Phosphorus tribromide → 4-Bromo-7-(4-methoxy-2-methylphenyl)-2,6-dimethylpyrrolo[1,2-b]pyridazine

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Reaction Steps

A solution of 7-(4-methoxy-2-methylphenyl)-2,6-dimethylpyrrolo[1,2-b]pyridazin-4-ol (0.16 g, 0.567 mmol) and phosphorus tribromide (0.27 mL, 2.83 mmol) in bromobenzene (3.0 mL) was refluxed for 5 h. After cooling down to room temperature, the mixture was diluted with CHCl3. Saturated NaHCO3 solution was added to neutralize and separated immediately. The aqueous layer was extracted with CHCl3 (2×). The combined CHCl3 solution was dried over MgSO4 and filtered. The filtrate was concentrated in vacuo to dryness. The residue was subjected to column chromatography (silica gel, 1/20 EtOAc/hexane) to afford 0.14 g (64%) of light yellow oil as the title compound: 1H NMR (400 MHz, CDCl3) δ 7.12 (d, J=8 Hz, 1H), 6.82 (d, J=3 Hz, 1H), 6.76 (dd, J=3, 8 Hz, 1H), 6.59 (s, 1H), 6.49 (s, 1H), 3.79 (s, 3H), 2.28 (s, 3H), 2.12 (s, 3H), 1.98 (s, 3H); MS m/z 347.1 (M++H).

Provenance & Evidence