p-Toluenesulfonic acid → HCID 131717379, compound

Participants

Reaction Steps

To a solution of Leu-OBzl.p-TsOH(2.06 g), Boc-DVal (1.09 g), HOBT.H2O(0.80 g) and N-methylmorpholine(0.55 ml) in dichloromethane(10 ml) was added EDCI HCl(1.01 g) under ice cooling. The resulting mixture was stirred at room temperature for 5 h. Saturated NaHCO3 (10ml) was added, and the mixture was extracted with dichloromethane(50 ml×3). The combined organic layers were dried over MgSO4 and filtered. The solvent was evaporated under reduced pressure. The residue was purified by dry column flash chromatography on silica gel(Merck, KIESELGEL 60) with hexane/EtOAc(2/1) for elution to give Boc-nVal-Leu-OBzl(2.03 g) as a colorless powder. The dipeptide(1.47 g) was added by portions to TFA(3.5 ml) under ice cooling. The mixture was stirred under ice cooling for 30 min and concentrated in vacuo. To the residue was added saturated NaHCO3 (10 ml) and the mixture was extracted with dichloromethane(50 ml×3).

Provenance & Evidence