Hydrochloric Acid → 6-(2,6-Dibromo-4-chloromethyl-benzyl)-4-isopropyl-pyridazin-3-one

Participants

Reaction Conditions

Reaction Steps

A mixture of (6-chloro-5-isopropyl-pyridazin-3-yl)-[2,6-dibromo-4-(tetrahydro-pyran-2-yloxymethyl)-phenyl]-acetonitrile (61) (332.8 mg, 0.61 mmol) and sodium acetate (103.8 mg, 1.26 mmol) in glacial acetic acid (2.7 mL) was heated to reflux for 2.5 h. The reaction was then treated with concentrated hydrochloric acid (2.0 mL) and heated to reflux for 18 h. At this time, the reaction was treated with more concentrated hydrochloric acid (6.0 mL) and additional glacial acetic acid (3.0 mL) and heated to reflux for an additional 24 h. The reaction was then cooled to 25° C. and diluted with ethyl acetate (150 mL). This solution was washed with a saturated aqueous sodium chloride solution (2×50 mL) and a saturated aqueous sodium carbonate solution (1×100 mL), dried with magnesium sulfate, filtered, and concentrated under vacuum. The resulting brown oil was treated with glacial acetic acid (1.0 mL) and concentrated hydrochloric acid (6.0 mL) and was heated to reflux for 3 d. At this time, the reaction was cooled to 25° C. and diluted with ethyl acetate (150 mL). This solution was washed with a saturated aqueous sodium chloride solution (2×50 mL) and a saturated aqueous sodium carbonate solution (1×100 mL), dried with magnesium sulfate, filtered, and concentrated under vacuum. Flash chromatography (Merck Silica gel 60, 230-400 mesh, 2/1 hexanes/ethyl acetate) afforded 6-(2,6-dibromo-4-chloromethyl-benzyl)-4-isopropyl-pyridazin-3-one (62) (96.3 mg, 36%) as an off-white solid; LRMS for C15H15Br2ClN2O (M+H) at m/z=433. Molecular Weight=434.5606; Exact Mass=431.9240

Provenance & Evidence