Реакция #88043

Уравнение реакции

Na2CO3

3-iodo-4-methoxypyridin-2-amine

HBF4

NaNO2

→

2-fluoro-3-iodo-4-methoxypyridine

Растворители

H2O

Условия реакции

Обработка

1. 1
   workup.STIRRINGThe mixture was stirred at 0° C. for 3 h
2. 2
   ЭкстракцияThe layer was then extracted with EtOAc (×3)
3. 3
   СушкаThe combined organic layers were dried over anhydrous MgSO4
4. 4
   Фильтрацияfiltered
5. 5
   Концентрированиеconcentrated under vacuum
6. 6
   Другоеto leave a residue which
7. 7
   Другоеwas purified by column chromatography on silica gel (elution with 5:1 to 2:1 hexanes:ethyl acetate)

Методика

To a cold (−20° C.), stirred suspension of the 3-iodo-4-methoxypyridin-2-amine (2.5 g, 10 mmol) in HBF4 (70 mL, 470 mmol) was added an aqueous solution of NaNO2 (1.67 M, 6 mL, 10 mmol) over 20 min. The reaction turned green and then brown in color. The mixture was stirred at 0° C. for 3 h. The reaction was then carefully poured into a cold (0° C.) saturated solution of Na2CO3 (50 g) in H2O (100 mL). The layer was then extracted with EtOAc (×3). The combined organic layers were dried over anhydrous MgSO4, filtered, and concentrated under vacuum to leave a residue which was purified by column chromatography on silica gel (elution with 5:1 to 2:1 hexanes:ethyl acetate) to yield 2-fluoro-3-iodo-4-methoxypyridine as a light yellow solid.

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