反应详情

A 250 mL round bottom flask was charged with 3 (10 g, 34 mmol) and was then placed in an ice bath. To this was added a 20% v/v solution of fuming nitric acid in acetic acid (40 mL total volume) at a rate of 1.0 mL/minute with stirring. At the end of addition the bath was removed, the reaction was protected from light, and stirred at room temperature for 4 hours. At this time the solution was poured over crushed ice (200 mg). Water was added and the product was extracted with ethyl acetate (3×200 mL). The combined organics were washed with brine (1×200 mL), saturated sodium bicarbonate (1×200 mL), and water (1×200 mL), dried over magnesium sulfate, and filtered. The solvent was evaporated in vacuo to give 10.6 g of 4 (92%) as an orange-red solid. Rf=0.80 (33% ethyl acetate/hexane). Mp 79.8-81.5° C. 1H NMR (400 MHz, DMSO-d6): δ7.69 (s, 1), 7.37 (s,1), 4.17 (pt, J=6.4, 6.8 Hz, 2), 4.0 (t, J=6.8 Hz, 2), 3.95 (s,3), 1.99 (s, 3), 1.77 (m, 2), 1.59 (m, 2), 1.45-1.37 (m, 4) ppm.

1. customwas then placed in an ice bath
2. additionAt the end of addition the bath
3. customwas removed
4. stirringstirred at room temperature for 4 hours
5. additionAt this time the solution was poured
6. customover crushed ice (200 mg)
7. additionWater was added
8. extractionthe product was extracted with ethyl acetate (3×200 mL)
9. washThe combined organics were washed with brine (1×200 mL), saturated sodium bicarbonate (1×200 mL), and water (1×200 mL)
10. dry with materialdried over magnesium sulfate
11. filtrationfiltered
12. customThe solvent was evaporated in vacuo