Reaktion #590683

Reaktionsgleichung

4-Amino-2-chloropyridine

NBS

→

4-amino-3-bromo-2-chloropyridine

Lösungsmittel

acetic acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturcooling
2. 2
   Sonstigewas provided
3. 3
   SonstigeSolvent was removed under reduced pressure
4. 4
   workup.DISTILLATIONfollowed by azeotropic distillation with ethanol
5. 5
   SonstigeThe crude product was purified by column chromatography on silica gel (230-400 mesh)
6. 6
   Wascheneluting with ethyl acetate hexane mixture

Vorschrift

4-Amino-2-chloropyridine (50 g, 388 mmol) was dissolved in glacial acetic acid (500 mL). To this solution was added NBS (75 g, 426 mmol) portionwise at RT (water bath cooling was provided to control the exothermicity). The reaction mixture was stirred at RT for 1 h at which point the reaction was found complete (as monitored by TLC). Solvent was removed under reduced pressure followed by azeotropic distillation with ethanol. The crude product was purified by column chromatography on silica gel (230-400 mesh) eluting with ethyl acetate hexane mixture.

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