Sucrose, maltose, and lactose are important disaccharides and cheap and valuable sources of renewable materials for industrial applications.1) For example, sucrose can be converted to ethanol, 2) which is widely used in various fields of industry and the source of C1 chemistry. Recently, natural disaccharides and trisaccharides have attracted enormous attention. 3,4) A large number of oligosaccharides have been conjugated for new DNA-binding antitumor agents, 3) and specific ligands for cell-surface recognition 4) have been produced by chemical and enzymatic syntheses.We demonstrated that the reaction of D-glucose with cyclotriphosphate (P 3m ) afforded b-D-glucopyranosyl 1-triphosphate in good yield in a one-step process without protection of hydroxyl groups.5,6) Although D-glucose exists as an equilibrium mixture of a and b anomers under the reaction conditions, only b-D-glucopyranosyl 1-triphosphate was obtained stereoselectively. This method would be applicable to the phosphorylation of other monosaccharides. 7,8) The phosphorylated products of oligo-and polysaccharides are expected to act as chiral selectors, 9) masking agents of metal ions, 10) and material for drug delivery systems (DDS). 11) Although this stereoselective phosphorylation is effective for monosaccharides, the existence of 1-OH is essential, which is not feasible in polysaccharides. It is more significant to apply this stereoselective phosphorylation reaction to disaccharides to open the way for the phoshorylation of oligo-and polysaccharides.In the present study, the reaction of cellobiose (1), lactose (2), maltose (3), sucrose (4), and a,a-trehalose (5) with P 3m was studied to develop selective phosphorylation of disaccharides in aqueous solution.
Results and DiscussionPhosphorylation of Cellobiose (1), Lactose (2), and Maltose (3) with P 3m Reducing disaccharides used in the present study are shown in Chart 1. Phosphorylation was carried out essentially according to the previous method.6) Figure 1 shows the HPLC profiles for the reaction solution of cellobiose (1) (1.0 mol · dm Ϫ3) and P 3m (0.5 mol · dm
Ϫ3) incubated at pH 12 at room temperature. The peak of the main product (6) appeared at a retention time of about 17 min. The yield of 6 increased with reaction time to reach the maximum yield of 28% after 78 h and then decreased gradually (Fig. 2).To identify product (6) in the phosphorylation of 1 with P 3m , 6 was isolated using anion-exchange resin (see Experimental). (Table 1) of 6 show two doublets (Ϫ11.8, Ϫ5.51 ppm) and one doublet of doublets (Ϫ20.6 ppm) characteristic of triphosphate derivatives. [6][7][8]12) Figure 3A shows the 31 P-NMR spectrum of the P a region in 6. The spectrum had one doublet of doublets at Ϫ11.8 ppm, which became a doublet on 1 H-decoupling, indicating the characteristic peak of P a in triphosphate deriva-
November 2002Chem. Pharm. Bull. 50(11) 1453-1459 (2002) 1453 * To whom correspondence should be addressed. e-mail: mtsuhako@kobepharma-u.ac.jp © 2002 Pharmaceutical Society of Japan
Phosphorylation...