反应详情

To a suspension of L-arabinose (100 g, 667 mmol) in anhydrous MeOH (450 mL) was added a HCl/MeOH solution (7.3 g dry HCl in 50 mL MeOH) at room temperature under argon atmosphere. The mixture was refluxed for 2 h and cooled down to room temperature. The solution was concentrated to about ¾ of its volume to give a suspension. The solid precipitated was filtered and washed with cold MeOH (20 mL) to give the first crop as a crystalline powder (35.23 g). The filtrate was concentrated (35° C.) to ¼ of its volume. The solid precipitated was filtered, washed and dried as above to give the second crop (9.66 g) as a colorless crystalline powder. The concentration and filtration were repeated to afford additional 28.31 g of the product (total 73.2 g, 67%). 1H NMR (D2O) δ3.30 (s, OCH3, 3H), 3.56 (dd, 1H, H5), 3.73 (m, 1H, H4), 3.77 (dd, 1H, H5), 3.82 (bs, 1H, H2), 4.73 (m, 1H, H1).

1. temperatureThe mixture was refluxed for 2 h
2. concentrationThe solution was concentrated to about ¾ of its volume
3. customto give a suspension
4. customThe solid precipitated
5. filtrationwas filtered
6. washwashed with cold MeOH (20 mL)