Réaction #2146705

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 refluxed for 70 minutes
2. 2
   FiltrationThen, palladium-carbon was filtered off
3. 3
   Lavagewhich was then washed with ethanol
4. 4
   ConcentrationAfter the resulting solution was concentrated under reduced pressure
5. 5
   Extractionextracted eight times with chloroform
6. 6
   SéchageThe combined chloroform layer was dried over anhydrous sodium sulfate
7. 7
   Concentrationconcentrated under reduced pressure
8. 8
   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. Then, 283 mL of hydrazine monohydrate was added dropwise. After the reaction mixture was refluxed for 70 minutes, the reaction solution was cooled down to room temperature. Then, palladium-carbon was filtered off, which was then washed with ethanol. The washings were combined with the filtrate. After the resulting solution was concentrated under reduced pressure, the concentrate was supplemented with 1300 mL of water and 130 mL of conc. aqueous ammonia, and extracted eight times with chloroform. The combined chloroform layer was 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. 1, Step 3).

Source