Glucosamine disaccharide

These data unequivocally prove that the D-glucosamine disaccharide isolated from Salmonella lipid A contains a B(1— 6) linkage. In earlier studies, Gmeiner e t til., using a different approach, had also come to the conclusion that, in Salmonella lipid A, a B(1— 6)-linked D-glucosamine disaccharide was present... 

The PhEur 2005 describes sodium hyaluronate as the sodium salt of hyaluronic acid, a glycosaminoglycan consisting of D-glucuronic acid and N-acetyl-o-glucosamine disaccharide imits. 

Two further degradation products have been obtained from moenomycin A, suggesting that when the part structures (42) and (43), are linked together they form the complete antibiotic. Another report describes the glucose-glucosamine disaccharide present in fragment (42), which was obtained from moenomycin A by acid hydrolysis. Earlier work on the structure and properties of moenomycin A has been reviewed. ... 

Figure 1. Chemical structure of HA D-glucuronic acid-P(1,3)-N-acetyl-D-glucosamine disaccharide units linked through P(l,4) glycosidic bonds (Deschrevel, in press).

Figure 1. Chemical structures of lipid A-diphosphate (A) and two antagonistic lipid A-diphosphate molecules, (B and C). Lipid A-diphosphate from E. coli is a 1,4-di-phosphorylated P-1,6-linked D-glucosamine disaccharide with four residues of amide-and esterified R-(-)-3-hydroxy fatty acids ( denotes the chiral centers in the hydroxy fatty-acid esters, apart form the chiral and epimeric carbons in the disaccharide moieties which are not marked). The antagonistic lipid A-diphosphate molecules shown in (B) and (C) contain the same disaccharide as in (A) however, they differ in the number anchored carbohydrate positions and the number of chiral fatty-acid chains but the chain lengths is the same (C J. The corresponding monophosphate of lipid A is only phosphorylated at the reducing end of the disaccharide.

Three members of the set of glucosamine disaccharides (115) were made for use in the total synthesis of lipid A of Proteus mirabilis (116). The compound (115, R =a-allyl, R =Cl3CCH2C02, R =Cl3C(Me)2C02) was most efficiently for the synthesis. ... 

---