Hydrochloric Acid → 6-Bromo-4-cinnolinol

Participants

Reaction Conditions

Reaction Steps

A solution of Example 34B (6.28 g, 24.4 mmol) in THF (75 mL) was treated with concentrated HCl (aq.) (15 mL) and water (15 mL), heated to reflux for 1 hour, and concentrated to remove the THF. The aqueous solution was treated with additional water (5 mL) and concentrated HCl (5 mL), cooled to 0° C., treated with a solution of NaNO2 (1.85 g, 26.84 mmol) in water (10 mL) in 5 portions, warmed to room temperature gradually over a 2-hour period, and stirred overnight at room temperature. The reaction was heated to reflux for 6 hours, and filtered. The solid was washed with water (50 mL) and diethyl ether (50 mL) and dried under vacuum to provide the desired product (3.0 g, 54%).

Provenance & Evidence