反应详情

30 g (291 mmol) of methyl D,L-alaninate hydrochloride and 64.77 g (640 mmol) of triethylamine are initially charged in 300 ml of dry methylene chloride, at 0° C. 43.24 g (291 mmol) of heptanoyl chloride in 50 ml of methylene chloride are added dropwise. The mixture is allowed to warm to room temperature and stirred at this temperature for 2 h. The precipitate is filtered off, and the methylene chloride phase is extracted with saturated sodium bicarbonate solution and with saturated sodium chloride solution and dried over sodium sulphate. The solvent is removed under reduced pressure and the residue is dissolved in 300 ml of methanol. 300 ml of water, in which 46.55 g (1164 mmol) of sodium hydroxide are dissolved, is added to this solution, and the mixture is stirred at RT for 2 h. The mixture is filtered, the methanol is removed using a rotary evaporator and the aqueous phase that remains is acidified with conc. Hcl to pH 1-2. The precipitated product is filtered off and dried. A second product fraction is obtained by extracting the aqueous phase with ethyl acetate.

1. filtrationThe precipitate is filtered off
2. extractionthe methylene chloride phase is extracted with saturated sodium bicarbonate solution and with saturated sodium chloride solution
3. dry with materialdried over sodium sulphate
4. customThe solvent is removed under reduced pressure
5. dissolutionthe residue is dissolved in 300 ml of methanol
6. additionis added to this solution
7. stirringthe mixture is stirred at RT for 2 h
8. filtrationThe mixture is filtered
9. customthe methanol is removed
10. customa rotary evaporator
11. filtrationThe precipitated product is filtered off
12. customdried
13. customA second product fraction is obtained
14. extractionby extracting the aqueous phase with ethyl acetate