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H.-P. Knoben et al. / Carbohydrate Research 339(2004) 2821–2833
sodium hydrogencarbonate was added and the reaction
mixture was stirred for further 15min. The reaction mix-
ture was diluted with 10mL dichloromethane and
washed with saturated sodium hydrogencarbonate solu-
tion and water. The organic layer was dried over magne-
sium sulfate, filtered and evaporated. The residue could
be purified by column chromatography.
(b) One-pot procedure for glycosidation starting from
N-trichloroacetyl- and N-chloroacetyl 1-O-glycosyl car-
bamates. The acyl isocyanate (1.1mmol) was added to
a solution of the corresponding carbohydrate derivative
(1mmol) in 10mL of dry dichloromethane at room tem-
perature under an argon atmosphere. The reaction was
complete after 1min reaction time (TLC-monitoring).
To this solution 1.1mmol of the glycosyl acceptor and
4.10.3. Methyl 6-O-(2,3,4,6-tetra-O-acetyl-b-D-gluco-
pyranosyl)-2,3,4-tri-O-benzyl-a-D-glucopyranoside (11b).
Colourless syrup; Rf = 0.24 (cyclohexane/ethyl ace-
20
tate = 3:2). ½aꢀ ꢁ3.0 (c 1.4, CHCl3). Only clear 1H
D
NMR peaks are listed. 1H NMR (CDCl3): d 1.95,
1.99, 2.01, 2.01 (4s, 12H, 4CH3CO), 3.36(s, 3H,
3
3
OCH3), 3.51 (dd, 1H, JH1,H2 3.7Hz, JH2,H3 9.8Hz,
3
H-2a), 4.52 (d, 1H, JH1,H2 7.9Hz, H-1b), 4.58 (d, 1H,
3
3JH1,H2 3.7Hz, H-1a), 5.08 (dd (ꢁtꢀ), 1H, J 9.5Hz, H-
4), 5.17 (dd (ꢁtꢀ), 1H, 3J 9.5Hz, H-3), 5.31 (dd, 1H,
3
3JH1,H2 7.9Hz, JH2, H3 9.5Hz, H-2).
4.10.4. Methyl 6-O-(2,3,4,6-tetra-O-acetyl-b-D-galacto-
pyranosyl)-2,3,4-tri-O-benzyl-b-D-glucopyranoside (12b).
Colourless syrup; Rf = 0.30 (cyclohexane/ethyl ace-
20
200mg of powdered molecular sieves 4A were added.
tate = 1:1). ½aꢀ +7.0 (c 1.0, CHCl3). 1H NMR (CDCl3):
˚
D
The reaction mixture was stirred for 4h at room temper-
ature. After this period 1.0mmol of SnCl4 was added to
the solution dropwise under exclusion of moisture.
When the reaction was finished (TLC-monitoring)
sodium hydrogencarbonate was added and the reaction
mixture was stirred for further 15min. The reaction
mixture was diluted with 10mL dichloromethane and
washed with saturated sodium hydrogencarbonate
solution and water. The organic layer was dried over
magnesium sulfate, filtered and evaporated. The crude
disaccharide could be purified by column chromato-
graphy.
d Gluc.: 3.36(dd, 1H, J 9.0Hz, J 9.4Hz, H-4), 3.40 (dd,
1H, J 3.7Hz, J 9.0Hz, H-2), 3.51 (ddd, 1H, J 1.8Hz, J
4.0Hz, J 9.4Hz, H-5), 3.58 (s, 3H, OCH3), 3.64 (dd,
1H, J 9.0Hz, J 9.0Hz, H-3), 4.12 (dd, 1H, J 4.0Hz, J
12.1Hz, H-6), 4.12 (dd, 1H, J 1.8Hz, J 12.1Hz, H-60),
4.61 (d, 1H, J 3.7Hz, H-1); Gal.: d 1.92, 1.97, 1.99,
2.07 (4s, 12H, 4CH3CO), 3.66 (dd, 1H, J 7.0Hz, J
11.0Hz, H-60), 3.87 (ddd, 1H, J 0.9Hz, J 7.0Hz, J
7.0Hz, H-5), 4.12 (dd, 1H, J 7.0Hz, J 11.0Hz, H-6),
4.29 (d, 1H, J 7.0Hz, H-1), 4.98 (dd, 1H, J 3.4Hz, J
10.4Hz, H-3), 5.36(dd, 1H, J 3.7Hz, J 10.4Hz, H-2),
5.38 (dd, 1H, J 0.9Hz, J 3.4Hz, H-4).
4.10.1. Methyl 6-O-(2,3,4,6-tetra-O-benzyl-a-D-gluco-
pyranosyl)-2,3,4-tri-O-benzyl-a-D-glucopyranoside (10a).
Colourless syrup; Rf = 0.15 (cyclohexane/ethyl ace-
4.10.5. Methyl 4-O-(2,3,4,6-tetra-O-benzyl-a-D-gluco-
pyranosyl)-2,3,6-tri-O-benzyl-a-D-glucopyranoside (14a).
