p-Toluenesulfonic acid → HCID 131720843, compound

Participants

Reaction Steps

15.83 g of 1-benzotriazol-1-yl-N,N,N',N'-tetramethyluronium hexafluorophosphate and 9 ml of N-methylmorpholine were added to a solution of 13.65 g of Z-Asp(OBut)-OH.H2O and 15.9 g of Val-OBzl.TosOH in 250 ml of DMF. After stirring for 2 hours the reaction mixture was evaporated in a vacuum and the residue was partitioned between ethyl acetate and water. The organic phase was washed with 5% KHSO4 /10% K2SO4 solution, water, saturated NaHCO3 solution, water and saturated NaCl solution, dried over Na2SO4, filtered and evaporated. The residue was crystallized from diethyl ether/hexane and there were obtained 17.5 g of Z-Asp(OBut)-Val-OBzl of m.p. 99°; [a]D20 -27.7° (c=1, MeOH).

Provenance & Evidence