a method of preparing a ribofuranose derivative essentially free of pyranose compounds includes a step of contacting a solution of mdr containing mdrp as an impurity in a solvent including methanol and / or tetrahydrofuran with at least one alkali metal periodate under conditions sufficient to oxidize at least a portion of the mdrp . mdr containing at most 5 wt % of mdrp based on the total weight of mdr and mdrp may be produced .