反应详情

温度

0 °C

37.7 g of Z-Val-OH, 31.4 g of H-Val-OBut.HCl and 19.75 g of HOBt are dissolved in 200 ml of dimethylformamide. 19.5 ml of N-ethylmorpholine are added to the solution, followed by 33 g of DCC at 0° C. The mixture is stirred for 1 hour at 0° C. and for 1 hour at room temperature, the precipitate is filtered off and the filtrate is concentrated in vacuo. The residue is partitioned between 200 ml of ethyl acetate and 200 ml of water. The ethyl acetate phase is then extracted by shaking with 150 ml of saturated NaHCO3 solution, 150 ml of K2SO2 /KHSO4 solution, 150 ml of saturated NaHCO3 solution and 150 ml of water and is dried over Na2SO4 and concentrated. The resulting oil (60 g) is dissolved in 300 ml of methanol and subjected to catalytic hydrogenation at pH 4.5 after adding methanolic hydrochloric acid and Pd-on-BaSO4. When the reaction is complete the catalyst is filtered off and filtrate is concentrated. The residue crystallizes from ether. Yield 40 g. Melting point 191°-194°, [α]D23 =-8.3° (c=1, in methanol).

1. filtrationthe precipitate is filtered off
2. concentrationthe filtrate is concentrated in vacuo
3. customThe residue is partitioned between 200 ml of ethyl acetate and 200 ml of water
4. extractionThe ethyl acetate phase is then extracted
5. stirringby shaking with 150 ml of saturated NaHCO3 solution, 150 ml of K2SO2 /KHSO4 solution, 150 ml of saturated NaHCO3 solution and 150 ml of water
6. dry with materialis dried over Na2SO4
7. concentrationconcentrated
8. dissolutionThe resulting oil (60 g) is dissolved in 300 ml of methanol
9. additionafter adding methanolic hydrochloric acid and Pd-on-BaSO4
10. filtrationis filtered off
11. concentrationfiltrate is concentrated
12. customThe residue crystallizes from ether
13. customMelting point 191°-194°, [α]D23 =-8.3° (c=1, in methanol)