Lowary et al.
1125
(C-6>). HR-FAB-MS calcd. for C13H24O9Na [M + Na]+:
347.1318; found: 347.1320.
OCH3), 33.715 (C-3>), 16.260 (C-6>). HR-FAB-MS calcd for
C14H26O9Na [M + Na]+: 361.1475; found: 361.1480.
Methyl 4,6-di-O-benzyl-3-O-(2,4-di-O-benzyl-3,6-
dideoxy-ꢂ-D-xylo-hexopyranosyl)-2-O-methyl-ꢂ-D-
talopyranoside (36)
Methyl 4,6-di-O-benzyl-3-O-(2,4-di-O-benzyl-3,6-
dideoxy-ꢂ-D-xylo-hexopyranosyl)-2-O-(2,3,4,6-tetra-O-
benzyl-ꢂ-D-galactopyranosyl)-ꢂ-D-talopyranoside (38)
Disaccharide 35 (170 mg, 0.25 mmol) and thioglycoside
37 (39) (297 mg, 0.51 mmol) were dried with crushed 4 Å
molecular sieves (500 mg) over P2O5 under vacuum over-
night. The solids were suspended in CH2Cl2 (10 mL) and
cooled to 0°C. N-Iodosuccinimide (124 mg, 0.55 mmol) and
silver triflate (14 mg, 0.055 mmol) were then added. After
stirring for 40 min and warming to room temperature, the re-
action was quenched with triethylamine. Dilution with
CH2Cl2 was followed by washing with a saturated solution
of sodium thiosulfate, water, and a saturated solution of
NaCl. After drying (Na2SO4) and evaporation of the solvent,
chromatography (toluene–EtOAc, 9:1) gave the product 38
(106 mg, 35%) as an oil. [ꢂ]D +58.8 (c 0.9, CHCl3). Rf =
Alcohol 35 (136 mg, 0.20 mmol) was dissolved in DMF
(5 mL) and cooled to 0°C. Sodium hydride (18.0 mg, 80%
dispersion in oil, 0.6 mmol) was added and the mixture
stirred for 10 min. To this solution was added methyl iodide
(20 L, 0.60 mmol) and the reaction stirred overnight while
being allowed to warm to room temperature. Upon quench-
ing the reaction with CH3OH, the solution was partitioned
between water with CH2Cl2. The organic layer was then
washed with water, a saturated solution of NaCl, dried
(Na2SO4), and evaporated. Chromatography (pentane–
EtOAc, 3:1) gave 36 (124 mg, 90%) as an oil. [ꢂ]D +49.5
1
(c 1.0, CHCl3). Rf = 0.25 (pentane–EtOAc, 3:1). H NMR
(CDCl3) ꢄ: 7.15–7.40 (m, 20H, Ph), 5.09 (d, J1>,2> = 3.5 Hz,
2
1
1H, H-1>), 4.92 (d, J = 12.0 Hz, 1H, PhCH2), 4.83 (d, J1,2
=
0.31 (toluene–EtOAc, 9:1). H NMR (CDCl3) ꢄ: 7.10–7.40
2
2
2.0 Hz, 1H, H-1), 4.68, 4.63 (d, J = 12.0 Hz, 1H, PhCH2),
4.31–4.58 (m, 6H, PhCH2), 4.23 (q, 1H, H-5>), 3.75–4.10
(m, 40H, Ph), 5.38 (d, J = 12.0 Hz, 1H, PhCH2), 5.16 (d,
J1,2 = 2.0 Hz, 1H, H-1), 5.06 (d, J1>,2> = 3.5 Hz, 1H, H-1>),
5.02 (d, J1 >>,2 >> = 3.5 Hz, 1H, H-1>>), 4.83, 4.80 (d, J =
2
(m, 5H, H-3, H-4, H-5, H-6a, H-2>), 3.58 (dd, J6a,6b
=
10.5 Hz, J5,6b = 5.0 Hz, 1H, H-6b), 3.53 (s, 3H, OCH3), 3.48
(br. s, 1H, H-4>), 3.38–3.45 (m, 4H, OCH3, H-2), 2.18 (dt,
J2,3>eq W J3>eq,4 = 3.5 Hz, J3>eq,3>ax = 13.0 Hz, 1H, H-3>eq),
1.92 (dt, J3>ax,4 = 13.0 Hz, J2 >,3 >ax = 2.5 Hz, 1H, H-3>ax),
1.23 (d, J5>6> = 6.5 Hz, 3H, H-6>). 13C NMR (CDCl3) ꢄ: 98.31
(C-1), 98.07 (C-1>), 73.90, 73.39, 71.28, 70.95 (PhCH2),
69.30 (C-6), 59.19 (OCH3), 55.18 (OCH3), 27.73 (C-3>),
16.66 (C-6>). Anal. calcd. for C42H50O9 (698.86): C 72.19,
H 7.21; found: C 71.73, H 7.40.
