Boc-L-Pro-D-Ala-L-His(Bom)-D-Ala-OBzl

Boc-L-Pro-D-Ala-L-Lys(Z)-D-Ala-OBzl

Boc-L-Pro-D-Ala-L-Arg(Tos)-D-Ala-OBzl