Reaction Steps
To a stirred solution of methyl 2,3,4-tri-O-benzyl-6-O-(N-trifluoroacetyl-5-aminopentyl)-β-D-glucopyranoside (799 mg, theoretically 1.71 mmol, structure (13) from Example 4) in 10 mL of ethanol at room temperature was added a solution of 5M (3 mL, 15 mmol). The solution was heated to reflux for 2 hours. The solvents were removed under reduced pressure. The reaction mixture was diluted with dichloromethane (70 mL) and washed with aqueous HCl (25 mL, 15 mmol). The water layer was re-extracted with dichloromethane (3×50 mL), and the combined organic layers were washed with saturated aqueous NaCl (1×75 mL) and dried over magnesium sulfate. Concentration and crystallization from ethyl acetate/petroleum ether provided pure analog having structure (9), methyl 6-O-(5-aminopentyl)-2,3,4-tri-O-benzyl-β-D-glucopyranoside, (675 mg, 72% from methyl 2,3,4-tri-O-benzyl-6-O-trifluoromethylsulfonyl-β-D-glucopyranoside) as a white solid: m.p. 95-95.5° C.; RF 0.19 (6% methanol in dichloromethane); 1H NMR (500 MHz, CDCl3) δ 7.35-7.24 (m, 15H), 4.92 (d, J=7.5 Hz 1H), 4.90 (d, J=7.6 Hz, 1H), 4.85 (d,J=11.0 Hz, 1H), 4.78 (d, J=11.0 Hz, 1H), 4.70 (d, J=11.0 Hz, 1H), 4.60 (d, J=11.0 Hz, 1H), 4.32 (7.8, 1H), 3.66-3.59 (m, 3H), 3.56 (s, 3H), 3.48-3.36 (m, 3H), 2.94 (dd, J=12.5, 2.1 Hz, 1H), 2.68 (dd, J=12.0, 6.8 Hz, 1H), 2.64-2.53 (m, 2H), 1.71 (s, 2H), 1.59-1.53 (m, 2H), 1.51-1.45 (m, 2H), 1.42-1.36 (m, 2H), 13C NMR (500 MHz, CDCl3) δ 138.55, 138.47, 138.17, 128.39, 128.33, 128.03, 127.95, 127.85, 127.77, 127.60, 127.57, 104.72, 84.56, 82.45, 79.74, 75.66, 75.02, 74.74, 74.16, 62.62, 57.20, 50.69, 49.72, 32.49, 29.65, 23.37; IR (thin film) 3280(m), 3095(w), 3065(w), 3035(w), 2935(s), 2915(s), 2860(s), 1496(w), 1454(m), 1404(w), 1393(w), 1358(m), 1214(m), 1115(s), 1072(s), 1037(m), 1027(m), 1009(m), 911(w), 826(s), 747(s), 696(s) cm−1; HRMS m/e calc'd for C33H43O6N (M+H): 550.3168, found 550.3179; [α]D20+9.3° (c=0.15, acetonitrile).
