C[C@:2]1([O:11][C:10]([CH2:14][OH:15])([CH2:12][OH:13])[C@H:8]([OH:9])[C@H:6]([OH:7])[C@H:4]1[OH:5])O>S(=O)(=O)(O)O>[OH:13][CH2:12][C@@:10]12[CH2:14][O:15][C@@H:2]([O:11]1)[C@H:4]([OH:5])[C@@H:6]([OH:7])[C@H:8]2[OH:9]Methyl 5-C-hydroxymethyl-α-L-arabino-hexopyranose (3) (59.0 g, 0.263 moles) is dissolved in 0.70M sulfuric acid (260 ml), and stirred at 100° C. for 90 minutes. The solution is cooled to room temperature and neutralized using an ion exchange resin (Amberlite IRA-400 (OH--). The resin is filtered off, and the filtrate is refluxed for 15 minutes with activated carbon (4.0 g). Carbon is removed with a glass fiber filter, and the filtrate is evaporated to dryness with ethanol. The white waxy residue is refluxed for 15 minutes with methanol (50 ml). The solution is stored overnight at 0° C. The product is filtered to yield 20.0 g (39.6%) of 1,6-anhydro-5-C-hydroxymethyl-β-L-altropyranose (4).
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