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HETEROCYCLES, Vol. 75, No. 5, 2008
concentrated under reduced pressure. The residue was purified by silica gel column chromatography
(CH2Cl2: hexane: AcOEt=10:5:1) and crystallized from a mixed solvent of CH2Cl2/hexane (1:2) to give a
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colorless solid 3 (20.6 g, 49%). 3: mp 139-140 °C (decomp). [α]D 63.7 (c 0.3, CHCl3). IR (KBr) cm-1:
1763, 1731, 1272, 707. 1H-NMR (CDCl3) δ: 3.11 (3H, s), 3.70 (3H, s), 4.79 (1H, d, J=9.8 Hz), 5.54 (1H,
dd, J=3.4, 9.8 Hz), 5.75 (1H, t, J=9.8 Hz), 6.17 (1H, t, J=9.8 Hz), 6.41 (1H, d, J=3.4 Hz), 7.31-7.57 (9H,
13
m), 7.88-7.99 (6H, m). C-NMR (CDCl3) δ: 39.5, 53.1, 68.7, 69.1, 69.5, 70.8, 95.9, 128.4, 128.4, 128.5,
128.5, 128.5, 128.6, 129.7, 129.8, 129.9, 133.5, 133.6, 133.8, 165.0, 165.2 165.3, 166.7. FAB-MS m/z:
597 (M-H)-. Anal. Calcd for C29H26O12S (MW: 598.58): C, 58.19; H, 4.38. Found: C, 58.20; H, 4.30.
1-(2,3,4-Tri-O-benzoyl-6-methyl–β-D-glucopyranuronosyl)pyridinium hydroxide (6a)
A solution of pyridine (15.8 mg, 0.20 mmol) and 3 (144 mg, 0.24 mmol) in anhydrous CHCl3 (1 mL) was
refluxed for 24 h under argon. After cooling, the reaction mixture was diluted with CH2Cl2 (2 mL), then
washed with water (2 mL), dried over Na2SO4, and concentrated under reduced pressure. The residue was
purified by silica gel column chromatography (CH2Cl2: MeOH=5:1) to give the title compound 6a as a
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white powder (62.0 mg, 52%). 6a: mp 140-144 °C (decomp). [α]D -5.0 (c 0.4, CHCl3). IR (KBr) cm-1:
3422, 1734, 1261, 710. 1H-NMR (CDCl3) δ: 3.65 (3H, s), 5.31 (1H, d, J=9.9 Hz), 5.79 (1H, t, J=9.3 Hz),
5.90 (1H, t, J=9.6 Hz), 6.45 (1H, t, J=9.4 Hz), 7.24-7.28 (2H, m), 7.35 (2H, t, J=7.8 Hz), 7.40-7.45 (3H,
m), 7.49-7.54 (1H, m), 7.54-7.59 (1H, m), 7.87-7.80 (4H, m), 8.01-8.09 (4H, m), 8.34 (1H, d, J=9.2 Hz),
8.52 (1H, t, J=7.8 Hz), 9.86 (2H, d, J=5.6 Hz). MS (ESI) m/z: 582[M-OH]+. HR-MS (ESI) m/z: 582.17577
(Calcd for C33H28NO9: 582.17641).
1-(2,3,4-Tri-O-benzoyl-6-methyl– β-D-glucopyranuronosyl)-2-methylpyridinium hydroxide (6b)
The same procedure as the synthesis of 6a was applied for the synthesis of the title compound (6b) from
2-methylpyridine (18.6 mg, 0.20 mmol) to give 6b (42.0 mg, 42%) as pale brownish amorphous foam. 6b:
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1
[α]D -6.9 (c 0.4, CHCl3). IR (KBr) cm-1: 3415, 1734, 1258, 711. H-NMR (CDCl3) δ: 3.40 (3H,s), 3.62
(3H, s), 5.76 (1H, t, J=9.4 Hz), 5.89 (1H, t, J=9.8 Hz), 6.07 (1H, d, J=10.0 Hz), 6.59 (1H, t, J=9.5 Hz),
7.24-7.31 (2H, m), 7.34-7.43 (5H, m), 7.51-7.57 (2H, m), 7.74 (1H, d, J=7.3Hz), 7.80-7.82 (4H, m),
8.01-8.03 (3H, m), 8.37-8.40 (2H, m), 9.42 (1H, br s). MS (ESI) m/z: 596[M-OH]+. ESI-MS m/z:
596.19188 (Calcd for C34H30NO9: 596.19206).
1-(2,3,4-Tri-O-benzoyl-6-methyl–β-D-glucopyranuronosyl)-3-methylpyridinium hydroxide (6c)
The same procedure as the synthesis of 6a was applied for the synthesis of the title compound (6c) from
3-methylpyridine (18.6 mg, 0.20 mmol) to give 6c (61.0 mg, 50 %) as white powder. 6c: mp 133-136 °C
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1
(decomp). [α]D -23.6 (c 0.3, CHCl3). IR (KBr) cm-1: 3415, 1734, 1258, 711. H-NMR (CDCl3) δ: 2.53
(3H,s), 3.64 (3H, s), 5.32 (1H, d, J=9.9 Hz), 5.72 (1H, t, J=9.3 Hz), 5.86 (1H, t, J=9.6 Hz), 6.47 (1H, t,
J=9.3 Hz), 7.25-7.29 (1H, m), 7.32-7.44 (6H, m), 7.50-7.58 (2H, m), 7.82 (2H, d, J=7.3 Hz), 7.89-7.93
(3H, m), 8.02 (2H, d, J=7.3 Hz), 8.27 (1H, d, J=7.8 Hz), 8.32 (1H, d, J=9.2 Hz), 9.60 (1H, s), 9.68 (1H, d,