1060
Vol. 53, No. 8
50 °C. The reaction mixture was filtered off and the filtrate was directly
chromatographed on silica gel (35 g) to give benzyl alcohol (16.9 g, 90% re-
covery) from the CHCl3 eluent and b-glucoside (1, 0.875 g, 53% yield) as
colorless solid from the CHCl3/MeOHꢀ10 : 1 eluent. The NMR (1H- and
13C-NMR) data of b-glucoside 1 were identical with those of the reported b-
glucoside 1.7,8)
A Mixtur of Benzyl 2,3,4,2ꢀ,3ꢀ,4ꢀ-O-Hexaacetyl-b-D-xylopyranosyl-
(1→6)-b-D-glucopyranoside (10) and Benzyl 2,3,6,2ꢀ,3ꢀ,4ꢀ-O-Hexaacetyl-
b-D-xylopyranosyl-(1→4)-b-D-glucopyranoside (11)
A
mixture of
8
(0.067 g, 0.168 mmol),
9
(0.109 g, 0.451 mmol), and NIS (0.120 g,
0.533 mmol) in CH2Cl2 (5 ml) was stirred for 30 min at 0 °C. To the above
mentioned mixture was added methane sulfonic acid (0.048 g, 0.50 mmol) at
0 °C and the whole mixture was stirred for 3 h at the same temperature. The
reaction mixture was filtered with the aid of celite and the filtrate was con-
densed to afford a residue, which was chromatographed on silica gel (20 g,
n-hexane/AcOEt (3 : 1)) to give a mixture (10 : 11ꢀ3 : 2, 0.044 g, 40%) as a
2) A mixture of D-glucose 5 (1.1 g, 6.1 mmol), benzyl alcohol (18.8 g,
173.9 mmol), water (2 ml), and the recovered immobilized b-glucosidase
was incubated for 4 d at 50 °C. The reaction mixture was filtered off and the
filtrate was directly chromatographed on silica gel (35 g) to give benzyl alco-
hol (17.1 g, 91% recovery) from the CHCl3 eluent and b-glucoside (1,
0.858 g, 52% yield) as colorless solid from the CHCl3/MeOHꢀ10 : 1 eluent.
Benzyl 6-O-tert-Butyldimethylsilyl-b-D-glucopyranoside (6) To a so-
lution of 1 (1.00 g, 3.70 mmol) in pyridine (30 ml) was added TBDMSCl
(1.10 g, 7.33 mmol) and 4-N,N-dimethylaminopyridine (DMAP; 10 mg,
0.08 mmol) at 0 °C, and the whole mixture was stirred for 12 h at room tem-
perature. The reaction mixture was condensed and the resulting residue di-
luted with water and extracted with AcOEt. The organic layer was washed
with 10% aqueous HCl, 7% aqueous NaHCO3, and brine. The organic layer
was dried over MgSO4 and evaporated to give a residue, which was chro-
matographed on silica gel (50 g, CHCl3/MeOH (30 : 1)) to afford 6 (1.35 g,
95%) as a colorless amorphous powder. 6: [a]D21 ꢁ58.8° (cꢀ0.873, CHCl3);
IR (KBr): 3423 (br), 3032, 2954, 2927, 2881, 2855 cmꢁ1, 1H-NMR (CDCl3):
d 0.00 (6H, s), 0.82 (9H, s), 3.13 (1H, m), 3.25—3.38 (3H, m), 3.66 (1H, dd,
Jꢀ6.0, 11.2 Hz), 3.81 (1H, dd, Jꢀ2.4, 11.2 Hz), 4.17 (1H, d, Jꢀ7.2 Hz),
4.25 (1H, br s), 4.44 (1H, br s), 4.47 (1H, d, Jꢀ11.6 Hz), 4.73 (1H, d,
Jꢀ11.6 Hz), 5.20 (1H, br s), 7.12—7.26 (5H, m); 13C-NMR (CDCl3): d
ꢁ4.77, ꢁ4.75, 18.7, 26.3 [3C], 63.9, 70.7, 71.2, 73.6, 76.1, 76.7, 101.3,
127.9, 128.4 [2C], 128.5 [2C], 137.3; Anal. Calcd for C19H32O6Si: C, 59.34;
H, 8.39%. Found: C, 58.91; H, 8.86%.
