Ammonium → 5-Bromoisoquinoline

Participants

Reaction Conditions

Reaction Steps

A solution of sodium nitrite (2.15 g, 31.21 mmol) in water (2 mL) was added to a solution of isoquinolin-5-ylamine (3.0 g, 20.80 mmol) in aqueous 46% hydrogen bromide (9.98 g, 124.84 mmol) at 0° C. The mixture was stirred at 0° C. for 30 min then a solution of cuprous bromide (3.58 g, 24.96 mmol) in aqueous 46% hydrogen bromide (9.98 g, 124.84 mmol) was added and the reaction was allowed to warm to ambient temperature and stirred for 2 h. The resulting mixture was basified with aqueous ammonium and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulphate and concentrated to afford the crude compound. Purification by column chromatography over silica gel (100-200 mesh) with 20% ethyl acetate in petroleum ether as eluent afforded 5-bromoisoquinoline (2.3 g, 53%) as a pale yellow solid.

Provenance & Evidence