反应详情

To a solution of ethyl 7-(2-amino-4-(tert-butoxycarbonyl)phenoxy)-6,8-dichlorochroman-4-carboxylate (2.1 g, 4.4 mmol) in 20 mL of DMF at 70° C. was added isobutyl nitrite (1.29 mL, 10.9 mmol) dropwise over ten minutes. After an additional 15 minutes the reaction was cooled to ambient temperature and poured into 600 mL of water. The product was extracted with ethyl acetate and the combined organics were washed with brine, dried over sodium sulfate, filtered and concentrated. The crude product was dissolved in dichloromethane, concentrated onto silica gel and purified by flash column chromatography, eluting with 20% ethyl acetate in hexanes to give ethyl 7-(4-(tert-butoxycarbonyl)phenoxy)-6,8-dichlorochroman-4-carboxylate (1.85 g, 90.9% yield) as a foam.

1. extractionThe product was extracted with ethyl acetate
2. washthe combined organics were washed with brine
3. dry with materialdried over sodium sulfate
4. filtrationfiltered
5. concentrationconcentrated
6. dissolutionThe crude product was dissolved in dichloromethane
7. concentrationconcentrated onto silica gel
8. custompurified by flash column chromatography
9. washeluting with 20% ethyl acetate in hexanes