D-glucoronic acid

Another important glucosaminoglycan of the ECM in cormective tissues, especially cartilage and skin, is hyaluronic acid. It consists of repeating disaccharide units of d glucoronic acid and D-A-acetyl-glucosamine. For biomedical applications. 

In an elegant synthesis of KDG (3-deoxy-D-glucoronic acid), DAH and KDO, the reagent 93 was shown as a very useful [93]. The synthesis proceeded through 5-ylidene-l,4-dioxalan-4-one intermediate. In the case of KDO it was formed from the protected mannose-derived aldehyde 98 and ylide 93, generated from its phosphonium bromide (Scheme 22). 

Another metabolite isolated from the specie, Pseudopterogorgia americana, is corallan, 39, the chemistry of which was investigated by Molchanova and coworkers [29], Corallan, 39, a sulphated glycoprotein contains D-glucose, D- and L-galactoses, D-arabinose, L-flicose and D-glucoronic acid. Some structural features of the polysaccharide moiety of 39 are shown in scheme 3. 

The main building blocks are D-glucose, D-mannose, D-galactose, D-xylose and L-arabinose, and L-rhamnose as well as L-fucose as deoxyhexoses and 4-O-methyl-D-glucoronic acid, D-galacturonic acid and D-glucuronic acid complete the diverse monomer fraction. Up to a maximum of 200 monomer-units—in form of pyranose structures in both a- and (3-form—are linked to form, in comparison to mechanically and chemically less stable cellulose polymers. 

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