反应详情

温度

80 °C

Potassium hydroxide (2.19 g, 33.2 mmol) was dissolved in Ethanol (150 mL) and 3-(3-Chloro-propyl)-5-nitro-3H-benzoxazol-2-one (8.11 g, 31.6 mmol) was added. After 2 h, the mixture was concentrated in vacuo, and the solids redissolved in N,N-Dimethylformamide (150 mL). The mixture was heated to 80° C. for 2 h. The mixture was cooled and diluted with 500 mL EtOAc and washed with water (4×50 mL). The aq. washes were back extracted with 100 mL EtOAc. The combined organics were washed with water (50 mL) and brine (100 mL), dried over sodium sulfate and conc. in vacuo to give orange solids, which were triturated in 10% Ether:Hexane (100 mL) overnight. The orange solids were collected and washed with hexane to furnish 2-Nitro-7,8-dihydro-6H-5-oxa-9-aza-benzocycloheptene-9-carboxylic acid ethyl ester (6.45 g, 77%). 1H-NMR (DMSO): 8.19 (s, 1H), 8.02 (d, 1H, J=8.9 Hz), 7.19 (d, 1H, J=8.9 Hz), 4.25 (m, 2H), 4.15 (m, 2H), 3.76 (m, 2H), 2.05 (m, 2H), 1.19 (m, 3H).

1. concentrationthe mixture was concentrated in vacuo
2. dissolutionthe solids redissolved in N,N-Dimethylformamide (150 mL)
3. temperatureThe mixture was cooled
4. additiondiluted with 500 mL EtOAc
5. washwashed with water (4×50 mL)
6. extractionThe aq. washes were back extracted with 100 mL EtOAc
7. washThe combined organics were washed with water (50 mL) and brine (100 mL)
8. dry with materialdried over sodium sulfate and conc. in vacuo
9. customto give orange solids, which
10. customwere triturated in 10% Ether
11. customHexane (100 mL) overnight
12. customThe orange solids were collected
13. washwashed with hexane