1
colorless oil. Major 10: IR (KBr): 1751 cmꢁ1, H-NMR (CDCl3): d 1.59—
2.14 (18H, m), 3.34 (1H, dd, Jꢀ8, 12 Hz), 3.64 (1H, m), 3.85 (1H, d,
Jꢀ10 Hz), 4.13 (1H, dd, Jꢀ4, 12 Hz), 4.51 (1H, d, Jꢀ8, 12.0 Hz), 4.55 (1H,
d, Jꢀ6.4 Hz), 4.63 (1H, d, Jꢀ12 Hz), 4.87—5.04 (5H, m), 5.15 (2H, m),
7.25—7.35 (5H, m); 13C-NMR (CDCl3): d 20.7, 20.7, 20.7, 20.8, 20.8, 20.8,
62.0, 67.7, 68.7, 69.0, 70.4, 70.5, 71.2, 71.3, 72.8, 73.2, 76.7, 99.0, 100.5,
127.4, 127.8, 128.3, 128.3, 136.6, 169.1, 169.1, 169.2, 169.6, 169.8, 170.0;
HR-FAB-MS (NBA) m/z: Calcd for C30H38O16Na 677.2031 (M+Na)+.
Found: 677.2058.
Benzyl b-D-Xylopyranosyl-(1→6)-b-D-glucopyranoside (2) and Benzyl
b-D-Xylopyranosyl-(1→4)-b-D-glucopyranoside (12) A mixture of the
above-mentioned mixture (10, 11, 0.026 g, 0.27 mmol) and K2CO3 (0.005 g)
in MeOH (2 ml) was stirred for 12 h at room temperature. The reaction mix-
ture was condensed to give a residue, which was chromatographed on silica
gel (10 g) to afford 2 (0.009 g, 55%) as a colorless amorphous from
CHCl3/MeOH (4 : 1) eluent and by-product 12 (0.006 g, 37%) as a colorless
amorphous from CHCl3/MeOH (4 : 1). 2: [a]D19 ꢁ48.3° (cꢀ0.76, MeOH); IR
1
(KBr): 3348 (br), 2925, 2872 cmꢁ1, H-NMR (CD3OD): d 3.09—3.41 (8H,
m), 3.68 (1H, d, Jꢀ12 Hz), 3.77 (1H, dd, Jꢀ5, 12 Hz), 4.02 (1H, d, Jꢀ10
Hz), 4.26 (2H, d, Jꢀ8 Hz), 4.56 (1H, d, Jꢀ12 Hz), 4.82 (1H, d, Jꢀ12 Hz),
7.16—7.34 (5H, m); 13C-NMR (CD3OD): d 66.9, 69.8, 71.1, 71.5, 71.9,
74.8, 75.0, 77.0, 77.7, 77.9, 103.2, 105.5, 128.5, 129.1 [2C], 129.1 [2C],
138.8; HR-FAB-MS (NBA) m/z: Calcd for C18H27O10: 403.1604 (Mꢅ1)ꢅ.
Found: 403.1579. By-product 12: [a]D19 ꢁ38.6° (cꢀ0.79, MeOH); IR (KBr):
Benzyl 2,3,4-Tri-O-acetyl-6-O-tert-butyldimethylsilyl-b-D-glucopyra-
noside (7) To a solution of 6 (1.35 g, 3.51 mmol) in pyridine (5 ml) was
added Ac2O (4 ml) and 4-N,N-dimethylaminopyridine (DMAP; 10 mg,
0.08 mmol) at 0 °C, and the whole mixture was stirred for 12 h at room tem-
perature. The reaction mixture was diluted with water and extracted with
AcOEt. The organic layer was washed with 0.5 M aqueous HCl, 7% aqueous
NaHCO3, and brine. The organic layer was dried over MgSO4 and evapo-
rated to give a residue, which was chromatographed on silica gel (50 g, n-
hexane/AcOEt (8 : 1)) to afford 7 (1.79 g, 99%) as a colorless amorphous
3348 (br), 2925, 2872 cmꢁ1 1H-NMR (CDCl3): d 3.17—3.56 (8H, m),
,
3.82—3.93 (3H, m), 4.33 (1H, d, Jꢀ8 Hz), 4.37 (1H, d, Jꢀ7.6 Hz), 4.65
(1H, d, Jꢀ12 Hz), 4.90 (1H, d, Jꢀ12 Hz), 7.24—7.41 (5H, m); 13C-NMR
(CD3OD): d 61.8, 67.1, 70.9, 71.8, 74.8, 74.9, 76.1, 76.4, 77.8, 80.8, 103.0,
105.3, 128.5, 129.0 [2C], 129.1 [2C], 138.8; HR-FAB-MS (NBA) m/z:
Calcd for C18H27O10: 403.1604 (Mꢅ1)ꢅ. Found: 403.1558.
