Sulfuric Acid → 8-methyl-6-nitro-2,4-dihydro-1H-3,1-benzoxazine-2,4-dione

Participants

Reaction Conditions

Reaction Steps

Potassium nitrate (1.43 g, 14.1 mmole) was added in small portions at <30° C. with external water-bath cooling to a solution of 3-methyl isatoic anhydride (2.50 g, 14.1 mmole) and concentrated sulfuric acid (8 mL). The resulting mixture was stirred at 25° C. for 1.5 hours and then was poured into approximately 200 g of ice with stirring. After the ice had melted, the solid product was isolated by filtration and washed with dilute aqueous HCl and then air-dried. The product was suspended in acetonitrile (50 mL) and concentrated in vacuo to give 2.75 of a yellow solid. 1H NMR (DMSO-d6): δ 11.6 (br s, 1H), 8.45 (d, 1H), 8.42 (d, 1H), 2.43 (s, 3H).

Provenance & Evidence