Synthesis of tetrasaccharide containing glycopeptides related to bacterial cell wall starting from free tetrasaccharide by the pentafluorophenyl ester method

Abstract

The free tetrasaccharide GlcNAc-MurNAc-GlcNAc-MurNAc was converted into the tetrasaccharide bis-pentafluorophenyl ester I by treatment with bis(pentafluorophenyl)carbonate. Reaction of I with suitably protected peptides afforded [GlcNAc-MurNAc-L-Ala-D-Glu(OBzl)2]2 (II) and [GlcNAc-MurNAc-L-Ala-D-iGln-L-Lys(Z)-OBzl]2 (IV). Catalytic hydrogenolysis of compound II and IV yielded (GlcNAc-MurNAc-L-Ala-D-Glu)2 (III) and (GlcNAc-MurNAc-L-Ala-D-iGln-L-Lys)2 (V), respectively. [GlcNAc-MurNAc-L-Ala-D-iGln-L-Lys(St)2]2 (VI) was prepared from compound V by reaction with stearic acid N-hydroxysuccinimide ester.