反应详情

5-Nitrosalicylic acid (25 g, 136.6 mmol) was taken up in acetone (20 ml) and trifluoroacetic acid (150 ml) and trifluoroacetic anhydride (50 ml) were added. The mixture was heated at reflux. After 1 hr more acetone (30 ml) was added, and the reaction was heated at reflux for 48 hrs. The reaction was cooled to RT and the volatiles were removed in vacuo. The resulting brown oil was dissolved in CH2Cl2 (400 ml) and washed with 1:1 H2O/saturated NaHCO3 (400 ml). The aqueous phase was extracted with CH2Cl2 (2×200 ml), and the combined organic layers were dried (MgSO4) and evaporated in vacuo. The solid residue was triturated with pentane (150 ml), collected by filtration, washed thoroughly with pentane and dried in vacuo to give 6-nitro-2,2-dimethyl-4H-benzo[1,3]dioxin-4-one (27.84 g, 91%) as a dark yellow solid.

1. temperatureThe mixture was heated
2. temperatureat reflux
3. temperaturethe reaction was heated
4. temperatureat reflux for 48 hrs
5. customthe volatiles were removed in vacuo
6. dissolutionThe resulting brown oil was dissolved in CH2Cl2 (400 ml)
7. washwashed with 1:1 H2O/saturated NaHCO3 (400 ml)
8. extractionThe aqueous phase was extracted with CH2Cl2 (2×200 ml)
9. dry with materialthe combined organic layers were dried (MgSO4)
10. customevaporated in vacuo
11. customThe solid residue was triturated with pentane (150 ml)
12. filtrationcollected by filtration
13. washwashed thoroughly with pentane
14. customdried in vacuo