反応 #2162351

反応方程式

benzoyl peroxide

Benzoyl peroxide

2-chloro-3-fluoro-5-methylpyridine

NBS

→

5-(bromomethyl)-2-chloro-3-fluoropyridine

溶媒

CCl4

反応条件

後処理

1. 1
   workup.WAITthe stirring was continued for 1 hour
2. 2
   ろ過filtered
3. 3
   洗浄the solid was washed with dichloromethane
4. 4
   洗浄The combined filtrates was washed with water
5. 5
   乾燥dried over anhydrous sodium sulfate
6. 6
   濃縮concentrated on a rotary evaporator
7. 7
   その他The crude product was purified by silica gel column chromatography (hexane/ethyl acetate)

実験手順

Benzoyl peroxide (100 mg, 41 mmol) was added to a refluxing mixture of 2-chloro-3-fluoro-5-methylpyridine (5.0 g, 34.35 mmol) and NBS (6.73 g, 37.79 mmol) in CCl4 (180 mL). After stirring the mixture for 15 minutes, an additional amount of benzoyl peroxide (400 mg, 1.65 mmol) was added in four portions over a period of 1 hour and the stirring was continued for 1 hour. The reaction mixture was cooled to room temperature, filtered and the solid was washed with dichloromethane. The combined filtrates was washed with water, dried over anhydrous sodium sulfate and concentrated on a rotary evaporator. The crude product was purified by silica gel column chromatography (hexane/ethyl acetate) to afford 5-(bromomethyl)-2-chloro-3-fluoropyridine: 1H NMR (400 MHz, CDCl3) δ 8.23 (d, J=2.0 Hz, 1H), 7.55 (dd, J=2.0, 8.8 Hz, 1H), 4.45 (s, 2H).

出典