Trifluoroacetic acid → 2,2-Dimethyl-6-nitro-2H,4H-1,3-benzodioxin-4-one

Participants

Reaction Steps

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 1:1H2O/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.

Provenance & Evidence