反应详情

A mixture of benzyl 3-(2-hydroxy-3-(methoxycarbonyl)phenylcarbamoyl)azetidine-1-carboxylate (820 mg, 2.13 mmol) in propionic acid (20 ml) was stirred at reflux for 2 days. Then the mixture was adjusted pH=7 by sodium bicarbonate. The mixture was extracted with ethyl acetate. The extraction was washed with sodium bicarbonate, brine, dried with sodium sulfate. The residue was removed in vacuum. The crude was purified by chromatography (silica gel, petroleum ether/ethyl acetate=5:1). 280 mg of methyl 2-(1-(benzyloxycarbonyl)azetidin-3-yl)benzo[d]oxazole-7-carboxylate as a solid was obtained, yield 39%. LC-MS (ESI) m/z: 367 (M+1)+.

1. temperatureat reflux for 2 days
2. extractionThe mixture was extracted with ethyl acetate
3. extractionThe extraction
4. washwas washed with sodium bicarbonate, brine
5. dry with materialdried with sodium sulfate
6. customThe residue was removed in vacuum
7. customThe crude was purified by chromatography (silica gel, petroleum ether/ethyl acetate=5:1)