6-Bromo-1,2,4-triazine-3,5(2H,4H)-dione

5-Bromo-6-azouridine is mainly used as a pharmaceutical intermediate.

2H- [1, 2,4] triazin-3,5-dione (50 g, 442 mmol) is placed in 60 ml of bromine in 800 ml of water at 60°C for 10 h. The reaction medium is then run slowly onto an aqueous ammonia solution until pH = 5. It is then extracted with ethyl acetate and the organic phases are dried over MgS04. After filtration and concentration to dryness, 6-Bromo-1,2,4-triazine-3,5(2H,4H)-dione is isolated as a white solid (79.2 g, yield = 93 percent).

[1] Patent: WO2005/80354, 2005, A1. Location in patent: Page/Page column 19
[2] Patent: US2008/167313, 2008, A1. Location in patent: Page/Page column 7
[3] Patent: WO2004/74266, 2004, A1. Location in patent: Page 52
[4] Patent: WO2006/15985, 2006, A1. Location in patent: Page/Page column 62
[5] Bioorganic and Medicinal Chemistry Letters, 2017, vol. 27, # 8, p. 1727 - 1730