Reaktion #72249

Reaktionsgleichung

ethyl 2-amino-3-bromo-5-methylbenzoate

Ethyl 2-amino-3-bromo-5-methylbenzoate

trifluoroacetic acid

isopentyl nitrite

hypophosphorous acid

→

title compound

Ausbeute 87.3%

Ethyl 3-bromo-5-methylbenzoate

Ausbeute 87.3%

Lösungsmittel

Ethanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturcooling
2. 2
   workup.STIRRINGby stirring at room temperature for 30 minutes
3. 3
   workup.ADDITIONThe reaction solution was diluted
4. 4
   Extraktionextracted with ethyl acetate and aqueous sodium bicarbonate solution
5. 5
   WaschenThe organic layer was washed with water and brine
6. 6
   Trocknendried over anhydrous magnesium sulfate
7. 7
   Einengenconcentrated under reduced pressure
8. 8
   SonstigeThe residue was purified by silica gel column chromatography (elution solvent: ethyl acetate/hexane=0/10, 2/8)

Vorschrift

Ethanol (20 mL) was added to ethyl 2-amino-3-bromo-5-methylbenzoate obtained in Example (259d) (715 mg, 2.8 mmol). While the mixture was stirred, trifluoroacetic acid (0.82 mL, 11.1 mmol), isopentyl nitrite (649 mg, 5.5 mmol) and hypophosphorous acid (7.3 g, 55.4 mmol) were added under ice-cooling, followed by stirring at room temperature for 30 minutes. The reaction solution was diluted and extracted with ethyl acetate and aqueous sodium bicarbonate solution. The organic layer was washed with water and brine, dried over anhydrous magnesium sulfate, and then concentrated under reduced pressure. The residue was purified by silica gel column chromatography (elution solvent: ethyl acetate/hexane=0/10, 2/8) to obtain 594 mg of the title compound as a light yellow oily substance (88%).

Quelle