Solid-Phase Stereocontrolled Synthesis of Oligomeric P-Modified Glycosyl Phosphate Derivatives Using the Oxazaphospholidine Method.

Glycosyl phosphate repeating units can be found in the glycoconjugates of some bacteria and protozoa parasites. These structures and their P-modified analogs are attractive synthetic targets as antimicrobial, antiparasitic, and vaccine agents. However, P-modified glycosyl phosphates exist in different diastereomeric forms due to the chiral phosphorus atoms, whose configuration would highly affect their physiochemical and biochemical properties. In this study, a stereocontrolled method was developed for the synthesis of P-modified glycosyl phosphate repeating units derived from the lipophosphoglycan of Leishmania using the oxazaphospholidine approach. The solid-phase synthesis facilitated the elongation and purification of the glycosyl phosphate derivatives, while two P-modified glycosyl phosphates (boranophosphate and phosphorothioate) were successfully synthesized with up to three repeating units.

Solid-Phase Synthesis of Fluorinated Analogues of Glycosyl 1-Phosphate Repeating Structures from Leishmania using the Phosphoramidite Method.

Bacterial and protozoan sugar chains contain glycosyl 1-phosphate repeating structures; these repeating structures have been studied for vaccine development. The fluorinated analogues of [ß-Gal-(1→4)-α-Man-(1→6)-P-] n , which are glycosyl 1-phosphate repeating structures found in Leishmania, were synthesised using the solid-phase phosphoramidite method. This method has been less extensively studied for the synthesis of glycosyl 1-phosphate units than H-phosphonate chemistry. A stepwise synthesis of a compound containing five such repeating units has been conducted using the phosphoramidite method herein, which is the longest glycosyl 1-phosphate structures to be chemically constructed in a stepwise manner.

Stereoselective synthesis of P-modified α-glycosyl phosphates by the oxazaphospholidine approach.

α-Glycosyl phosphate derivatives are widely known as constituents of biomolecules. To date, several types of non-natural α-glycosyl phosphates including "P-modified analogs" have been synthesized to investigate their characteristics. Herein a new approach to the stereoselective modification of the intersugar phosphorus atom in α-glycosyl phosphates by use of the oxazaphospholidine method is presented. Via this approach, the dimers of α-glycosyl phosphorothioates and α-glycosyl boranophosphates were obtained efficiently and stereoselectively.