Pentafluorophenyl esters for temporary carboxyl group protection in solid phase synthesis of N-linked glycopeptides.

Abstract

The compound Ac 3GlcNAcβ1-NH-Fmoc ( 3) was synthesized and transformed into the β-glucosyl amine ( 1) which was subsequently acylated with Fmoc-Asp(Cl)-O-Pfp ( 5) prepared from the readily available Fmoc-Asp(O-tBu)-O-Pfp ( 4). The resulting Fmoc-Asn(Ac 3GlcNAcβ1-N-)-O-Pfp ( 6) was used as a building block in the solid phase synthesis of an 11 residue glycopeptide fragment of the enzyme glucoamylase (AMG).