V. Subramaniam et al. / Bioorg. Med. Chem. 13(2005) 1083–1094
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up. Rf 0.41 (4:1 hexane–EtOAc); [a]D +47.7 (c 1.0,
CHCl3); 1H NMR (400 MHz, CDCl3): dH 7.11–7.37
(m, 30H), 5.14 (d, 1H, J = 1.4 Hz), 4.86 (d, 2H,
J = 10.9 Hz), 4.80 (d, 1H, J = 1.4 Hz), 4.73 (ABq, 2H,
J = 12.3 Hz, Dt = 28.7 Hz), 4.55–4.68 (m, 6H), 4.46
(dd, 1H, J = 1.4, 2.0 Hz), 4.43–4.44 (m, 2H), 3.59–3.94
(m, 12H), 3.42 (s, 3H), 3.32 (dt, 1H, J = 6.5, 9.6 Hz),
1.48–1.49 (m, 2H), 1.26–1.29 (m, 10H), 0.88 (t, 3H,
J = 7.0 Hz); 13C NMR (125.8 MHz, CDCl3): dC 139.2,
139.0, 139.0, 138.9, 138.9, 138.7, 128.8, 128.8, 128.7,
128.6, 128.5, 128.3, 128.3, 128.2, 128.1, 128.0, 128.0,
127.8, 98.3, 98.0, 80.9, 79.6, 75.7, 75.6, 75.5, 75.2, 75.0,
73.8, 73.4, 72.7, 72.2, 72.1, 72.0, 69.6, 68.0, 66.5, 59.3,
32.3, 29.9, 29.9, 29.7, 29.6, 23.1, 14.6. HR-MALDI-
MS calcd for C63H76O11 [M+Na]+ 1031.5285, found
1031.5265.
fied chromatography (4:1 hexane–EtOAc) on Iatrobeads
to give 18 (160 mg, 61%). Rf 0.31 (4:1 hexane–EtOAc);
[a]D +52.2 (c 0.8, CHCl3); 1H NMR (500 MHz, CDCl3):
d
H 7.14–7.37 (m, 30H), 5.12 (d, 1H, J = 3.4 Hz), 4.93 (d,
1H, J = 11.2 Hz), 4.88 (d, 1H, J = 11.0 Hz,), 4.81 (d, 1H,
J = 1.2 Hz), 4.71 (ABq, 2H, J = 12.4 Hz, Dt = 31.9 Hz),
4.53–4.68 (m, 6H), 4.48 (d, 1H, J = 11.0 Hz), 4.43 (d,
1H, J = 12.1 Hz), 3.90–4.00 (m, 3H), 3.87 (dd, 1H,
J = 4.6, 11.3 Hz), 3.76–3.78 (m, 1H), 3.74–3.75 (m,
1H), 3.70 (dd, 1H, J = 4.4, 10.4 Hz), 3.57–3.67 (m,
4H), 3.55 (dd, 1H, J = 1.6, 10.4 Hz), 3.32 (dt, 1H,
J = 6.5, 9.7 Hz), 2.37 (dd, 1H, J = 4.9, 10.4 Hz), 1.68
(ddd, 1H, J = 12.7, 12.7, 3.4 Hz), 1.49–1.51 (m, 2H),
1.26–1.30 (m, 10H), 0.87 (t, 3H, J = 7.2 Hz);
13C NMR (125.8 MHz, CDCl3): dC 139.2, 139.1,
139.0, 138.6, 128.8, 128.8, 128.7, 128.4, 128.2,
128.2, 128.2, 128.1, 128.1, 128.0, 128.0, 127.9, 127.9,
98.2, 98.1, 80.9, 78.7, 75.6, 75.5, 75.4, 75.3, 75.3, 73.9,
73.1, 72.6, 72.0, 72.0, 71.3, 69.3, 68.1, 66.4, 35.7,
32.3, 29.9, 29.9, 29.7, 26.6, 23.1, 14.6. HR-MALDI-
MS calcd for C62H74O10 [M+Na]+ 1001.5180, found
1001.5177.
3.13. Octyl 3,4,6-tri-O-benzyl-2-O-(methylthio)thiocar-
bonyl-a-D-mannopyranosyl-(1!6)-2,3,4-tri-O-benzyl-a-
D-mannopyranoside (17)
Disaccharide 15 (300 mg, 0.30 mmol) was dissolved in
THF (20 mL), and then sodium hydride (44 mg,
1.83 mmol) was added along with a catalytic amount
of imidazole (10 mg). The mixture was stirred for 1 h,
before carbon disulfide (230 mL, 3.9 mmol) was added
and the stirring continued for an additional hour.
