Reaktion #67629

Reaktionsgleichung

phosphorous oxychloride

3-bromo-5-ethoxypyridine

→

5-bromo-2-chloro-3-ethoxypyridine

Ausbeute 85.6%

Lösungsmittel

brine

DCM

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigethe organics were partitioned
2. 2
   Trocknendried over MgSO4
3. 3
   Filtrationfiltered
4. 4
   Einengenthe filtrate concentrated under reduced pressure
5. 5
   SonstigeThe product was purified
6. 6
   Filtrationby filtering the
7. 7
   Einengenconcentrate through a pad of silica gel
8. 8
   Wascheneluting the pad with ethyl acetate
9. 9
   SonstigeThe volatiles were removed under reduced pressure

Vorschrift

As shown in step 2-iv of Scheme 2, phosphorous oxychloride (48.02 g, 403.6 mmol) was added to 3-bromo-5-ethoxypyridine, 1-oxide (4.4 g, 20.18 mmol) in 700 mL of DCM at RT. The reaction mixture was stirred at RT overnight. After the addition of brine, the organics were partitioned, dried over MgSO4, filtered, and the filtrate concentrated under reduced pressure. The product was purified by filtering the concentrate through a pad of silica gel and eluting the pad with ethyl acetate. The volatiles were removed under reduced pressure to provide 5-bromo-2-chloro-3-ethoxypyridine (Compound 1003, 4.3 g, 85.6%): 1H NMR (CDCl3) δ 8.1 (s, 1H), 7.32 (s, 1H), 4.15 (q, 2H), 1.6 (t, 3H).

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