反应详情

To a solution of 3,4-di-O-acetyl-L-rhamnal (5.0 g) and lithium bromide hydrate (5.0 g) in acetonitrile (150 ml), activated resin prepared as in Example 1 (3.0 g) and water (6 ml) were added and stirred at room temperature for 15 min. The product was isolated as described for Example 1. Purification by chromatography on a column of Silica Gel using ethyl acetate-hexane 3:8) as eluant gave the title compound (3.75 g). α:β=2:1. [α]D20 =-96.8°±2° (c 0 96. CHCl3). 1H NMR δ: 5.36 (H-1α), 5.33 (m, H-3α), 4.98 (m, H-3β), 4.90 (dd, H-1β), 4.75 (t, H-4), 4.12 (m, H-5α), 3.54 (m, H-5β), 2.39 and 2.26 (m, H-2eq), 1.77 and 1.66 (m, H-2ax), 1.23 and 1.17 (d, CH3). MS (calc. mass=232). Obs. m/e 231.13, 215.12, 155.09 (100 %).

1. additionwere added
2. customThe product was isolated
3. customPurification by chromatography on a column of Silica Gel