Methyl iodide (132 mL, 2.12 mmol) was then added
and the reaction mixture was stirred for 12 h. The sol-
vent was evaporated and the residue was dissolved in
CH2Cl2 (25 mL), and washed with water (20 mL). The
organic layer was dried (Na2SO4), filtered, and concen-
trated to a yellow syrup, which was purified by chroma-
tography (4:1 hexane–EtOAc) on silica gel to give 17
(324 mg, 99%) as a lightyellow syrup. Rf 0.46 (4:1 hex-
ane–EtOAc); [a]D +26.7 (c 1.7, CHCl3); 1H NMR
(400 MHz, CDCl3): dH 7.16–7.38 (m, 30H), 6.26 (dd,
1H, J = 2.0, 2.0 Hz), 5.11 (d, 1H, J = 2.0 Hz), 4.91
(d, 1H, J = 11.1 Hz), 4.87 (d, 1H, J = 10.9 Hz), 4.80
(d, 1H, J = 1.5 Hz), 4.61–4.71 (m, 6H), 4.42–4.52 (m,
4H), 4.09 (dd, 1H, J = 3.0, 9.3 Hz), 3.98 (dd, 1H,
J = 9.6, 9.6 Hz), 3.86–3.91 (m, 3H), 3.83 (dd, 1H, J =
1.5, 1.5 Hz), 3.73–3.77 (m, 4H), 3.65 (dd, 1H, J = 1.4,
9.2 Hz), 3.60 (dt, 1H, J = 6.8, 9.7 Hz), 3.31 (dt, 1H,
J = 6.8, 9.7 Hz), 2.48 (s, 3H), 1.47–1.50 (m, 2H), 1.26–
1.29 (m, 10H), 0.88 (t, 3H, J = 6.4 Hz); 13C NMR
(125.8 MHz, CDCl3): dC 215.5, 139.0, 139.0, 138.8,
128.8, 128.8, 128.7, 128.6, 128.3, 128.3, 128.3, 128.2,
128.1, 128.1, 128.1, 128.0, 98.1, 97.3, 80.9, 78.3, 77.2,
75.6, 75.5, 75.4, 75.2, 75.0, 73.9, 73.1, 72.5, 72.1, 72.0,
71.5, 69.3, 68.2, 67.1, 32.3, 29.9, 29.9, 29.8, 26.7, 23.2,
19.1, 14.6. HR-MALDI-MS calcd for C64H76O11S2
[M+Na]+ 1107.4727, found 1107.4630.
3.15. Octyl 3,4,6-tri-O-acetyl-2-deoxy-2-fluoro-a-D-
mannopyranosyl-(1!6)-2,3,4-tri-O-benzyl-a-D-manno-
pyranoside (20)
Trichloroacetimidate 1945 (216 mg, 0.48 mmol) and
alcohol 12 (223 mg, 0.40 mmol) were dried in vacuo with
˚
powdered 4 A molecular sieves (300 mg) overnight. Dry
CH2Cl2 (8 mL) was added and the mixture was cooled
to ꢀ10 ꢁC with stirring. A solution of TMSOTf
(200 lL) in CH2Cl2 (1.25 mL) was added dropwise to
the reaction mixture and the stirring was continued for
2 h, while warming to 0 ꢁC. The solution was neutralized
by the addition of a saturated NaHCO3 solution (3 mL)
and then, CH2Cl2 (30 mL) was added. The organic layer
was washed with water (20 mL), dried (Na2SO4), fil-
tered, and concentrated to a colorless syrup, which
was purified by chromatography (4:1 hexane–EtOAc)
on silica gel to give 20 (302 mg, 89%) as a colorless syr-
up. Rf 0.44 (4:1 hexane–EtOAc); [a]D +58.6 (c 1.3,
CHCl3); 1H NMR (500 MHz, CDCl3): dH 7.25–7.36
(m, 15H), 5.31 (dd, 1H, J = 9.9, 9.9 Hz), 5.27 (ddd,
1H, J = 2.0, 29.5, 9.9 Hz), 5.22 (dd, 1H, J = 2.0,
7.5 Hz), 4.98 (d, 1H, J = 11.2 Hz), 4.76 (ddd, 1H,
J = 2.0, 2.0, 49.7 Hz), 4.75–4.79 (m, 2H), 4.60–4.66 (m,
4H), 4.19 (dd, 1H, J = 4.6, 12.3 Hz), 4.11 (dd, 1H,
J = 2.1, 12.3 Hz), 4.01–4.03 (m, 1H), 3.90–3.92 (m,
3H), 3.88 (dd, 1H, J = 4.7, 11.4 Hz), 3.79 (dd, 1H,
J = 1.0, 11.4 Hz), 3.69–3.71 (m, 1H), 3.60 (dt, 1H,
J = 6.7, 9.7 Hz), 3.33 (dt, 1H, J = 6.5, 9.7 Hz), 2.05 (s,
3H), 2.03 (s, 3H), 2.02 (s, 3H), 1.50–1.53 (m, 2H),
1.27–1.32 (m, 10H), 0.88 (t, 3H, J = 7.0 Hz); 13C
NMR (125.8 MHz, CDCl3): dC 171.2, 170.2, 170.0,
138.9, 138.8, 138.8, 128.8, 128.8, 128.8, 128.3, 128.1,
128.1, 128.1, 128.0, 98.2, 97.8 (d, J = 29.0 Hz), 87.4 (d,
J = 179.5 Hz), 80.8, 75.5, 74.8, 73.3, 72.6, 72.2, 70.3,
70.1 (d, J = 16.4 Hz), 68.9, 68.2, 67.2, 66.4, 62.5, 32.3,
29.8, 29.8, 29.7, 26.6, 23.1, 21.2, 21.1, 21.1, 14.5; 19F
NMR (235.4 MHz, CDCl3): dF ꢀ203.2 (ddd, 1F,
J = 7.5, 49.7, 29.5 Hz). HR-MALDI-MS calcd for
C47H61O13F [M+Na]+ 875.3994, found 875.4004.
3.14. Octyl 3,4,6-tri-O-benzyl-2-deoxy-a-D-arabino-
hexopyranosyl-(1!6)-2,3,4-tri-O-benzyl-a-D-mannopy-
ranoside (18)
Xanthate 17 (296 mg, 0.27 mmol) was dissolved in dry
toluene (50 mL), and tri-n-butylstannane (1.1 mL,
4.05 mmol) and AIBN (36 mg, 0.22 mmol) were added.
The reaction mixture was heated at reflux for 2 h and
the solvent was evaporated. The crude syrup was puri-