Abstractα‐Alkoxycarbonyl protected ornithines were treated withN,N′‐[Z(2Cl)]2‐S‐methylisothiourea andN,N′‐[Z(2Br)]2‐S‐methylisothiourea,N,N′‐Z2‐S‐methylisothiourea andN,N′‐Boc2‐S‐methylisothiourea to formNα, ω, ω′‐tris‐alkoxycarbonyl arginines. Two of them, Boc‐Arg‐{ω,ω′‐[Z(2Br)]2}‐OH and Boc‐Arg‐{ω,ω′‐[Z(2Cl)]2}‐OH, were used for the synthesis of dermorphin fragments containing two or three arginine residues. Examination of the products by HPLC and ESI‐MS revealed that the purity of the materials obtained with the use of the new derivatives was higher than that obtained in concurrent syntheses in which Boc‐Arg(Tos) was u