Trifluoroacetic acid → Trifluoroacetic acid

Participants

Reaction Steps

To a solution of 322 mg (0.681 mmol) of Boc-Cha-Phe(3-tBu)-NH2 in 2 ml of methylene chloride, 1 ml of TFA was added and the mixture was stirred at room temperature for 2 hours. The solvent was distilled off under reduced pressure to give a TFA salt of Cha-Phe(3-tBu)-NH2; to a solution of the TFA salt in 2 ml of DMF, 0.1 ml of TEA, 343 mg (0.817 mmol) of Z-Phe-ONp and 125 mg (1.02 mmol) of DMAP were added and the mixture was stirred at room temperature for 3 hours. The reaction mixture was diluted with ethyl acetate and washed first with saturated aqueous NaHCO3, then with water and finally with saturated brine. The organic layer was dried with anhydrous magnesium sulfate and concentrated under reduced pressure; the resulting residue was subjected to silica gel column chromatography (eluting solvent; chloroform:methanol=10:1) to give Z-Phe-Cha-Phe(3-tBu)-NH2 in the amount of 192 mg (43%).

Provenance & Evidence