T. Kumazawa et al. / Carbohydrate Research 329 (2000) 507–513
511
0.35 (5:1 hexane–EtOAc); IR (NaCl): 3030,
gradually increase to −42 °C, and the stirring
was continued for 30 min, then to −20 °C for
1 h, and finally to rt for 1 h. After adding
water, the resulting mixture was filtered
through a Celite® pad. The filtrate was ex-
tracted with CHCl3, and the organic layer was
dried over anhyd MgSO4. The solvent was
evaporated under reduced pressure, and the
resulting syrup was chromatographed on a
silica gel column (5:1 hexane–EtOAc) to give
6 (4.88 g, 75%) as a colorless highly viscous
oil: [h]2D2 −16° (c 1.00, CHCl3); Rf 0.30 (5:1
hexane–EtOAc); IR (NaCl): 3030, 2864, 1621,
1593, 1430, 1360, 1273, 1165, 1097, 1066
2866, 1701, 1597, 1454, 1350, 1257, 1159, 1099
1
cm−1; H NMR (Me2SO-d6 at 180 °C): l 2.20
(s, 3 H, ArMe), 2.29 (s, 3 H, ArMe), 2.33 (s, 3
H, ArAc), 3.30–3.62 (m, 2 H, H-4%, 5%) 3.49
(dd, 1 H, J 5.0, 11.2 Hz, H-6%a), 3.53 (dd, 1 H,
J 8.3, 8.5 Hz, H-3%), 3.63 (dd, 1 H, J 2.0, 11.2
Hz, H-6%b), 4.14 (d, 1 H, J 11.1 Hz, benzylic
CH2), 4.35 (dd, 1 H, J 8.5, 9.7 Hz, H-2%), 4.40
(s, 2 H, benzylic CH2), 4.41 (d, 1 H, J 11.1 Hz,
benzylic CH2), 4.48 (d, 1 H, J 11.5 Hz, ben-
zylic CH2), 4.64 (d, 1 H, J 11.5 Hz, benzylic
CH2), 4.69 (d, 1 H, J 11.7 Hz, benzylic CH2),
4.72 (d, 1 H, J 9.7 Hz, H-1%), 4.73 (d, 1 H, J
11.7 Hz, benzylic CH2), 4.79 (d, 1 H, J 11.5
Hz, benzylic CH2), 5.02 (d, 1 H, J 11.5 Hz,
benzylic CH2), 5.07 (d, 1 H, J 12.0 Hz, ben-
zylic CH2), 5.10 (d, 1 H, J 12.0 Hz, benzylic
CH2), 5.15 (d, 1 H, J 12.8 Hz, benzylic CH2),
5.17 (d, 1 H, J 12.8 Hz, benzylic CH2), 6.71 (s,
1 H, ArH), 6.88–7.44 (m, 33 H, ArH);
FABMS (negative ion): m/z 988 [M−H]−.
Anal. Calcd for C65H64O9·0.5H2O: C, 78.21;
H, 6.56. Found: C, 78.00; H, 6.52.
1
cm−1; H NMR (Me2SO-d6 at 140 °C): l 2.31
(s, 3 H, ArMe), 2.53 (s, 3 H, ArAc), 3.41–3.46
(m, 2 H, H-4%, 5%) 3.57 (dd, 1 H, J 4.5, 10.4
Hz, H-6%a), 3.62 (dd, 1 H, J 8.4, 8.8 Hz, H-3%),
3.65 (d, 1 H, J 10.4 Hz, H-6%b), 4.15 (d, 1 H,
J 11.4 Hz, benzylic CH2), 4.29 (dd, 1 H, J 8.8,
9.8 Hz, H-2%), 4.41 (d, 1 H, J 11.4 Hz, benzylic
CH2), 4.42 (d, 1 H, J 12.4 Hz, benzylic CH2),
4.47 (d, 1 H, J 12.4 Hz, benzylic CH2), 4.55
(d, 1 H, J 11.3 Hz, benzylic CH2), 4.70 (d, 1
H, J 11.3 Hz, benzylic CH2), 4.73 (d, 1 H, J
11.7 Hz, benzylic CH2), 4.77 (d, 1 H, J 11.7
Hz, benzylic CH2), 4.82 (d, 1 H, J 9.8 Hz,
H-1%), 5.12 (d, 1 H, J 12.5 Hz, benzylic CH2),
5.14 (d, 1 H, J 12.5 Hz, benzylic CH2), 5.26
(d, 1 H, J 12.5 Hz, benzylic CH2), 5.28 (d, 1
H, J 12.5 Hz, benzylic CH2), 6.42 (s, 1 H,
ArH), 6.87–7.47 (m, 29 H, ArH), 13.70 (br. s,
1 H, ArOH); FABMS (negative ion): m/z 883
[M−H]−. Anal. Calcd for C57H56O9·2.5H2O:
C, 73.60; H, 6.38. Found: C, 73.41; H, 6.18.
