Water → Boc-D-Tyr(Me)-L-Ile-D-Pro-OBzl

Participants

Reaction Steps

While cooling on ice, TFA (5 mL) was added to Boc-L-Ile-D-Pro-OBzl (1.63 g, 3.38 mmol), and this was left to stand for 30 minutes. TFA was removed by evaporation, and the residue was dried under reduced pressure. This was dissolved in DMF (8 mL), Boc-D-Tyr(Me)-OH (1.50 g, 5.07 mmol) was added, and while cooling on ice, HOBt.H2O (518 mg, 3.38 mmol), HBTU (1.92 g, 5.07 mmol), and Et3N (2.37 ml, 16.9 mmol) were added, and this mixture was stirred for 3 hours. The reaction solution was concentrated, extracted with ethyl acetate, the extract was washed 3 times each with 10% aqueous citric acid solution, 4% aqueous sodium bicarbonate solution, and saturated bee, and dried over magnesium sulfate, and then ethyl acetate was removed by evaporation. Purification by silica gel chromatography yielded the desired product as a foam (column: Merck Kieselgel 60 Φ 3.4×30 cm, eluent: CHCl3/MeOH, 99/1). TLC: Rf, 0.89 (CHCl3/MeOH, 9/1). Yield: 1.44 g (2.42 mmol, 72%).

Provenance & Evidence