1
powder. 7: [a]D22 ꢁ33.2° (cꢀ1.08, CHCl3); IR (KBr): 1759 cmꢁ1, H-NMR
(CDCl3): d 0.00 (6H, s), 0.83 (9H, s), 1.92 (3H, s), 1.93 (3H, s), 1.93 (3H,
s), 3.44 (1H, m), 3.64 (2H, m), 4.44 (1H, d, Jꢀ8.0 Hz), 4.55 (1H, d,
Jꢀ12.4 Hz), 4.80 (1H, d, Jꢀ12.4 Hz), 4.95 (2H, m), 5.08 (1H, t, Jꢀ9.2 Hz),
7.18—7.29 (5H, m); 13C-NMR (CDCl3): d ꢁ5.17 [2C], 18.5, 20.8, 20.8,
20.8, 25.9 [3C], 62.5, 69.1, 70.3, 71.5, 73.2, 74.8, 98.9, 127.7 [2C], 127.8,
128.3 [2C], 136.7, 169.2, 169.2, 170.2; Anal. Calcd for C25H38O9Si: C,
58.80; H, 7.50%. Found: C, 58.87; H, 7.56%.
Ethyl 2,3,4-O-Triacetyl-1-thio-a-L-rhamnopyranoside (13) To a solu-
tion of 1,2,3,4-O-tetraacetyl-a-L-rhamnopyranose (10.0 g, 30.1 mmol) in
CHCl3 (50 ml) was added ethane thiol (2.35 g, 39.1 mmol) and 47%
BF3·Et2O complex (22.4 g, 74 mmol) at 0 °C and the whole mixture was
stirred for 6 h at room temperature. The reaction mixture was diluted with
water and the organic layer was washed with 7% aqueous NaHCO3, and
brine. The organic layer was dried over MgSO4 and evaporated to give a
residue, which was chromatographed on silica gel (50 g, n-hexane/AcOEt
(5 : 1)) to afford a mixture of a- and b-isomers 13 (8.82 g, 88%). Crystal-
lization of this mixture from ether gave a isomers 13 (4.05 g, 40%) as a col-
orless needles. 13: mp 135 °C; [a]D23 ꢅ69.1° (cꢀ1.06, CHCl3); IR (KBr):
Benzyl 2,3,4-Tri-O-acetyl-b-D-glucopyranoside (8) 1) Method 1: To a
solution of 7 (2.11 g, 4.13 mmol) in MeOH (35 ml) was added 1 M IBr in
CH2Cl2 solution (6.20 g) at room temperature, and the whole mixture was
stirred for 3 h at the same temperature. The reaction mixture was diluted
with saturated sodium thiosulfate solution and extracted with CHCl3. The
organic layer was washed with brine and dried over MgSO4. Evaporation of
the organic solvent gave a residue, which was chromatographed on silica gel
(50 g, n-hexane/AcOEt (2 : 1)) to afford 8 (1.25 g, 76%) as a colorless amor-
phous powder. 8: [a]D23 ꢁ44.3° (cꢀ0.75, CHCl3); IR (KBr): 3522, 2962,
1749 cmꢁ1 1H-NMR (CDCl3): d 1.29 (3H, d, Jꢀ6 Hz), 1.99 (3H, s), 2.06
,
(3H, s), 2.16 (3H, s), 2.58—2.69 (2H, m), 4.24 (1H, m), 5.10 (1H, t,
Jꢀ10 Hz), 5.20 (1H, d, Jꢀ1.6 Hz), 5.24 (1H, dd, Jꢀ10, 3.2 Hz), 5.34 (1H,
dd, Jꢀ1.6, 3.2 Hz); 13C-NMR (CDCl3): d 14.9, 17.7, 20.6, 20.6, 20.8, 25.6,
70.4, 70.8, 71.9, 74.9, 81.9, 169.8, 170.2, 170.3; Anal. Calcd for C14H22O7S;
C, 50.29; H, 6.63%. Found: C, 50.43; H, 6.64%.
