirred for 1 hr at about 20° C. and water was added (450 mL). The reaction mixture stirred for another 5 h at RT. The reaction mixture was extracted with EtOAc (3×200 mL), dried over sodium sulphate and evaporated on rotovapor. The residue obtained was purified by silica gel column chromatography by eluting with 50% EtOAc in hexane to afford 4-bromo-6-chloropyridazin-3(2H)-one 10 g, (83%) as pale yellow solids; 1H NMR (400 MHz, DMSO) δ 13.527 (s, 1H), 8.203 (s, 1H). MS m/z: 208.8 (M−H)−,

Provenance & Evidence