1966
DONG DengXiang, et al. Sci China Chem September (2010) Vol.53 No.9
Hz, PhCH2), 4.76 (d, 1H, J 11.4 Hz, PhCH2), 4.75–4.69 (m,
2H, H-3, H-5′), 4.52 (d, 1H, J 12.0 Hz, PhCH2), 4.48 (dd,
1H, J5″,6″b 6.4 Hz, J6″a,6″b 10.4 Hz, H-6″b), 4.44–4.36 (m, 5H,
PhCH2, H-2), 4.31–4.25 (m, 3H, PhCH2, H-4, H-6″a), 3.97
(dd, 1H, J5,6a 2.7 Hz, J6a,6b 11.3 Hz, H-6a), 3.92 (dd, 1H, J2′,3′
10.3 Hz, J3′,4′ 2.7 Hz, H-3′), 3.81 (dd, 1H, J1′,2′ 3.5 Hz, J2′,3′
10.3 Hz, H-2′), 3.76–3.69 (m, 2H, H-5″, H-6b), 3.66–3.64
(m, 1H, H-4′), 3.41–3.39 (m, 1H, H-5), 3.37 (s, 3H, OCH3),
2.46–2.40 (m, 1H, H-4″b), 1.75–1.65 (m, 1H, H-4″a), 1.33
(d, 3H, J5′,6′ 6.5 Hz, H-6′); 13C NMR (100.6 MHz, CDCl3):
166.07, 165.79, 164.78 (3 × C=O, Bz), 138.88, 138.28,
137.88, 133.88, 133.37, 133.17, 131.87, 129.79, 129.71,
129.66, 128.69, 128.63, 128.44, 128.39, 128.12, 128.06,
128.00, 127.98, 127.91, 127.78, 127.07, 126.85, 123.38
(C-arom, CH-arom), 99.50 (C-1″), 99.07 (C-1), 97.53 (C-1′),
79.53 (C-3′), 78.42 (C-4′), 75.33 (C-4), 75.21 (C-2′), 74.87
(C-5), 73.48 (C-3), 72.71 (C-2″), 71.69 (C-3″), 69.43 (C-5″),
66.52 (C-5′), 74.77, 73.64, 72.73, 72.14 (4 × PhCH2), 67.71
(C-6), 65.57 (C-6″), 56.60 (OCH3), 56.03 (C-2), 33.30 (C-4″),
16.83 (C-6′); HRMS (CI) m/z: Calcd for C76H77O18N2
H-6b), 3.49 (s, 3H, OCH3), 3.10 (dd, 1H, J1″,2″ 7.8 Hz, J2″,3″
9.4 Hz, H-2″), 2.02 (s, 3H, COCH3), 2.01–1.96 (m, 1H,
H-4″a), 1.28–1.18 (m, 1H, H-4″b), 1.18 (d, 3H, J5′,6′ 6.6 Hz,
H-6′). 13C NMR (100.6 MHz, D2O): 174.81 (C=O),
102.11 (C-1, C-1″), 99.16 (C-1′), 75.78 (C-2″), 75.72 (C-3),
75.63 (C-5), 73.87 (C-4), 72.72 (C-5″), 72.32 (C-4′), 70.46
(C-3″), 69.59 (C-2′), 68.03 (C-3′), 66.82 (C-5′), 64.51 (C-6),
60.08 (C-6″), 57.49 (OCH3), 55.98 (C-2), 35.06 (C-4″),
22.59 (CH3CO), 15.78 (C-6′); HRMS (FAB) m/z: Calcd for
C21H37O14NNa [M+Na+] 550.2112. Found 550.2133.