6-Benzyloxy-2,4-bis(2-methylbenzyloxy)-3-
6 - Hydroxy - 2,4 - bis(2 - methylbenzyloxy) - 3-
(2,3,4,6-tetra-O-benzyl-i- -glucopyranosyl)-
D
acetophenone (8).—A soln of 7 (1.041 g 1.05
mmol) and 10% palladium-on-charcoal (52
mg) in EtOAc (50 mL) was stirred at rt for a
total of 2 h under an atmosphere of H2, and
the progress of the reaction was monitored by
TLC. After filtering, the filtrate was concen-
trated under reduced pressure, and the residue
was chromatographed on a silica gel column
(8:1 hexane–EtOAc) to give 8 (380 mg, 40%)
as a colorless highly viscous oil: [h]2D2 +10° (c
1.00, CHCl3); Rf 0.48 (5:1 hexane–EtOAc); IR
(NaCl): 3030, 2862, 1614, 1581, 1454, 1362,
(2,3,4,6-tetra-O-benzyl-i- -glucopyranosyl)-
D
acetophenone (7).—A mixture of 6 (4.53 g,
5.11 mmol), anhyd K2CO3 (1.06 g, 7.66 mmol,
1.5 equiv), and 2-methylbenzyl chloride (862
mg, 6.13 mmol, 1.2 equiv) in DMF (120 mL)
was stirred for 3 h at 80 °C. The reaction
mixture was poured into 1 M HCl (500 mL)
and extracted with EtOAc. The organic layer
was washed with water and brine, and then
dried over anhyd MgSO4. The solvent was
evaporated under reduced pressure, and the
resulting syrup was chromatographed on a
silica gel column (8:1 hexane–EtOAc) to af-
ford 7 (5.11 g, quant) as a colorless highly
viscous oil: [h]2D2 −18° (c 1.00, CHCl3); Rf
1267, 1176, 1095, 1063 cm−1
;
1H NMR
(Me2SO-d6 at 180 °C): l 2.17 (s, 3 H, ArMe),
2.34 (s, 3 H, ArMe), 2.39 (s, 3 H, ArAc),
3.27–3.34 (m, 2 H, H-4%, 5%) 3.46 (dd, 1 H, J
4.7, 11.0 Hz, H-6%a), 3.52 (dd, 1 H, J 8.3, 9.0
Hz, H-3%), 3.61 (d, 1 H, J 11.0 Hz, H-6%b), 4.18
(d, 1 H, J 11.4 Hz, benzylic CH2), 4.34 (dd, 1
H, J 8.3, 9.0 Hz, H-2%), 4.39 (s, 2 H, benzylic
CH2), 4.44 (d, 1 H, J 11.4 Hz, benzylic CH2),
4.47 (d, 1 H, J 11.7 Hz, benzylic CH2), 4.63
(d, 1 H, J 11.7 Hz, benzylic CH2), 4.68 (d, 1
H, J 11.7 Hz, benzylic CH2), 4.72 (d, 1 H, J
9.0 Hz, H-1%), 4.73 (d, 1 H, J 11.7 Hz, benzylic