Tert-Butyl nitrite → 6-Bromo-5-fluorobenzo[d]thiazole
反応式
[Br:1][C:2]1[C:11]([F:12])=[CH:10][C:5]2[N:6]=[C:7](N)[S:8][C:4]=2[CH:3]=1.C(ON=O)(C)(C)C>CN(C=O)C>[Br:1][C:2]1[C:11]([F:12])=[CH:10][C:5]2[N:6]=[CH:7][S:8][C:4]=2[CH:3]=1参加物
4
反応条件
- 温度
- 50 °C
実験手順
To a solution of 6-bromo-5-fluoro-benzothiazol-2-ylamine (2.73 g, 11.05 mmol) in DMF (60 mL) was added tert-butylnitrite (1.58 mL, 13.26 mmol) dropwise. The reaction mixture was stirred at 50° C. for 3 h, then it was concentrated in vacuo. The residue was stirred in 1 N aqueous KOH for 10 min, then ethyl acetate was added and the mixture was stirred overnight. The insolubles were filtered, washed with water then ethyl acetate. The resulting filtrate was separated, and the organic layer was washed with brine and directly adsorbed on silica gel. Purification by flash chromatography on silica gel using a gradient of 0-30% ethyl acetate/hexane afforded 1.33 g of 6-bromo-5-fluoro-benzothiazole as a light yellow solid (52% yield): 1H NMR (DMSO-d6) δ 8.13 (d, 1H), 8.63 (d, 1H), 9.50 (s, 1H); MS (m/z) 232, 234 [M+H+]+.