反应详情

温度

60 °C

To 10 ml of anhydrous toluene, there were added 0.93 g of the (2R, 4R)-4-hydroxy-1-(2-nitrophenyl) proline methyl ester prepared in Reference Example 6, 1.8 g of triphenyl phosphine, 0.42 g of acetic acid and 0.25 g of triethylamine and then 1.4 g of diisopropyl azodicarboxylate was dropwise added to the resulting mixture over one hour with ice-cooling. After stirring the mixture for 16 hours with heating to 60° C. and cooling it to room temperature, 8 ml of a 1.3N sodium hydroxide solution was added to the mixture, followed by stirring the mixture for additional 4 hours at room temperature. The pH of the reaction solution was adjusted to 7 with concentrated hydrochloric acid, the insolubles precipitated were filtered off, the resulting filtrate was fractionated and the aqueous phase obtained was washed with ether. Then the aqueous phase was acidified with hydrochloric acid, followed by extraction with ethyl acetate, washing with water and drying over anhydrous magnesium sulfate. After concentration of the ethyl acetate extract, the resulting residue was recrystallized from ethyl acetate-chloroform to give 0.66 g (yield 74.8%) of the title compound.

1. temperaturecooling
2. temperaturecooling it to room temperature
3. stirringby stirring the mixture for additional 4 hours at room temperature
4. customthe insolubles precipitated
5. filtrationwere filtered off
6. customthe aqueous phase obtained
7. washwas washed with ether
8. extractionfollowed by extraction with ethyl acetate
9. washwashing with water
10. dry with materialdrying over anhydrous magnesium sulfate
11. extractionAfter concentration of the ethyl acetate extract
12. customthe resulting residue was recrystallized from ethyl acetate-chloroform