2.9 Methyl (4-O-acetyl-2,6-di-O-benzoyl-3-deoxy--D-xylo-
hexopyranosyl)-(1→4)-6-O-benzyl-2-deoxy-2-phthalimido-
-D-glucopyranoside (13)
A solution of acceptor 7 (1.5 g, 3.62 mmol) and donor 12
(1.83 g, 3.61 mmol) in anhydrous dichloromethane (100 mL)
was stirred with 10 g of 4 Å powdered molecular sieves for
40 min at room temperature under an argon atmosphere,
then cooled to 30 °C. 10 min later, N-iodosuccinimide
(1.63 g, 7.25 mmol) was introduced to the reaction mixture
followed by addition of triflic acid (98 L, 1.07 mmol). The
mixture was stirred at 30 °C for 1 h. TLC indicates that the
reaction was finished. Et3N was added, then the reaction
mixture was filtrated and the organic phase was treated by
saturated Na2S2O3 solution and NaHCO3 solution. The or-
ganic phase was washed with a saturated NaCl solution,
then with water. After being dried over MgSO4, filtered and
concentrated, the residue was purified by flash chromatog-
raphy, eluting with toluene-ethyl acetate (9:1) to give 2.04 g
of compound 13 (70%): Rf 0.54 (1:1 cyclohexane-ethyl ace-
tate); []D 10 (c 1, CHCl3); 1H NMR (400 MHz, CDCl3):
8.11–7.25 (m, 19H, arom), 5.35 (ddd, 1H, J1′,2′ 8.1 Hz, J2′,3′a
5.2 Hz, J2′,3′b 11.9 Hz, H-2′), 5.24–5.21 (m, 1H, H-4′), 5.13
(d, 1H, J1,2 8.5 Hz, H-1), 4.82 (d, 1H, J1′,2′ 8.1 Hz, H-1′),
4.65 (dd, 1H, J5′,6′a 3.3 Hz, J6′a,6′b 11.6 Hz, H-6′a), 4.56 (dd,
1H, J2,3 8.1 Hz, J3,4 10.8 Hz, H-3), 4.42 (d, 1H, J 12.3 Hz,
PhCH2) 4.30 (d, 1H, J 12.3 Hz, PhCH2), 4.29–4.22 (m, 2H,
H-2, H-6′b), 4.22 (d, 1H, J 11.6 Hz, PhCH2), 4.17–4.12 (m,
1H, H-5′), 3.84–3.78 (m, 1H, H-4), 3.71–3.61 (m, 3H, H-5,
H-6a, H-6b), 3.45 (s, 3H, OCH3), 2.56 (ddd, 1H, J 3′a,3′b 14.3
Hz, J3′a,4′ 3.0 Hz, J2′,3′a 5.2 Hz, H-3′a), 2.19 (s, 3H, CH3CO),
1.92 (ddd, 1H, J 3′a,3′b 14.3 Hz, J2′,3′b 11.9 Hz, J3′b,4′ 3.1 Hz,
H-3′b). 13C NMR (100.6 MHz, CDCl3): 169.95, 166.19,
164.94 (3 × C=O, Bz), 138.29, 133.77, 133.41, 133.12,
132.10, 131.74, 129.72, 129.68, 129.33, 128.98, 128.95,
128.91, 128.46, 128.33, 128.19, 128.10, 127.41, 127.26,
125.27, 125.18, 123.31, 123.06 (C-arom, CH-arom), 102.99,
98.9 (C-1, C-1′), 82.35, 75.07, 74.04, 69.70, 67.71, 67.11 (6×
CH, C-3, C-4, C-5, C-2′, C-4′, C-5′), 73.02 (PhCH2), 68.04
(C-6), 62.96 (C-6′), 56.53, 55.74 (OCH3, C-2), 32.95 (C-3′),
20.81 (CH3CO). HRMS (CI) m/z: Calcd for C44H47O14N2
+
[M+NH4 ] 1305.5171. Found 1305.5187.
2.8 Methyl (4-deoxy--D-xylo-hexopyranosyl)-(1→4)–
[-L-fucopyranosyl-(1→3)]-2-deoxy-2-acetamido--D-glu-
copyranoside (1)
A solution of compound 11 (245 mg, 0.19 mmol) in H2O-
EtOH-NH2NH2·H2O (1/1/18, 10 mL) was refluxed over-
night. The reaction mixture was evaporated. The residue
was dissolved in a mixture of pyridine (2 mL) and acetic
anhydride (1 mL), and the solution was stirred overnight at
30 °C. When TLC indicates that the reaction was finished
the residual pyridine and acetic anhydride were removed by
co-evaporation with toluene. The residue was dissolved in a
solution of NaOMe-MeOH (0.05 M, 2 mL) at room tem-
perature under argon. The reaction mixture was stirred
overnight. After neutralizing with Amberlite IR 120 (H+)
until pH 7, the solution was filtrated and the filtrate was
concentrated. The residue (Rf 0.5, DCM/MeOH 10:1) was
dissolved in methanol (3 mL), Pd/C (55 mg) was added to
the solution, then the reaction mixture was stirred overnight
under an atmosphere of hydrogen at room temperature. Af-
ter filtration, the filtrate was concentrated. The residue was
purified by flash chromatography, eluting with ethyl ace-
tate-isopropanol-H2O (1:1:1) to give 63 mg of compound 1
as a white solid (63% for 4 steps): Rf 0.45 (1:1:1 ethyl ace-
1
tate-isopropanol-H2O); []D +48 (c1, H2O); H NMR (400
MHz, D2O): 5.09 (d, 1H, J1′,2′ 4.0 Hz, H-1′), 4.84–4.80 (m,
1H, H-5′), 4.46 (d, 1H, J1,2 7.9 Hz, H-1), 4.43 (d, 1H, J1″,2″
7.8 Hz, H-1″), 4.01 (dd,1H, J5″,6″a 1.8 Hz, J6″a,6″b 12.3 Hz,
H-6″a), 3.93–3.82 (m, 5H, H-2, H-4, H-5, H-3′, H-6″b),
3.78–3.72 (m, 2H, H-4′, H-3″), 3.69 (dd, 1H, J1′,2′ 4.0 Hz,
J2′,3′ 10.4 Hz, H-2′), 3.63–3.54 (m, 4H, H-3, H-5″, H-6a,
+
[M+NH4 ] 827.3027. Found 827.3043.