反应详情

To a solution of methyl 2,3-dihydrobenzo[b][1,4]dioxine-6-carboxylate (780 mg, 4.0 mmol) in acetic acid (3 mL) was added dropwise conc. HNO3 (4 mL) while keeping the temperature below 20° C. and the resulting reaction mixture was warmed to room temperature. After stirring for 1 hr, the mixture was poured onto ice-water with vigorous stirring. The resulting white precipitate was collected by vacuum filtration and dried under reduced pressure to yield methyl 7-nitro-2,3-dihydrobenzo[b][1,4]dioxine-6-carboxylate (889 mg, 92%). 1H NMR (DMSO-d6, 600 MHz) δ 7.64 (s, 1H), 7.30 (s, 1H), 4.41-4.38 (m, 4H), 3.80 (s, 3H); MS (ES+) m/z 240.0 (M+H)+

1. customthe temperature below 20° C.
2. customthe resulting reaction mixture
3. additionthe mixture was poured onto ice-water with vigorous stirring
4. filtrationThe resulting white precipitate was collected by vacuum filtration
5. customdried under reduced pressure