反应详情

3-Hexadecanoyloxyoctadecanoic acid (10.8 g) prepared by the method described in Preparation A-2 (5) and N-hydroxysuccinimide (2.3 g) was dissolved in dioxane (60 ml). N,N'-Dicyclohexylcarbodiimide (4.2 g) was added thereto under ice cooling. The mixture was stirred at ambient temperature over-night. The crystallized N,N'-dicyclohexylurea was filtered off and the filtrate was concentrated to give a residue. The residue was dissolved in N,N-dimethylformamide (70 ml). To this solution was added a solution of L-valine (5.85 g) and triethylamine (6.95 ml) in water (50 ml) at 0° C. The resulting mixture was stirred at ambient temperature overnight. The reaction mixture was acidified with 1N hydrochloric acid, extracted with ethyl acetate, washed with water and dried over magnesium sulfate. Ethyl acetate was distilled off to give a residue which was crystallized from petroleum ether to give crystals of N-(3-hexadecanoyloxyoctadecanoyl)-L-valine (8 g).

1. filtrationThe crystallized N,N'-dicyclohexylurea was filtered off
2. concentrationthe filtrate was concentrated
3. customto give a residue
4. stirringThe resulting mixture was stirred at ambient temperature overnight
5. extractionextracted with ethyl acetate
6. washwashed with water
7. dry with materialdried over magnesium sulfate
8. distillationEthyl acetate was distilled off
9. customto give a residue which
10. customwas crystallized from petroleum ether