An Efficient Method for The Preparation of w, w′-bis-Urethane Protected Arginine Derivatives

Abstract

Fmoc-Arg^{w, w′}(Boc)₂-OH and Boc-Arg^{w, w′}(Cbz)₂-OH were prepared in two steps: Guanylation of Cu(II)-ornithine complex at N^δ with N, N′bis-urethane protected derivatives of 1-guanylpyrazole, followed by N^α-protection using either 9-fluorenylmethyl succinimidylcarbonate or di-t-butyl-dicarbonate in the presence of EDTA. The overall yields of these products (2 steps) were 65% and 73%.