反应详情

Under an inert atmosphere, a mixture of 6-nitro-2,3-dihydro-4H-chromen-4-one (5.4 g, 28 mmol), ethanol (250 mL), Raney nickel (1.5 g) and anhydrous hydrazine (8.8 mL, 0.28 mol) is stirred at ambient temperature overnight and filtered. The clear filtrate is concentrated to near dryness in vacuo. The resultant residue is treated with 6N hydrochloric acid and heated at reflux temperature for 1 hour, cooled in an ice bath, rendered basic with sodium bicarbonate and extracted with ethyl acetate. The organic phase is washed with brine, dried over MgSO4 and concentrated in vacuo to afford the title compound as a yellow crystalline solid, 3.4 g (75% yield), mp 136-137° C., identified by NMR and mass spectral analyses.

1. filtrationfiltered
2. concentrationThe clear filtrate is concentrated
3. additionThe resultant residue is treated with 6N hydrochloric acid
4. temperatureheated
5. temperatureat reflux temperature for 1 hour
6. temperaturecooled in an ice bath
7. extractionextracted with ethyl acetate
8. washThe organic phase is washed with brine
9. dry with materialdried over MgSO4
10. concentrationconcentrated in vacuo