HCID 15600423, compound → HCID 54240983, compound

Participants

Reaction Steps

A mixture of benzyloxycarbonyl-glycyl-phenylalanyl-phenylalanine methyl ester (1.5 g, 2.9 mmoles described in Example 1) and 5% palladium on carbon (0.15 g) in acetic acid 140 ml) is rapidly stirred under an atmosphere of hydrogen until the benzyloxycarbonyl group is removed. The mixture is filtered and the filtrate is evaporated. The residue is triturated with ether to give a precipitate of glycyl-phenylalanyl-phenylalanine methyl ester. A solution of benzyloxycarbonly-(N6 -t-butoxycarbonyl)-lysine p-nitrophenyl ester [1.36 g, 2.7 mmoles, described by E. Sandrin and R. A. Boissonas, Helv. Chem. Acta. 46, 1637 (1963)] in dimethylformamide (20 ml) is added dropwise to a cooled solution of the above compound (1.2 g, 217 mmoles) and N-ethylmorpholine (1.35 ml, 2.7 mmoles). The reaction mixture is stirred overnight at room temperature and evaporated. The residue is dissolved in methanol (4 ml) and diethyl ether is added. The precipitate is crystallized from ethyl acetate-petroleum ether (30°-60° C.) to obtain the title compound, mp 139°-142° C.

Provenance & Evidence