Synthesis and NMR studies of cyclopeptides containing a sugar amino acid

(Matrix presented) R² = H, Me, Bn or aminobutyl Cyclopeptides containing Glucuronic acid methylamine (Gum) alternating with Gly, L-Ala, D-Ala, L-Phe, D-Phe, L-Lys, or D-Lys were synthesized by a combination of solid-phase synthesis and solution chemistry. A more effective pathway to synthesize the sugar amino acid Gum in higher yields and in a shorter period of time was developed. Gum is employed in the benzylated and deprotected form. The cyclopeptides were characterized by NMR and the structure of one deprotected cyclic peptide solved.