Complexes of carbohydrates with metal cations. XVI•Di-D-fructose and di-L-sorbose dianhydrides

Abstract

. 68, 1140(1 990).Di-D-fructose 2', 1:2,11-dianhydrides form complexes with metal cations if the two anomeric carbon atoms have the same configuration. Such anomers have the central 1,4-dioxane ring in a flexible form; complex formation involves 0-1, 0-1 ', 0-3, and 0-3', as confirmed by the X-ray crystal structure of the strontium complex of the P,P-dipyranose anomer. The a,p-anomers, and dianhydrides containing only furanose rings, do not form such complexes.Key words: difructose dianhydrides, complex formation with cations, crystal structure of complex, chromatographic separation on ion-exchange resins.STEPHEN JOHN ANGYAL, DONALD CHADWICK CRAIG, JACQUES DEFAYE et AND&€ GADELLE. Can. J. Chem. 68, 1140 (1990).Les 2', 1:2,11-dianhydrides du di-D-fructose forment des complexes avec les cations mCtalliques si les deux atomes de carbone anomtriques possedent la m&me configuration. Dans de tels anomeres, le cycle 1,4-dioxane central existe dans une conformation flexible; comrne il a Ct C Ctablie par diffraction des rayons-X sur le complexe de strontium de l'anomere P,P-dipyranose, la formation de complexe implique les atomes 0 -1,O-l ' , 0 -3 et 0-3'. Les anomeres a , P ainsi que les dianhydrides ne contenant que des cycles furanoses ne forment pas de tels complexes.Mots cle's : dianhydrides du difructose, formation de complexes avec les cations, structure cristalline du complexe, stparation par chromatographie sur des rCsines Cchangeuses d'ions.[Traduit par la revue] IntroductionThe reaction of D-fructose or inulin with strong aqueous acids or with anhydrous hydrogen fluoride yields a mixture of difructose dianhydrides of which nine diastereomers have been isolated and characterized (2-5). To seDarate them. chromatographic methods are emplo$ed; five of tde anhydrides have been separated from each other by reverse-phase high-performance liquid chromatography (HPLC) (6). It seemed desirable to ascertain whether chromatography on cation-exchange resins in the calcium form (7) would be suitable for their separation. In principle, this method does not seem to offer much promise because fructosides do not form strong complexes with cations (8): fructofuranosides do not complex, a-fructopyranosides form only very weak complexes at 0-4-0-5, and p-fructopyranosides weak ones at 0-4-0-5 and 0-2-0-3. However, complexing involving hydroxyl groups of both fructose moie-

Chemical and Enzymatic Approaches to Carbohydrate-Derived Spiroketals: Di-D-Fructose Dianhydrides (DFAs)

“…These characteristics can be exploited, for instance, in the preparation of surfactants, hydrophilic polymers, or complexing agents, to mention just a few. Indeed, C 2 -symmetric d -fructose-1,2’:2,1’-dianhydrides have been reported to form complexes with metal cations such as Ca 2+ and Sr 2+ [ 53 ]. A conformational study carried out by Pedersen and coworkers revealed that a boat conformation in the central 1,4-dioxane ring is predominant in these isomers due to the interplay of the anomeric effect at the spiroketal centers and the exo-anomeric effect related to the fructose moieties [ 54 ].…”

“…A conformational study carried out by Pedersen and coworkers revealed that a boat conformation in the central 1,4-dioxane ring is predominant in these isomers due to the interplay of the anomeric effect at the spiroketal centers and the exo-anomeric effect related to the fructose moieties [ 54 ]. The boat (or skew-boat) conformer is the only one detected both in the solid state and in solution for di-β- d -fructopyranose-1,2’:2,1’-dianhydride ( 14 ), for instance [ 53 ]. This arrangement allows both dioxane oxygen atoms to coordinate to a metal cation simultaneously and, at the same time, fixes a favorable orientation of the hydroxyl groups to participate in complex stabilization ( Figure 5 ).…”

Chemical and Enzymatic Approaches to Carbohydrate-Derived Spiroketals: Di-D-Fructose Dianhydrides (DFAs)

“…Furthermore, this strategy precludes the possibility of an efficient preparation of interesting DFA isomers, such as di-β-D-fructopyranose-1,2':2,1'-dianhydride (14), which are neither the kinetic nor the thermodynamic product as a consequence of stereoelectronic considerations. As commented previously, in these C 2 -symmetric derivatives, the dispirodioxane ring must adopt a boat conformation in order to comply with both, the anomeric and exoanomeric effects [53]. Such conformation, which is favourable for cation complex formation, is far higher in energy as compared with other isomeric DFAs.…”

“…A conformational study carried out by Pedersen and coworkers revealed that a boat conformation in the central 1,4-dioxane ring is predominant in these isomers due to the interplay of the anomeric effect at the spiroketal centers and the exo-anomeric effect related to the fructose moieties [54]. The boat (or skew-boat) conformer is the only one detected both in the solid state and in solution for di-β-D-fructopyranose-1,2':2,1'-dianhydride (14), for instance [53]. This arrangement allows both dioxane oxygen atoms to coordinate to a metal cation simultaneously and, at the same time, fixes a favorable orientation of the hydroxyl groups to participate in complex stabilization ( Figure 5).…”

“…This notion was first exemplified by García Fernández and Defaye [65] for the stereospecific synthesis of DFA 14 [53]. Activation of 2,3:4,5-di-Oisopropylidene-β-D-fructopyranose (20), readily accessible in one step from commercial D-fructose [66], with anhydrous HF resulted in the rearrangement of the anomeric isopropylidene group, with simultaneous formation of a reactive β-fructopyranosyl fluoride (21).…”