[Cl:1][C:2]1[N:3]=[CH:4][C:5]([NH2:8])=[N:6][CH:7]=1.[Br:9]N1C(=O)CCC1=O>ClCCl>[Br:9][C:4]1[C:5]([NH2:8])=[N:6][CH:7]=[C:2]([Cl:1])[N:3]=1A 250 ml round bottom flask was charged with 5-chloro-pyrazin-2-ylamine (1) (3 g, 23 mmol, N-bromosuccinimide (4 g, 23 mmol) and dichloromethane (100 ml) under nitrogen. The reaction mixture was refluxed for 1 h, then allowed to cool to room temperature and concentrated in vacuo. The compound was purified by flash chromatography, using as eluent pentane/EtOAc 0% to 50%, to give the title compound (3 g, 62%). 1H NMR (DMSo-d6) 6.8-6.9 (2H, brs), 8.0 (1H, s). MS (ES+): 210, 212.
Wird geladen…