Réaction #2036054

Équation de réaction

2-bromo-3-methoxy-6-nitropyridine

hydrazine monohydrate

→

2-amino-5-methoxypyridine

Rendement 88.3%

Solvants

ethanol

Conditions de réaction

Traitement

1. 1
   TempératureAfter the reaction mixture was heated
2. 2
   Températureunder reflux for 70 minutes
3. 3
   FiltrationThen, after palladium-carbon was filtered off
4. 4
   Lavagethe residue was washed with ethanol
5. 5
   ConcentrationThe combined solution was concentrated under reduced pressure
6. 6
   workup.ADDITIONThen, 1300 mL of water and 130 mL of conc. aqueous ammonia were added to the concentrate
7. 7
   Extractionthe resulting mixture was extracted eight times with chloroform
8. 8
   SéchageThe combined chloroform layers were dried over anhydrous sodium sulfate
9. 9
   Concentrationconcentrated under reduced pressure
10. 10
    workup.DISTILLATIONThe resulting crude product was distilled under reduced pressure

Mode opératoire

55.6 g (corresponding to 0.239 mol) of 2-bromo-3-methoxy-6-nitropyridine was dissolved in 1700 mL of ethanol, and 37.3 g (50% wet) of 10% palladium-carbon was added thereto under argon stream. To the mixture, 283 mL of hydrazine monohydrate was then added dropwise. After the reaction mixture was heated under reflux for 70 minutes, the reaction solution was cooled down to room temperature. Then, after palladium-carbon was filtered off, the residue was washed with ethanol, and the washings were combined with the filtrate. The combined solution was concentrated under reduced pressure. Then, 1300 mL of water and 130 mL of conc. aqueous ammonia were added to the concentrate, and the resulting mixture was extracted eight times with chloroform. The combined chloroform layers were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The resulting crude product was distilled under reduced pressure to obtain 26.2 g (corresponding to 0.211 mol) of 2-amino-5-methoxypyridine (FIG. 3, Step 3).

Source