Carbohydrates tagged with the CCo3(CO)9 cluster †

Fluorescent Sugar and Uridine Conjugates of 1,8-Naphthalimides with Methyl and Ferrocenyl Headgroups

“…26 protons similar to those found when a Co 3 cluster was linked by OCH 2 to the anomeric carbon. [27] The strong electronacceptor influence of the naphthalimide is also seen in the potential of 0.79 V for E • [8] +/0 ; this potential is 120 mV anodic of E • [5] +/0 . The route to 6 in Scheme 4 offered a strategy for the synthesis of naphthalimide conjugates of the well-known antiviral agent 5-iododeoxyuridine (5-I-dU).…”

“…X-Ray quality crystals were only obtained from 4 and 6 as 5, 7, and 8 were oils, in common with other µ-alkyne Co 2 (CO) 6 sugar complexes. [27] The X-ray structures of 4 and 6 are discussed below.…”

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

“…However, in 50% aqueous methanol E 1/2 for 3 is also 0.49 V; the importance of using a solvent-insensitive reference is well illustrated by this system as E 1/2 for 3 is 0.47 and 0.26 V against SCE in dichloromethane and aqueous methanol respectively. A solvent shift of 50 mV from dichloromethane to aqueous methanol was also noted with (OC) 9 Co 3 C-carbohydrate complexes 3 indicating that the generic solvent interaction is with the carbohydrate portion of the molecule rather than with the ferrocenyl couple. Surprisingly, the electrode response was different for compounds 4 and 5 where there are two ferrocenyl redox centres.…”

“…A useful diagnostic was δ C for the anomeric carbon which is in the range 88.7-91.9 for N-1glycosylamines and 92.4-101.2 for O-glycosides. 3 Complexes 3-7 are soluble in organic solvents except hydrocarbons whereas the deprotected analogues 8-11 are soluble in chlorinated solvents, acetone, alcohols and water. Compound 9, the least water-soluble of the deprotected glycosides, has a solubility of 1.8 g l Ϫ1 in water.…”

“…In addition, these conjugates can be used selectively to target specific sites and functions 2 and to label polysaccharides with heavy atoms. 3 The accompanying paper 1 describes the background literature for compounds where a ferrocene moiety is linked to a sugar via a heteroatom and successful synthetic strategies for the preparation of N-glycosyloxy-N-(hydroxyalkyl)aminomethylferrocenes. In an extension of this theme we wished to determine if a ferrocenylamine unit N-bound to the sugar via the anomeric carbon experienced a perturbation of its electronic properties and if steric perturbations of the carbohydrate occur with the proximity of a metallocene.…”