反应详情

1.89 g (45.2 mmol) of sodium hydride (as a 55% w/w dispersion in mineral oil) were added, whilst ice-cooling, to a solution of 10.0 g (41.1 mmol) of 4-(benzyloxycarbonylamino)phenol [prepared as described in step (a) above] in 100 ml of dimethylformamide, and the mixture was stirred for 5 minutes. 5.01 ml (45.2 mmol) of ethyl bromoacetate were then added to the resulting mixture, after which the mixture was stirred at room temperature for 3 hours. At the end of this time, the reaction mixture was neutralized with 1N aqueous hydrochloric acid, and the solvent was removed by distillation under reduced pressure. The residue was mixed with ethyl acetate, and the resulting organic solution was washed with a 5% w/v aqueous solution of citric acid, with a 5% w/v aqueous solution of sodium hydrogencarbonate and with a saturated aqueous solution of sodium chloride, in that order. The reaction mixture was then dried over anhydrous sodium sulfate, and the organic solvent was removed by distillation under reduced pressure. The residue was purified by column chromatography through silica gel, using a gradient elution method, with mixtures of hexane and ethyl acetate in ratios ranging from 10:1 to 6:1 by volume as the eluent, to give 11.7 g of the title compound as colorless crystals, melting at 85°-86° C.

1. stirringafter which the mixture was stirred at room temperature for 3 hours
2. customthe solvent was removed by distillation under reduced pressure
3. additionThe residue was mixed with ethyl acetate
4. washthe resulting organic solution was washed with a 5% w/v aqueous solution of citric acid, with a 5% w/v aqueous solution of sodium hydrogencarbonate and with a saturated aqueous solution of sodium chloride, in that order
5. dry with materialThe reaction mixture was then dried over anhydrous sodium sulfate
6. customthe organic solvent was removed by distillation under reduced pressure
7. customThe residue was purified by column chromatography through silica gel
8. washa gradient elution method