How to Synthesize Ribose

A practical, four-step method can synthesize ribose from an L-arabinose derivative using primarily the Swern oxidation technique and a subsequent stereoselective reduction along with inversion of the 2-hydroxy group of the L-arabinose derivative. According to J Stage, if the process is carried out correctly, the results of this particular method can demonstrate a relatively high 76.3 percent yield from protected L-arabinose derivatives, which marks a significant increase in experimental efficiency.

Things You'll Need

• L-arabinose
• 16.4 g, 100 millimolar methyl beta-L-arabinopyranoside
• 38.6 g, 300 millimolar 2,2-dimethoxypropane
• 130 milliliters of dry dimethyl formamide
• Amberlyst 15, 1 g
• Mechanical stirrer
• Dimethyl sulfoxide (DMSO)
• Oxalyl chloride
• Reducing agent such as LiAlH4
• EtOH
• 80 percent AcOH
• Methyl beta-L-ribopyranoside
• Silica gel column chromatography apparatus
• Beaker
• Bunsen burner

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Instructions

• 1

  Create a sufficiently pure, colorless syrup of the L-arabinose derivative 3,4-O-isopropylidene-beta-L-arabinoside, from L-arabinose. This is achieved by mixing 16.4 g, 100 millimolar methyl beta-L-arabinopyranoside with 38.6 g, 300 millimolar 2,2-dimethoxypropane in 130 milliliters of dry dimethyl formamide in the presence of Amberlyst 15, 1 g. This needs mechanical stirring at room temperature for 18 hours. Filter the resin and evaporate the solvent, then co-evaporate the residue produced with m-xylene. The product is L-arabinose in syrup-like form.

• 2

  Subject the L-arabinose derivative to Swern oxidation. This is a standard chemical procedure which avoids the use of toxic metals, as explained by Organic Chemistry. Dimethylchlorosulphonium ion is created by reacting DMSO with oxalyl chloride at -78 degrees Celsius. This intermediate is then de-protonated to form a sulphur ylide, which is then intramolecularly de-protonated to yield the product.

• 3

  Follow with reduction in the presence of an effective reducing agent, such as LiAlH4 or LiAlH(OtBu)3, in EtOH at zero degrees Celsius.

• 4

  De-protect the isopropylidene group of the derivative (which may not have separated off yet) by adding the compound to 80 percent AcOH, methyl beta-L-ribopyranoside and shake off the excess, unwanted groups by subjecting the resulting mixture to silica gel column chromatography.

• 5

  Repeat the Swern oxidation, reduction and de-protection with the resulting mixture, to further improve the mid-stage yield, then de-protect the anomeric position of the final compound by treating it with 0.8 molar HCl.

• 6

  Neutralize the reaction mixture with an acid catalyst such as the Dowex 50w cation exchange resin in hydrogen ion (H+) form to create the final, required product, L-ribose.