反应详情

To the title compound of step 4 (100 mg, 0.7 mmol) in CH3CN (5 mL) was added NBS (154 mg, 0.8 mmol) at 20° C. After 2 h, the mixture was concentrated in vacuum at 45° C. Purification by silica gel chromatography (PE:EA=5:12:1) to gave the title compound (70 mg, yield: 45%) as a yellow solid. 1H NMR (CDCl3, 400 MHz) δ 8.04 (s, 1H), 7.52 (s, 1H), 3.69 (s, 3H).

1. concentrationthe mixture was concentrated in vacuum at 45° C
2. customPurification by silica gel chromatography (PE:EA=5:12:1)