Glycoconj J (2012) 29:181–188
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galactopyranoside (8) A solution of compound 4 (1.4 g,
2.51 mmol) and compound 5 (1.9 g, 4.0 mmol) in anhydrous
CH2Cl2-Et2O (12 mL, 1:1 v/v) was cooled to −20 °C. To the
cooled reaction mixture was added HClO4-SiO2 (200 mg)
and the reaction mixture was allowed to stir at same tem-
perature for 1 h. The reaction mixture was filtered and
washed with CH2Cl2 (100 mL). The combined organic layer
was washed with satd. NaHCO3 and water, dried (Na2SO4)
and concentrated. The crude product was purified over SiO2
using hexane-EtOAc (5:1) as eluant to give pure compound
8 (1.4 g, 64 %). Colourless oil; [α]D25 +73.8 (c 1.2, CHCl3);
IR (neat): 3024, 2936, 2362, 2100, 1751, 1374, 1212, 1043,
11.5 Hz, 1 H, PhCH2), 4.82 (d, J011.5 Hz, 1 H, PhCH2),
4.78 (d, J08.0 Hz, 1 H, H-1C), 4.66–4.61 (2 d, J012.0 Hz
each, 2 H, PhCH2), 4.51–4.43 (2 d, J011.5 Hz each, 2 H,
PhCH2), 4.15 (d, J02.5 Hz, 1 H, H-4D), 5.30 (dd, J010.5,
3.0 Hz, 1 H, H-3D), 4.07 (br s, 1 H, H-5C), 4.05 (d, J0
3.0 Hz, 1 H, H-4C), 3.95–3.92 (m, 1 H, H-6aC), 3.78 (t, J0
10.0 Hz each, 1 H, H-2C), 3.69 (s, 3 H, OCH3), 3.60–3.51
(m, 4 H, H-2D, H-5D, H-6aD, H-6bC), 3.43 (dd, J010.0,
3.0 Hz, 1 H, H-3C), 3.33–3.30 (m, 1 H, H-6bD); 13C NMR
(125 MHz, CDCl3): δ 155.3–114.5 (Ar-C), 103.3 (C-1C),
101.0 (PhCH), 99.5 (C-1D), 80.6 (C-3C), 78.1 (C-2C), 75.6
(C-4C), 75.0 (PhCH2), 73.6 (PhCH2), 73.3 (C-4D), 73.1 (C-
5D), 72.7 (PhCH2), 68.9 (C-6C), 67.8 (C-3D), 67.0 (C-6D),
62.7 (C-5C), 61.4 (C-2D), 55.7 (OCH3); ESI-MS: 854.3 [M
+Na]+; Anal. Calcd. for C47H49N3O11 (831.34): C, 67.86;
H, 5.94; found: C, 67.65; H, 6.18.
1
767, 670 cm−1; H NMR (500 MHz, CDCl3): δ 7.30–7.15
(m, 15 H, Ar-H), 6.90 (d, J09.0 Hz, 2 H, Ar-H), 6.70 (d, J0
9.0 Hz, 2 H, Ar-H), 5.36 (d, J02.0 Hz, 1 H, H-4D), 5.30 (dd,
J010.5, 3.5 Hz, 1 H, H-3D), 4.95 (d, J03.5 Hz, 1 H, H-1D),
4.94 (d, J011.0 Hz, 1 H, PhCH2), 4.82 (d, J011.0 Hz, 1 H,
PhCH2), 4.72 (d, J07.5 Hz, 1 H, H-1C), 4.70–4.65 (m, 2 H,
H-5D), 4.45 (m, 1 H, PhCH2), 4.08 (d, J03.0 Hz, 1 H, H-
4C), 3.90–3.83 (m, 3 H, H-5C, H-6aC, H-6aD), 3.67 (s, 3 H,
OCH3), 3.60 (dd, J011.0, 4.0 Hz, 1 H, H-2D), 3.58–3.52 (m,
2 H, H-2C, H-6bD), 3.48–3.45 (m, 1 H, H-6bC), 3.40 (dd, J0
10.0, 3.0 Hz, 1 H, H-3C), 2.02, 1.97, 1.80 (3 s, 9 H, 3
COCH3); 13C NMR (125 MHz, CDCl3): δ 170.1 (2 C),
169.8 (3 COCH3), 155.7–114.5 (Ar-C), 103.2 (C-1C), 98.5
(C-1D), 79.7 (C-3C), 78.7 (C-2C), 75.2 (PhCH2), 73.8 (C-
4C), 73.5 (PhCH2), 73.3 (PhCH2), 72.9 (C-5C), 68.8 (C-3D),
67.3 (C-4D), 67.0 (C-6D), 66.2 (C-5D), 60.6 (C-6C), 58.0 (C-
2D), 55.6 (OCH3), 20.2, 20.6 (2 C) (3 COCH3); ESI-MS:
892.3 [M+Na]+; Anal. Calcd. for C46H51N3O14 (869.34): C,
63.51; H, 5.91; found: C, 63.28; H, 6.15.
