Solid-Phase Synthesis of Phosphonylated Peptides

We report the solid-phase syntheses of two series of phosphonylated peptides using Fmoc-protected amino acids. The peptides corresponded to regions containing phosphonylated Ser195 in the active site of butyrylcholinesterase and Tyr411 of ­human serum albumin. The phosphonylated Fmoc-protected amino acids were used in solid-phase peptide synthesis to prepare the peptides. Fmoc-serine and Fmoc-tyrosine with benzyl ester protection were treated with alkyl methylphosphonic monochloridates to phosphonylate the side-chain hydroxy groups. The phosphonylated peptides were designed to mimic the protein region after exposure of the proteins to organophosphorus agents.