12.0 Hz, 1H, PhCH2), 4.40–4.65 (m, 13H, PhCH2), 4.23 (d,
2J = 12.0 Hz, 1H, PhCH2), 3.54–4.15 (m, 14H, H-3, H-4,
H-5, H-6a, H-6b, H-2>, H-5>, H-2>>, H-3>>, H-4>>, H-5>>,
H-6a>>, H-6b>>), 3.26 (s, 3H, OCH3), 2.63 (br. s, 1H, H-4>),
1.90 (dt, J2>,3>eq, J3>eq,4> = 3.5 Hz, J3>eq,3>ax = 13.0 Hz, 1H,
H-3>eq), 1.77 (dt, J3>ax,4 = 13.0 Hz, J2>,3ax = 2.5 Hz, 1H,
H-3>ax), 1.06 (d, J5>6> = 6.5 Hz, 3H, H-6>). 13C NMR
(CDCl3) ꢄ: 100.26 (C-1>>), 99.93 (C-1), 99.01 (C-1>), 69.20
(C-6), 66.41 (C-1>>), 54.91 (OCH3), 27.75 (C-3>), 16.46
(C-6>). Anal. calcd. for C75H82O14 (1207.47): C 74.60, H 6.84;
found: C 74.81, H 7.29.
Methyl 3-O-(3,6-dideoxy-ꢂ-D-xylo-hexopyranosyl)-2-O-
methyl-ꢂ-D-talopyranoside (12)
Methyl 3-O-(3,6-dideoxy-ꢂ-D-xylo-hexopyranosyl)-2-O-(ꢂ-
D-galactopyranosyl)-ꢂ-D-talopyranoside (13)
Methyl ether 36 (118 mg, 0.17 mmol) was dissolved in
acetic acid (5 mL) and then 10% Pd/C (100 mg) was added.
