Bromine → 3-Bromoisothiazolo(4,5-b)pyrazine

Participants

Reaction Steps

Crude 3-mercaptopyrazine-2-carbonitrile (1.1 g, 8.0 mmol) was dissolved in ethyl acetate (30 mL) and treated with bromine (0.46 mL, 8.8 mmol). The reaction mixture was heated to reflux. As soon as the bromine was added, the mixture became homogeneous but after several minutes a precipitate began to form. After 90 min the reaction mixture was cooled to room temperature and then partitioned between ethyl acetate and saturated aqueous sodium bicarbonate solution. The organic layer was dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to yield 3-bromoisothiazolo[5,4-b]pyrazine as a pale orange solid. MW=215 confirmed by LC-MS, tr=10.34 min (Method Y) MH+=214-216.

Provenance & Evidence