Hydrazine hydrate (1:1) → 2-Amino-5-methoxypyridine

17.36 g (corresponding to 74.50 mmol) of 2-bromo-3-methoxy-6-nitropyridine was dissolved in 520 mL of ethanol, and 11.63 g (50% wet) of 10% palladium-carbon was added thereto under argon atmosphere. To the mixture, 88.4 mL of hydrazine monohydrate was added dropwise. After the reaction mixture was refluxed for 45 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, 402 mL of water and 38 mL of conc. aqueous ammonia were added to the concentrate, and the resulting mixture was 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 8.14 g (corresponding to 65.57 mmol) of 2-amino-5-methoxypyridine (FIG. 5, Step 3).

1. temperatureAfter the reaction mixture was refluxed for 45 minutes
2. filtrationThen, after palladium-carbon was filtered off
3. washthe residue was washed with ethanol
4. concentrationThe combined solution was concentrated under reduced pressure
5. additionThen, 402 mL of water and 38 mL of conc. aqueous ammonia were added to the concentrate
6. extractionthe resulting mixture was extracted eight times with chloroform
7. dry with materialThe combined chloroform layer was dried over anhydrous sodium sulfate
8. concentrationconcentrated under reduced pressure
9. distillationThe resulting crude product was distilled under reduced pressure

ORD-Eintrag

ord-d7db121c79db40aab9ae0745955dc7ba

Quelldatensatz

uspto-grants-2011_09

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08022207B2