The reaction was stirred overnight under a flow of H2. After
filtration of the catalyst and evaporation of the solvent the
residue was subjected to chromatography (CH2Cl2–CH3OH,
9:1) on Iatrobeads. The product obtained was then
redissolved in water, filtered through a 0.22 M filter and
lyophilized to give the product 12 (45 mg, 78%) as an amor-
The protected trisaccharide 38 (78 mg, 0.06 mmol) was
dissolved in acetic acid (5 mL) and then 10% Pd/C (100 mg)
was added. The reaction was stirred overnight under a flow
of H2. After filtration of the catalyst and evaporation of the
solvent, the residue was subjected to chromatography
(CH2Cl2–CH3OH–water, 65:35:5) on Iatrobeads. The prod-
uct obtained was then redissolved in water, filtered through a
0.22 M filter and lyophilized to give 13 (26 mg, 86%) as an
amorphous white solid. [ꢂ]D +176.8 (c 0.5, H2O). Rf = 0.58
phous white solid. Rf = 0.55 (CH2Cl2–CH3OH, 4:1). [ꢂ]D
1
+143.4 (c 0.5, H2O). H NMR (D2O) ꢄ: 5.045 (d, J1,2
=
1.5 Hz, 1H, H-1), 5.021 (d, J1>,2> = 4.0 Hz, 1H, H-1>), 4.069
(dq, J4>,5> = 1.5 Hz, J5>,6> = 7.0 Hz, 1H, H-5>), 4.035 (dd, J3,4
3.0 Hz, J4,5 = 1.0 Hz, 1H, H-4), 4.015 (ddd, J1>,2> = 4.0 Hz,
J2>,3>ax = 13.0 Hz, J2>,3>eq = 5.0 Hz, 1H, H-2>), 3.957 (t, J2,3
1
=
(CH2Cl2–CH3OH–water, 65:35:5). H NMR (D2O) ꢄ: 5.304
(d, J1>,2> = 3.5 Hz, 1H, H-1>), 5.060 (d, J1 >>,2 >> = 4.0 Hz,
1H, H-1>>), 5.056 (s, 1H, H-1), 4.01–4.15 (m, 6H, H-2, H-3,
H-4, H-2>, H-5>, H-5>>), 3.980 (d, J3 >>,4 >> = 3.5 Hz, 1H,
H-4>>), 3.919 (dd, J3 >>,4 >> = 3.5 Hz, 1H, H-3>>), 3.85–3.90
(m, 3H, H-5, H-6a, H-4>), 3.826 (dd, J2 >>,3 >> = 10.0 Hz, 1H,
H-2>>), 3.750 (d, J5 >>,6 >> = 6.0 Hz, 1H, H-6>>), 3.428 (s, 3H,
=
3.0 Hz, J3,4 = 3.0 Hz, 1H, H-3), 3.86–3.90 (m, 2H, 4–5, H-4>),
3.825 (dd, J5,6a = 8.0 Hz, J6a,6b = 11.5 Hz, 1H, H-6a), 3.752
(dd, J5,6b = 4.0 Hz, J6a,6b = 11.5 Hz, 1H, H-6b), 3.486 (s, 3H,
aglycon OCH3), 3.441 (ether OCH3), 2.088 (dt, J2>,3>ax
13.0 Hz, J3>ax,3>eq = 13.0 Hz, J3>ax,4> = 3.0 Hz, 1H, H-3>ax),
1.998 (ddd, J2>,3>eq = 5.0 Hz, J3>ax,3>eq = 13.0 Hz, J3>eq,4>
=
OCH3), 2.00–2.02 (m, 2H, H-3>ax, H-3>eq), 1.176 (d, J5>,6>
=
=
=
6.5 Hz, 3H, H-6>). 13C NMR (D2O) ꢄ: 101.618 (C-1>>, 1JC,H
1
4.0 Hz, 1H, H-3>eq), 1.184 (d, J5>,6> = 7.0 Hz, 3H, H-6>).
173.7 Hz), 100.858 (C-1, JC,H = 174.2 Hz), 95.856 (C-1>,
1JC,H = 169.9 Hz), 79.936 (C-2), 72.422 (C-5>>), 72.052
(C-5), 70.944 (C-3), 70.136 (C-4>>), 70.038 (C-3>>), 69.260
(C-2>>), 69.171 (C-4>), 67.911 (C-5), 66.372 (C-4), 63.992
(C-2>), 62.240 (2 C, C-6, C-6>>), 55.626 (OCH3), 33.896
13C NMR (D2O) ꢄ: 98.530 (C-1, JC,H = 170.7 Hz), 97.895
1
1
(C-1>, JC,H = 168.6 Hz), 79.796 (C-2), 72.525 (C-3), 72.324
(C-5), 69.217 (C-4>), 67.773 (C-5>), 67.309 (C-4), 64.056
(C-2>), 62.264 (C-6), 59.319 (ether OCH3), 55.675 (aglycon
© 2002 NRC Canada