反应详情

A solution of 14.3 g. of 3-(4-chlorobenzoyl)-2-methylpropionic acid (Example 47), 7.26 g. of N-hydroxysuccinimide and 13 g. of dicyclohexylcarbidiimide in 150 ml. of dioxane is allowed to stir at room temperature overnight and is then filtered. The filtrate is concentrated at reduced pressure and taken up in 100 ml. of water containing 7.25 g. of L-proline and 10.58 g. of sodium bicarbonate. The mixture is stirred at 25°-35° overnight and filtered through celite. The filtrate is concentrated to remove the ethanol. Concentrated hydrochloric acid is added and the mixture is extracted several times with dichloromethane. The extracts are washed with water and dried (Na2SO4). Evaporation of the solvent yields an amber gum which is dissolved in ethylacetate. Hexane is added, causing white crystals to separate. Recrystallization from ethylacetate gives colorless needles, m.p. 177.5-179.5, labeled isomer A. The preceding compound is brominated as in Example 20 and the product reacted with potassium thioacetate in ethanol-water as in Example 21 to give the product of the Example as a glass.

1. filtrationis then filtered
2. concentrationThe filtrate is concentrated at reduced pressure
3. stirringThe mixture is stirred at 25°-35° overnight
4. filtrationfiltered through celite
5. concentrationThe filtrate is concentrated
6. customto remove the ethanol
7. additionConcentrated hydrochloric acid is added
8. extractionthe mixture is extracted several times with dichloromethane
9. washThe extracts are washed with water
10. dry with materialdried (Na2SO4)
11. customEvaporation of the solvent
12. customyields an amber gum which
13. customto separate
14. customRecrystallization from ethylacetate
15. customgives colorless needles
16. customto give the product of the Example as a glass