Colourless syrup; Rf = 0.15 (cyclohexane/ethyl ace-
tate = 6:1). Only clear 1H NMR peaks are listed. 1H
NMR (CDCl3): d 3.37 (s, 3H, OCH3), 3.43 (dd, 1H,
1
tate = 6:1). H NMR (CDCl3): d 3.35 (s, 3 H, OCH3),
3.44 (dd, 1H, JH1,H2 3.5Hz, JH2,H3 9.5Hz, H-2a),
3
3
3
3
3
3.53 (dd, 1H, JH1,H2 3.7Hz, JH2,H3 9.2Hz, H-2b),
3.56–3.60 (m, 1H, H-4b), 3.60–3.70 (m, 3 H, H-4a, H-
5a, H-6a), 3.71–3.86 (m, 4 H, H-5b, H-6b, H-60b, H-
60a), 3.94–3.98 (m, 1H, H-3a), 3.97–4.01 (m, 1H,
H-3b), 4.39–4.98 (m, 14H, PhCH2), 4.56(d, 1H,
3JH1,H2 3.0Hz, JH2,H3 9.5Hz, H-2a), 3.48 (dd, 1H
3
3JH1,H2 3.6Hz, JH2,H3 9.4Hz, H-2b), 4.02 (dd, 1H,
3
3JH3,H4 9.2Hz, JH2,H3 9.5Hz, H-3a), 4.27–5.05 (m,
3
14H, 7 · OCH2Ph), 5.69 (d, 1H, JH1,H2 3.6Hz, H-1b),
7.05–7.30 (m, 35H, Ar–H).
3
3JH1,H2 3.5Hz, H-1a), 4.97 (d, 1H, JH1,H2 3.7Hz, H-
1b), 7.10–7.40 (m, 35 H, Ar–H).
4.10.6. Methyl 4-O-(2,3,4,6-tetra-O-benzyl-a-D-gluco-
pyranosyl)-2,3,6-tri-O-benzyl-b-D-glucopyranoside (14b).
Colourless syrup; Rf = 0.15 (cyclohexane/ethyl ace-
tate = 6:1). Only clear 1H NMR peaks are listed. 1H
4.10.2. Methyl 6-O-(2,3,4,6-tetra-O-benzyl-a-D-gluco-
pyranosyl)-2,3,4-tri-O-benzyl-b-D-glucopyranoside (10b).
Colourless syrup; Rf = 0.15 (cyclohexane/ethyl ace-
tate = 6:1). Only clear 1H NMR peaks are listed. 1H
NMR (CDCl3): d 3.32 (s, 3H, OCH3), 3.40–3.71 (m,
6H, H-4a, H-5a, H-6a, H ꢁ 60a, H-3b, H-6b), 3.45–3.51
NMR (CDCl3): d 3.36(s, 3H, OCH ), 3.71 (dd, 1H,
3
3
3
JH5,H6 1.5Hz, JH6,H6 11.0Hz, H-6a), 4.40 (d, 1H,
0
3JH1,H2 7.0Hz, H-1b), 4.35–4.62 (m, 6 H, 3 · OCH2Ph),
4.55 (d, 1H, JH1,H2 3.0Hz, H-1a), 4.71–4.82 (m, 6H,
3
3
3
2
(m, 1H, H-2b), 3.52 (dd, 1H, JH1,H2 3.6Hz, JH2,H3
3 · OCH2Ph), 4.87 (d, JPhCH 11.2Hz, 1H, OCH2Ph),
5.09 (d, 1H, JPhCH 11.2Hz, OCH2Ph), 7.17–7.45 (m,
2
2
9.5Hz, H-2b), 3.57–3.61 (m, 1H, H-4b), 3.82 (ddd, 1H,
3
2
3
JH5,H6 0.9Hz, JH5, H6 4.5Hz, JH4,H5 9.9Hz, H-5b),
3
0
35H, Ar–H). Calcd for C62H66O11: C, 75.43; H, 6.74.
Found: C, 75.88; H, 6.83.
3
3.99 (dd, 1H, JH3,H4 9.0Hz, JH2,H3 9.5Hz, H-3a),
3
3
3
4.18 (dd, 1H, JH5,H6 1.4Hz, JH6,H6 11.2Hz, H-60b),
0
0
3
4.34 (d, 1H, JH1,H2 7.8Hz, H1-b), 4.48–5.00 (m, 14 H,
3
PhCH2), 4.60 (d, 1H, JH1,H2 3.6Hz, H-1a), 7.13–7.37
(m, 35 H, Ar–H).
4.10.7. Methyl 4-O-(2,3,4,6-tetra-O-acetyl-b-D-glucopyr-
anosyl)-2,3,6-tri-O-benzyl-a-D-glucopyranoside
Colourless syrup; Rf = 0.22 (cyclohexane/ethyl ace-
(15b).