p-Methoxyphenyl (2,3,4,6-tetra-O-acetyl-β-D-galactopyra-
nosyl)-(1→3)-(4,6-O-benzylidene-2-azido-2-deoxy-α-D-
galactopyranosyl)-(1→4)-2,3,6-tri-O-benzyl-β-D-galacto-
pyranoside (10) To a solution of compound 9 (800.0 mg,
0.96 mmol) and compound 6 (450.0 mg, 1.14 mmol) in
anhydrous CH2Cl2 (5 mL) was added MS 4 Å (1.0 g) and
the reaction mixture was stirred at room temperature under
argon for 30 min. The reaction mixture was cooled to −40 °C
and NIS (280.0 mg, 1.24 mmol) and HClO4-SiO2 (15.0 mg)
were added to it and the reaction mixture was allowed to stir at
same temperature for 45 min. The reaction mixture was fil-
tered through a Celite® bed and washed with CH2Cl2
(50 mL). The organic layer was successively washed with
5 % Na2S2O3, satd. NaHCO3 and water, dried (Na2SO4) and
concentrated. The crude product was purified over SiO2 using
hexane-EtOAc (5:1) as eluant to give pure compound 10
(870.0 mg, 78 %). Colourless oil; [α]D25 +80 (c 1.2, CHCl3);
IR (neat): 3474, 2932, 2868, 2117, 1757, 1502, 1226, 1100,
1079, 1056, 737, 699 cm−1; 1H NMR (500 MHz, CDCl3): δ
7.42–7.17 (m, 20 H, Ar-H), 6.94 (d, J09.0 Hz, 2 H, Ar-H),
6.72 (d, J09.0 Hz, 2 H, Ar-H), 5.33 (d, J03.5 Hz, 1 H, H-4E),
5.31 (s, 1 H, PhCH), 3.40 (dd, J08.0 Hz each, 1 H, H-2E),
5.01 (d, J03.5 Hz, 1 H, H-1D), 4.97 (d, J011.5 Hz, 1 H,
PhCH2), 4.95 (dd, J010.5, 3.0 Hz, 1 H, H-3E), 4.84 (d, J0
11.0 Hz, 1 H, PhCH2), 4.78 (d, J08.0 Hz, 1 H, H-1E), 4.76 (d,
J07.5 Hz, 1 H, H-1C), 4.70–4.60 (2 d, J011.5 Hz each,
PhCH2), 4.49–4.41 (2 d, J011.0 Hz each, PhCH2), 4.20 (d,
J03.0 Hz, 1 H, H-4D), 4.17 (d, J03.5 Hz, 1 H, H-4C), 4.12–
4.10 (m, 1 H, H-6aE), 4.07–4.04 (m, 1 H, H-6bE), 4.03 (br s, 1
H, H-5C), 3.99 (dd, J010.5, 3.0 Hz, 1 H, H-3D), 3.95–3.88 (m,
2 H, H-5E, H-6aC), 3.79–3.76 (m, 2 H, H-2C, H-2D), 3.69 (s, 3
H, OCH3), 3.60–3.55 (m, 3 H, H-5D, H-6aD, H-6bC), 3.44 (dd,
J010.0, 3.0 Hz, 1 H, H-3C), 3.37–3.35 (m, 1 H, H-6bD), 2.06,
2.00, 1.93, 1.90 (4 s, 12 H, 4 COCH3); 13C NMR (125 MHz,
CDCl3): δ 170.4, 170.3, 170.2, 169.5 (4 COCH3), 155.4–
114.5 (Ar-C), 103.4 (C-1E), 103.4 (C-1C), 100.5 (PhCH),
p-Methoxyphenyl (4,6-O-benzylidene-2-azido-2-deoxy-α-D-
galactopyranosyl)-(1→4)-2,3,6-tri-O-benzyl-β-D-galacto-
pyranoside (9) A solution of compound 8 (1.2 g,
1.38 mmol) in 0.1 M CH3ONa in CH3OH (20 mL) was
allowed to stir at room temperature for 2 h. The reaction
mixture was neutralized with Dowex 50 W X8 (H+) resin,
filtered and concentrated under reduced pressure. To a so-
lution of the deacetylated product in anhydrous CH3CN-
DMF (10 mL; 1:1 v/v) was added benzaldehyde dimethyl
acetal (0.4 mL, 2.66 mmol) followed by HClO4-SiO2
(50 mg) and the reaction mixture was allowed to stir at
room temperature for 5 h. The reaction mixture was filtered
and the solvents were removed under reduced pressure to
give the crude product, which was purified over SiO2 using
hexane-EtOAc (5:1) as eluant to give pure compound 9
25
(880.0 mg, 77 %). Colourless oil; [α]D +86.8 (c 1.2,
CHCl3); IR (neat): 3336, 2926, 2121, 1737, 1716, 1514,
1467, 1226, 1170, 1067, 756, 699 cm−1 1H NMR
;
(500 MHz, CDCl3): δ 7.38–7.17 (m, 20 H, Ar-H), 6.97 (d,
J09.0 Hz, 2 H, Ar-H), 6.72 (d, J09.0 Hz, 2 H, Ar-H), 5.34
(s, 1 H, PhCH), 4.97 (d, J03.5 Hz, 1 H, H-1D), 4.95 (d, J0