Reaction Steps
A solution of benzyl 2-acetamido-3-O-allyl-2-deoxy-α-D-glucopyranoside 4 (ref.25; 10.5 g, 29.9 mmol) and benzyl bromide (7.7 ml, 65 mmol) in dry N,N-dimethylformamide (75 ml) was gradually added to a stirred suspension of sodium hydride (60% in mineral oil; 2.8 g, 70 mmol) in N,N-dimethylformamide (25 ml) under argon at 0° C. during 30 min, and the whole was stirred at room temperature for 24 h. A solid carbon dioxide was added and the excess of sodium hydride was decomposed with water and the mixture was evaporated. The solid residue was partitioned between toluene (500 ml) and water (100 ml), organic layer was washed with water (2×100 ml), dried (MgSO4) and evaporated. Chromatography of the residue on a silica gel column (500 g) in toluene-ethyl acetate (2:1) afforded 14.2 g (89%) of 5 as white solid, which was crystallized from toluene-n-heptane; m.p. 152-153° C., [α]D+109° (c 0.5, chloroform); ref.39: m.p. 137.5-138.5° C. (diethyl ether), [α]D+102° (c 1.0, chloroform). IR and 1H NMR spectra correspond with the respective data for the authentic sample described in ref.39. 1H NMR: 7.16-7.37 m, 15H (H-arom.); 5.87 ddt, 1 H, J=5.8, 5.8, 10.3, 17.1 (OCH2—CH═CH2); 5.56 bd, 1 H, J=9.6 (NHCOCH3); 5.23 dq, 1 H, J=1.7, 1.7, 1.7, 17.1 (OCH2—CH═CHH); 5.17 dq, 1 H, J=1.5, 1.5, 1.5, 10.3 (OCH2—CH═CHH); 4.90 d, 1 H, J=3.8 (H-1); 4.79 d, 1 H, J=10.6 (CH2-Ph); 4.70 d, 1 H, J=11.7 (CH2-Ph); 4.63 d, 1 H, J=12.2 (CH2-Ph); 4.53 d, 1 H, J=12.2 (CH2-Ph); 4.50 d, 1 H, J=10.6 (CH2-Ph); 4.45 d, 1 H, J=11.7 (CH2-Ph); 4.30 ddt, 1 H, J=1.4, 1.4, 5.2, 12.6 (OCHHCH═CH2); 4.29 ddd, 1 H, J=3.8, 9.6, 10.6 (H-2); 4.09 ddt, 1 H, J=1.4, 1.4, 6.1, 12.6 (OCHHCH═CH2); 3.81 ddd, 1 H, J=2.0, 4.1, 9.9 (H-5); 3.73 dd, 1 H, J=4.1, 10.6 (H-6a); 3.69 dd, 1 H, J=8.8, 9.9 (H-4); 3.64 dd, 1 H, J=2.0, 10.6 (H-6b); 3.59 dd, 1 H, J=8.8, 10.6 (H-3); 1.96 s, 3 H (NHCOCH3). 13C NMR: 169.7 (NHCOCH3), 138.0 (2C), 137.2 (C-arom.), 135.0 (OCH2—CH═CH2), 128.6 (2C), 128.4 (3C), 128.2 (2C), 128.1 (2C), 128.0 (2C), 127.8, 127.8 (2C), 127.6 (C-arom.), 116.9 (OCH2—CH═CH2), 97.3 (C-1), 80.8 (C-3), 78.0 (C-4), 75.0 (CH2-Ph), 73.7 (CH2-Ph), 73.4 (OCH2—CH═CH2), 71.2 (C-5), 69.6 (CH2-Ph), 68.5 (C-6), 52.5 (C-2), 23.4 (NHCOCH3). For C32H37NO6 calculated: relative molecular mass 531.6, monoisotopic mass 531.3. FAB MS, m/z: 532.2 [M+H]+. For C32H37NO6 (531.6) calculated: 72.29% C, 7.01% H, 2.63% N; found 72.44% C, 6.98% H, 2.68% N.
