Chloroform → 4-Bromo-6,7-dimethoxycinnoline

Participants

Reaction Conditions

Reaction Steps

Phosphorus oxybromide (125 g, 0.436 mol) was added to a suspension of 6,7-dimethoxycinnolin-4-ol (65 g, 0.32 mol) in chloroform (550 mL, 6.9 mol). The reaction mixture was stirred at 65° C. for 18 hours. Formation of a fine yellow solid was observed. The reaction mixture was poured onto crushed ice (200 g), and the pH was adjusted to 6-7 with sodium acetate (285 g) and sat. NaHCO3. The organic layer was separated, and the aqueous layer was extracted with dichloromethane (2×200 mL). The combined organic extracts were washed with brine (2×100 mL), dried over Na2SO4, filtered, and concentrated in vacuo to provide a light tan oil. DCM (40 mL) and hexanes (250 mL) were added, and the resulting solid was filtered to provide 4-bromo-6,7-dimethoxycinnoline as an off-white solid.

Provenance & Evidence