Acetic Anhydride → beta-Maltose

Participants

Reaction Steps

By the method above, but beginning with maltose monchydrate (52), the title compound is obtained as a mixture of diastereomers. To a solution of maltose monohydrate 52 (3.5 g, 9.7 mmol) in 40 mL of pyridine at room temperature is added acetic anhydride (20 mL, 210 mmol) and DMAP (0.10 g, 0.82 mmol). The solution is stirred at room temperature for 5 h and concentrated. The residue is dissolved in 200 mL of CH2Cl2, washed with 1N HCl (4×100 mL), dried over Na2SO4, and concentrated to afford 6.6 g (100%) of peracetylated maltose as the β anomer maltose-47: Rf 0.58 (75% EtOAc/petroleum ether); 1H NMR (CDCl3, 270 MHz) δ 5.74 (d, J=8.2 Hz, 1H, H-1), 5.26-5.41 (m, 3H), 4.94-5.09 (m, 2H), 4.86 (dd, J=10.5, 4.0 Hz, 1H), 4.45 (dd, J=12.4, 2.3 Hz, 1H), 4.19-4.27 (m, 2H), 4.0-4.07 (m, 2H), 3.91-3.96 (m, 1H), 3.80-3.87 (m, 1H), 2.14 (s, 3H), 2.10 (s, 6H), 2.05 (s, 3H), 2.03 (s, 3H), 2.01 (s, 6H), 2.00 (s, 3H).

Provenance & Evidence