反应详情

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%).

1. temperaturecooling
2. stirringby stirring at room temperature for 30 minutes
3. additionThe reaction solution was diluted
4. extractionextracted with ethyl acetate and aqueous sodium bicarbonate solution
5. washThe organic layer was washed with water and brine
6. dry with materialdried over anhydrous magnesium sulfate
7. concentrationconcentrated under reduced pressure
8. customThe residue was purified by silica gel column chromatography (elution solvent: ethyl acetate/hexane=0/10, 2/8)