Fmoc-protected, glycosylated asparagines potentially useful as reagents in the solid-phase synthesis of N-glycopeptides.

1-Amino 1-deoxy derivatives of unprotected O-beta-D-galactopyranosyl-(1-->3)-2-acetamido-2-deoxy-beta-D-glucopyrano se, 2-acetamido-2-deoxy-D-galactose, D-galactose, lactose, D-fucose, D-mannose, and 2-deoxy-D-arabino-hexose were prepared and acylated with N-fluorenylmethoxycarbonylaspartic acid alpha-tert-butyl ester. The anomeric configuration of the N-glycosyl bond (including that of the mannose derivative) in each of the purified compounds was shown to be beta. The probable stability of the N-glycosyl and glycosidic bonds during the conditions of solid-phase peptide synthesis was investigated by treatment of the glycosylated asparagine derivatives with different concentrations of trifluoroacetic acid. Based on their stability, we found that Fmoc-Asn(sugar)-OH derivatives are excellent candidates for automated synthesis of biologically active glycopeptides.