Reaktion #313190

Reaktionsgleichung

5-fluoro-3-methylbenzo[b]thiophene

NBS

→

2-Bromo-5-fluoro-3-methylbenzo[b]thiophene

Lösungsmittel

water

acetonitrile

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeto 17° C
2. 2
   Temperaturat which time the reaction is cooled to 18-20° C. by application of an ice water bath
3. 3
   workup.STIRRINGThe slurry is stirred for 10 min
4. 4
   Filtrationthe product is filtered
5. 5
   Waschenwashed with 50:50 acetonitrile
6. 6
   Trocknenwater (100 mL) and dried to a colorless crystalline solid (65.56 g, 88%)

Vorschrift

A mechanically-stirred solution of 5-fluoro-3-methylbenzo[b]thiophene (50.32 g, 0.303 mol, 1.0 equiv) in acetonitrile (350 mL) is treated with NBS (56.32 g, 0.318 mol, 1.05 equiv). An initial endotherm reduces the reaction temperature to 17° C. A subsequent exotherm then increases the reaction temperature to 40° C. over a 10 min. period, at which time the reaction is cooled to 18-20° C. by application of an ice water bath. The reaction is stirred at RT for an additional 35 min. and the resultant slurry is slowly diluted with water (350 mL). The slurry is stirred for 10 min and the product is filtered, washed with 50:50 acetonitrile:water (100 mL) and dried to a colorless crystalline solid (65.56 g, 88%).

Quelle