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 (8), 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).
