Synthesis and structure of N-ferrocenylglycosylamines; redox chemistry of O-ferrocenylglycosides and N-ferrocenylglycosylamines

The N-ferrocenylamine-carbohydrate conjugates N,N-bis(ferrocenylmethyl)-N-(2,3,4,6-tetra-O-acetyl-1-deoxy-beta-D-glucopyranosyl)amine, N-(2,3,4,6-tetra-O-acetyl-1-deoxy-beta-D-glucopyranosyl)aminomethylferrocene and N,N-bis(ferrocenylmethyl)-N-[4-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)-2,3,6-tri-O-acetyl-1-deoxy-beta-D-glucopyranosyl]amine have been synthesized from FcCH(2)NMe(3)(+)I(-) and the appropriate aminosugars. Deprotection using an ion exchange resin gave the analogous water soluble complexes. A short C-N bond at the anomeric carbon in the crystal structure of the first compound is attributed to an exo-anomeric n-sigma* interaction between the exo C-N and endo C-O bonds. N-Ferrocenylmethylalkanolamines FcCH(2)NH(CH2)(n)OH and (FcCH(2))(2)N(CH2)(n)OH (n = 2 or 5) were synthesized in good yield using reductive amination reactions. Owing to the basicity of the N-ferrocenylamine component the electrochemistry is both solvent and pH dependent; protonation occurs in polar solvents and in all solvents with the first two compounds. Rapid oxidation to the non-protonated ferrocenium complexes occurs in aqueous solvents under physiological pH.