反应详情

温度

90 °C

A mixture of ethyl 2-(6-hydroxy-3-oxo-2,3-dihydro-benzo[1,4]oxazin-4-yl)-propionic acid ethyl ester (1.08 g, 4.07 mmol), 3-methanesulfonyloxy-azetidine-1-carboxylic acid tert-butyl ester (1.12 g, 4.48 mmol) and Cs2CO3 (2.65 g, 8.12 mmol) in DMF (20 mL) was stirred at 90° C. for 3 h. The reaction mixture was cooled to ambient temperature and poured into water (150 mL). The aqueous mixture was extracted with EtOAc (3×20 mL) and the combined organic phase was washed with brine (50 mL), dried over anhydrous Na2SO4, filtered and evaporated in vacuo. The residue was purified by column chromatography on silica gel (eluting with 10% EtOAc in petroleum ether) to give 3-[4-(1-ethoxycarbonyl-ethyl)-3-oxo-3,4-dihydro-2H-benzo[1,4]oxazin-6-yloxy]-azetidine-1-carboxylic acid tert-butyl ester as a white solid (0.7 g, 41%). 1H NMR (CDCl3, 400 MHz): δ 6.94 (d, J=8.4 Hz, 1H), 6.30 (m, 2H), 5.30 (q, J=7.2 Hz, 1H), 4.78 (m, 1H), 4.59 (d, J=15.2 Hz, 2H), 4.27 (m, 4H), 3.95 (m, 2H), 1.62 (d, J=7.2 Hz, 3H), 1.45 (s, 9H), 1.21 (t, J=7.2 Hz, 3H).

1. temperatureThe reaction mixture was cooled to ambient temperature
2. extractionThe aqueous mixture was extracted with EtOAc (3×20 mL)
3. washthe combined organic phase was washed with brine (50 mL)
4. dry with materialdried over anhydrous Na2SO4
5. filtrationfiltered
6. customevaporated in vacuo
7. customThe residue was purified by column chromatography on silica gel (eluting with 10% EtOAc in petroleum ether)