反应详情

A solution of 12.50 g of 85% potassium hydroxide (i.e. potassium hydroxide of purity about 85%, of which the main impurity is water) dissolved in a mixture of 20 ml of water and 30 ml of methanol was added dropwise, whilst ice-cooling, to a solution of 10.87 g of ethyl N-[2-(3-chloro-4-ethoxycarbonyloxyphenyl)-1-methyl-2-oxoethyl]carbamate [prepared as described in step (a) above] in 130 ml of methanol over a period of 5 minutes. The mixture was then stireed at room temperature for 20 minutes. At the end of this time, the mixture was concentrated by evaporation under reduced pressure and then acidified with 5% w/v aqueous hydrochloric acid. It was then extracted with ethyl acetate. The extract was washed with a saturated aqueous solution of sodium chloride and dried. The ethyl acetate of the solvent was then removed by evaporation under reduced pressure. The residue was recrystallized from a mixure of ethyl acetate and hexane, to give 6.12 g of the title compound as a yellowish-brown powder melting at 106°-108° C.

1. additionwas added dropwise, whilst ice-
2. concentrationAt the end of this time, the mixture was concentrated by evaporation under reduced pressure
3. extractionIt was then extracted with ethyl acetate
4. washThe extract was washed with a saturated aqueous solution of sodium chloride
5. customdried
6. customThe ethyl acetate of the solvent was then removed by evaporation under reduced pressure
7. customThe residue was recrystallized from a mixure of ethyl acetate and hexane