1
1734 cmꢁ1, H-NMR (CDCl3): d 1.99 (6H, s), 2.02 (3H, s), 3.51 (1H, m),
3.60 (1H, dd, Jꢀ11.6, 4.8 Hz), 3.73 (1H, d, Jꢀ11.6 Hz), 4.59 (1H, d,
Jꢀ8.0 Hz), 4.64 (1H, d, Jꢀ12.4 Hz), 4.88 (1H, d, Jꢀ12.4 Hz), 5.04 (2H, m),
5.21 (1H, t, Jꢀ9.6 Hz), 7.27—7.359 (5H, m); 13C-NMR (CDCl3): d 20.4
[2C], 20.4, 61.0, 68.5, 70.7, 71.2, 72.6, 73.9, 99.2, 127.3 [2C], 127.6, 128.0
[2C], 136.5, 168.9, 169.5, 169.8; Anal. Calcd for C19H24O9: C, 57.57; H,
6.10%. Found: C, 57.37; H, 6.12%.
2) Method 2: To a solution of 7 (0.79 g, 1.55 mmol) in MeOH (10 ml) was
added 2% I2 in MeOH solution (10 ml) at room temperature, and the whole
mixture was stirred for 4 d at the same temperature. The reaction mixture
was worked up in the same way as for method 1 to give 8 (0.55 g, 90%) as a
colorless amorphous powder.
3) Method 3: To a solution of 7 (0.015 g, 0.03 mmol) in 95% aqueous
DMSO (1.0 ml)/THF (0.5 ml)/H2O (28.5 ml) solution was added NBS
(0.003 g, 0.033 mmol) at room temperature, and the whole mixture was
stirred for 17 h at the same temperature. The reaction mixture was worked
up in the same way as for method 1 to give 8 (0.012 g, 98%) as a colorless
amorphous powder.
Benzyl 2,3,4,2ꢀ,3ꢀ,4ꢀ-O-Hexaacetyl-a-L-rhamnopyranosyl-(1→6)-b-D-
glucopyranoside (14) A mixture of 8 (0.155 g, 0.39 mmol), 13 (0.13 g,
0.39 mmol), molecular sieves 4A (0.5 g) and NIS (0.187 g, 0.83 mmol) in
CH2Cl2 (5 ml) was stirred for 30 min at 0 °C. To the above mentioned mix-
ture was added methane sulfonic acid (0.098 g, 1.02 mmol) at 0 °C and the
whole mixture was stirred for 3 h at the same temperature. The reaction mix-
ture was filtered with the aid of celite and the filtrate was condensed to af-
ford
a residue, which was chromatographed on silica gel (20 g, n-
hexane/AcOEt (3 : 1)) to give 14 (0.20 g, 76%) as a colorless amorphous
powder. 14: [a]D21 ꢁ71.5° (cꢀ1.08, CHCl3); 1H-NMR (CDCl3): d 1.22 (3H,
d, Jꢀ4.4 Hz), 2.00 (3H, s), 2.00 (3H, s), 2.01 (3H, s), 2.05 (3H, s), 2.05 (3H,
s), 2.12 (3H, s), 3.65—3.75 (3H, m), 3.85—3.93 (1H, m), 4.56 (2H, d,
Jꢀ8 Hz), 4.63 (2H, d, Jꢀ12 Hz), 4.86 (1H, d, Jꢀ0.8 Hz), 4.87 (2H, d,
Jꢀ12 Hz), 4.96 (1H, t, Jꢀ9.6 Hz), 5.04 (1H, dd, Jꢀ9.6, 8.0 Hz), 5.05—5.10
(1H, m), 5.28—5.31 (2H, m), 5.78 (1H, t, Jꢀ9.6 Hz), 7.26—7.37 (5H, m);
13C-NMR (CDCl3): d 17.2, 20.4, 20.4, 20.45, 20.5, 20.6, 20.65, 66.4, 66.7,
68.8, 69.2, 69.4, 70.4, 70.8, 71.1, 72.6, 73.3, 90.0, 99.0, 127.5 [2C], 127.7,