反应详情

A solution of N-bromosuccinimide (2.32 g, 13.0 mmol) in DMF (20 ml) was added to a cold (−20° C.) solution of 1b (2.76 g, 11.4 mmol) in DMF (25 ml). The reaction rapidly turned dark red. HPLC analysis after 5 min showed that the reaction was complete. The reaction was quenched with a freshly prepared solution of sodium thiosulfate (40 ml, 10% aqueous). A precipitate formed. The mixture was warmed to rt and was diluted with water (60 ml). The solid was filtered, washed with water and dried overnight under reduced pressure to give 123a (3.82 g, 96% yield) as brown solid. [M+H]+=321.14. 1H NMR (500 MHz, CDCl3) δ ppm 1.40 (s, 9H), 3.91 (s, 2H), 6.93 (m, 2H), 7.00 (d, J=8.07 Hz, 1H), 7.12 (t, J=7.73 Hz, 1H), 7.20 (t, J=7.73 Hz, 1H), 7.41 (d, J=8.07 Hz, 1H).

1. customThe reaction rapidly turned dark red
2. customThe reaction was quenched with a freshly prepared solution of sodium thiosulfate (40 ml, 10% aqueous)
3. customA precipitate formed
4. filtrationThe solid was filtered
5. washwashed with water
6. customdried overnight under reduced pressure