反应详情

To a solution of 1-(benzyloxycarbonyl)azetidine-3-carboxylic acid (2.4 g) in dichloride methane (15 ml) was added 1-hydroxybenzotriazole (1.48 mg, 11 mmol), diisopropylethylamine (4 g, 30 mmol) and 1-ethly-3-(3-dimethylaminopropyl)carbodiimide hydrochloric (2 g, 11 mmol). The mixture was stirred at room temperature for 30 min. Then ethyl 3-amino-2-hydroxybenzoate (700 mg, 4 mmol) was added. The mixture was stirred at room temperature for 2 h. To the resulting mixture, water (10 ml) was added and hydrochloride acid (1N) to pH=3, then extracted with ethyl acetate (100 ml×4). The organic phase was washed with sodium bicarbonate (saturated) and brine and concentrated, dried with sodium sulfate. The crude was purified by column chromatography (silica gel, petroleum ether/ethyl acetate=20:1). 820 mg of benzyl 3-(2-hydroxy-3-(methoxycarbonyl)phenylcarbamoyl)azetidine-1-carboxylate was obtained. Yield 52%. LC-MS (ESI) m/z: 385 (M+1)+.

1. stirringThe mixture was stirred at room temperature for 2 h
2. extractionhydrochloride acid (1N) to pH=3, then extracted with ethyl acetate (100 ml×4)
3. washThe organic phase was washed with sodium bicarbonate (saturated) and brine
4. concentrationconcentrated
5. dry with materialdried with sodium sulfate
6. customThe crude was purified by column chromatography (silica gel, petroleum ether/ethyl acetate=20:1)