Reaktion #435024

Reaktionsgleichung

sodium nitrite

7-bromo-2-methoxypyrazolo[1,5-a]pyridine

ethanol

water

→

title compound

Ausbeute 70.3%

7-Bromo-2-methoxypyrazolo[1,5-a]pyridine-3-amine

Ausbeute 70.3%

Lösungsmittel

acetic acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwas added
2. 2
   Temperaturthe reaction mixture was heated
3. 3
   workup.STIRRINGstirred for 30 minutes at 60° C
4. 4
   FiltrationThe reaction mixture was filtered through celite
5. 5
   Sonstigeto remove insoluble residue, water
6. 6
   workup.ADDITIONwas added
7. 7
   Extraktionextraction
8. 8
   ExtraktionThe organic extract
9. 9
   Waschenwas washed with brine
10. 10
    Trocknendried over anhydrous magnesium sulfate
11. 11
    Filtrationfiltered
12. 12
    Sonstigethe solvent was evaporated under reduced pressure
13. 13
    Sonstigethe residue was purified by silica gel column chromatography

Vorschrift

To a solution of 7-bromo-2-methoxypyrazolo[1,5-a]pyridine (1 g) dissolved in acetic acid (10 mL) was added an aqueous solution (5 mL) of sodium nitrite (334 mg), and the reaction mixture was stirred for 20 minutes at room temperature. After adding ethanol (60 mL) and water (30 mL) to the reaction mixture, zinc powder (1 g) was added and the reaction mixture was heated and stirred for 30 minutes at 60° C. The reaction mixture was filtered through celite to remove insoluble residue, water was added and extraction was performed with ethyl acetate. The organic extract was washed with brine, dried over anhydrous magnesium sulfate and filtered, the solvent was evaporated under reduced pressure, the residue was purified by silica gel column chromatography and the title compound (750 mg) was obtained as brown crystals from the n-hexane:ethyl acetate (3:1) fraction.

Quelle