Bromine → HCID 19100713, compound

Participants

Reaction Steps

A suspension of 7-ethylthieno[2,3-b]pyrazine-2,3(1H,4H)-dione (1.0 g, 5.1 mmol) and sodium acetate (0.84 g, 10.2 mmol) in 225 ml of acetic acid was stirred at 10°-15° C. under a dry nitrogen atmosphere. A solution of bromine (0.26 ml, 5.1 mmol) in 2 ml of acetic acid was added during 0.5 h. Stirring was continued for further 0.5 h at room temperature and the reaction mixture was poured into ice water. The reddish mixture was decolourized by the addition of a small amount of aqueous sodium dithionite. The precipitate was filtered off, washed with water, resuspended in alcohol, filtered and washed with ether. Drying at 60° C. in vacuo afforded 720 mg (51%) of the title compound. M.p. 295°-297° C. 1H-NMR (DMSO-D6, δ): 1.04 (t, 3H), 2.62 (q, 2H), 12.01 (s, 1H), 12.19 (s, 1H).

Provenance & Evidence