1,3-Dibromo-5,5-dimethylhydantoin → 5-Bromopyrrolo[2,1-f][1,2,4]triazin-4-amine

Participants

Reaction Steps

A suspension of pyrrolo[2,1-f][1,2,4]triazin-4-amine (0.5 g, 0.004 mol) in dichloromethane (100 mL) was stirred and cooled between −10° C. and −14° C. under nitrogen atmosphere. A solution of 1,3-dibromo-5,5-dimethylimidazolidine-2,4-dione (544 mg, 0.002 mol) in dichloromethane (100 mL) added dropwise over a 1 h. After 4 h, 100 mL of 10% aqueous sodium thiosulfate solution was added, and the mixture was stirred vigorously for a few minutes. The phases were separated, the dichloromethane phase washed with water, then brine, dried (anhydrous sodium sulfate), filtered and concentrated in vacuo. The residue was purified by MPLC (dichloromethane/ethyl acetate gradient). Purified material was triturated with dichloromethane, filtered, washed and dried under vacuum to afford 289 mg (36%) of colorless, fluffy solid. 1H-NMR (DMSO-d6): δ 8.01 (br s, 1 H), 7.82 (s, 1 H), 7.70 (d, 1 H), 6.78 (d, br s, 2 H). MS: LC/MS (+esi), m/z=212.5, 213.1 [M+H]. RT=1.34 min. Calc. for C6H5BrN4: C, 33.83; H, 2.37; Br, 37.50; N, 26.3. Found: C, 33.85; H, 2.24; Br, 38.24; N, 26.21.

Provenance & Evidence