Metal chelation by the common 2-amino-2-deoxy-, 2-N-acetylamino-2-deoxy-, and 2-deoxy-hexoses.
The chelating properties of the common aldohexoses d-glucose, d-mannose, and d-galactose are characteristically modified in 2-substituted derivatives. The 2-amino-2-deoxy-aldohexoses provide mono- and bis-metallisable anionic ligands after their reaction with metal probes of the Pd(II)N(2) type (N(2) = bidentate nitrogen ligand). The 2-amino function reliably participates in metal binding of the, mostly pyranoidic, carbohydrate chelators. Acetylation of the amino function yields the biologically important 2-N-acetylamino-2-deoxy-hexoses (GlcNAc, ManNAc, and GalNAc). On reaction with the palladium probe, the metal-binding properties of the deprotonated acetylamino function depends on the steric requirements introduced by the acetyl residue which is forced into a coplanar arrangement with the chelate ring. In the two 2-deoxy-aldohexoses, 2-deoxy-arabino-d-hexose (the 2-deoxy derivative of both d-glucose and d-mannose, '2-deoxy-glucose') and 2-deoxy-lyxo-d-hexose ('2-deoxy galactose'), the 2-position cannot contribute to metal binding. As a result, furanose-1,3 chelation becomes an important metal-binding mode. Due to the decreased acidity of the 2-deoxy-glycose's 1-hydroxy function, monometallation also takes place at the pyranose's 3,4-site.
Schwarz
Thomas
T
Department of Chemistry of the Ludwig Maximilian University Munich, Butenandtstr. 5-13, D-81377, Munich, Germany.
Hess
David
D
Klüfers
Peter
P
D002614:Chelating Agents / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005688:Galactosamine / Q000737:chemistry*; D005944:Glucosamine / Q000737:chemistry*; D006595:Hexosamines / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D010165:Palladium / Q000737:chemistry*
D002614:Chelating Agents; D006595:Hexosamines; C008322:mannosamine; D010165:Palladium; D005688:Galactosamine; D005944:Glucosamine