Synthesis of α-d-Glucose 1,6-Diphosphate, α-d-Mannose 1,6-Diphosphate, α-d-Ribose 1,5-Diphosphate, and N-Acetyl-α-d-glucosamine 1,6-Diphosphate

A simple general procedure for the synthesis of terminally phosphorylated α anomeric diphosphate derivatives of d-glucose, d-mannose, d-ribose, d-galactose, d-glucosamine, and N-acetyl-d-glucosamine was developed. The fully acetylated sugar 6-phosphates, 5-phosphate in the case of d-ribose, were phosphorylated at the anomeric carbon atom by condensation with crystalline phosphoric acid. The O-acetyl groups in the resulting diphosphate derivative were removed by treatment with alkali, and excess phosphoric acid was precipitated as an insoluble lithium salt. The sugar diphosphates were isolated by ion exchange chromatography and the lithium, potassium, and barium salts of each of these compounds were prepared and characterized. In each case, the ratio of acid-labile phosphate to total phosphate to acid-labile reducing sugar in the final product was 1:2:1. The compounds migrated as diphosphate esters on electrophoresis and paper chromatography. The final product was completely homogenous with respect to the sugar component. The structure and ring configuration were determined by analysis and periodate oxidation. The α configuration of the phosphate group at the anomeric carbon was established by comparing the optical rotation of the dialdehyde diphosphate derivative formed on periodate oxidation with the optical rotation of the product formed upon oxidation of α-d-glucose 1,6-diphosphate. The products were all active when they were assayed for enzymatic activity with phosphoglucomutase.