Ethylmorpholine → H-Val-Val-OBut.HCl

Participants

Reaction Conditions

Reaction Steps

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).

Provenance & Evidence