CONFORMATIONAL STUDY OF SYNTHETIC DELTA(4)-URONATE MONOSACCHARIDES AND GLYCOSAMINOGLYCAN-DERIVED DISACCHARIDES

Sixteen Delta(4)-uronate monosaccharides were chemically synthesized. Their carboxy group was protected as a methyl or benzyl ester, the ano meric hydroxyl group as a benzyl glycoside and the 2 and 3 hydroxyl gr oups were protected with different substitution patterns as both ester and ether derivatives. Disaccharides containing Delta(4)-uronates wer e prepared from heparin using heparin lyases. Their carboxy group was unprotected or protected as a benzyl ester and the two hydroxyls in th e uronate moiety were free, as O-sulfo derivatives or acylated. The co nformation of these unsaturated uronate monosaccharide and disaccharid e residues was studied using H-1 NMR by examining interproton vicinal coupling constants. The Delta(4)-uronate residue adopted either the H- 2(1) or the H-1(2) conformations. The equilibrium between these two co nformers was shown to be controlled by substitution pattern. (C) 1998 Elsevier Science Ltd. All rights reserved.