´
F. Chevalier, J. Angulo, R. Lucas, P. M. Nieto, M. Martın-Lomas
FULL PAPER
Methyl [Dimethylthexylsilyl 4-O-(6-O-acetyl-2-azido-3,4-di-O-
benzyl-2-deoxy-α-D-glucopyranosyl)-2-O-benzoyl-3-O-benzyl-β-L-
idopyranosyl] Uronate (5): TMSOTf (39 µL, 0.216 mmol) was ad-
ded under argon to a cooled (0 °C) solution of 3 (1.90 g,
4.32 mmol) in dry CH2Cl2 (100 mL). While the reaction mixture
Trichloroacetimidate (7):[13] Cl3CCN (593 µL, 5.90 mmol) and
K2CO3 (55 mg, 0.39 mmol) were added to a solution of 6 (320 mg,
0.39 mmol) in dry CH2Cl2 (4 mL). After stirring at room temp. for
4 h, the mixture was filtered off and concentrated in vacuo, and the
residue was purified on a short silica gel column [hexane/ethyl acet-
was stirred, a solution of 4 (2.48 g, 4.32 mmol) in dry CH2Cl2 ate (2:1)] to yield 6 (357 mg, 95%) as an α/β mixture. TLC [hexane/
(25 mL) was added dropwise. After 30 min, the mixture was neut-
ethyl acetate (2:1)]: Rf ϭ 0.53 and 0.38 (β and α). 1H NMR
ralised with saturated NaHCO3 solution, and CH2Cl2 (400 mL) (500 MHz, CDCl3): δ ϭ 8.67 (s, 0.6 H, NHβ), 8.64 (s, 0.4 H, NHα),
was then added at room temp. The suspension was washed with
H2O (250 mL). The organic layer was dried with MgSO4 and con-
centrated under vacuum, the residue was purified by flash chroma-
tography (12:1, toluene/ethyl acetate) to obtain unchanged acceptor
(363 mg, 19%), and the disaccharide was directly dissolved in Py
(15 mL). Benzoyl chloride (4.1 mL, 35.21 mmol) was added, and
8.13Ϫ7.10 (m, 20 H, Ph), 6.55 (br. s, 0.6 H, H1β), 6.29 (d, 0.4 H,
J1,2 ϭ 1.8 Hz, H1α), 5.43 (m, 0.4 H, H2α), 5.33 (br. s, 0.6 H, H2β),
5.00 (br. s, 0.4 H, H5α), 4.93Ϫ4.88 (m, 1 H, 1ϫ CH2Ph), 4.79Ϫ4.65
(m, 3.6 H, H5β, H1Ј, 1ϫ CH2Ph), 4.52Ϫ4.46 (m, 1 H, 1ϫ CH2Ph),
4.38Ϫ4.35 (m, 1.4 H, H6Јa, H3α), 4.25Ϫ4.23 (m, 1.6 H, H6Јb, H3β),
4.15 (br. s, 0.4 H, H4α), 4.03Ϫ3.88 (m, 3.6 H, H5Ј, H4β, CH2Ph),
the solution was stirred at room temp. After 24 h, the mixture was 3.79Ϫ3.78 (2 s, 3 H, COOCH3 α and β), 3.51Ϫ3.41 (m, 2 H, H3Ј,
diluted with CH2Cl2 (400 mL), washed with H2O (300 mL), dried
with MgSO4, and concentrated under vacuum. The residue was
purified by flash chromatography [toluene/ethyl acetate (12:1)] to
yield 5 (2.115 g, 51%). [α]rD.t. ϭ ϩ18.0 (c ϭ 1, CHCl3); TLC [toluene/
H4Ј), 3.23Ϫ3.19 (m, 1 H, H2Ј), 1.99 (s, 3 H, OCOCH3 α and β)
ppm. C45H45Cl3N4O13 (956.2): calcd. C 56.52, H 4.74, N 5.86;
found C 56.17, H 4.98, N 5.79.
1
Methyl [Isopropyl 4-O-(6-O-acetyl-2-azido-3,4-di-O-benzyl-2-deoxy-
α-D-glucopyranosyl)-2-O-benzoyl-3-O-benzyl-α-L-idopyranosyl]
ethyl acetate (12:1)]: Rf ϭ 0.26. H NMR (500 MHz, CDCl3): δ ϭ
8.11Ϫ7.22 (m, 20 H, Ph), 5.17 (br. s, 1 H, H1), 5.07 (br. s, 1 H,
H2), 4.84Ϫ4.74 (2 d, Jgem ϭ 11.7 Hz, 2 H, CH2Ph), 4.72 (d, J1Ј,2Ј
ϭ
Uronate (8): Isopropyl alcohol (46 µL, 0.75 mmol) and TMSOTf
(50 µL of a 0.18 solution in dry CH2Cl2) were added under argon
to a cooled (0 °C) solution of 7 (242 mg, 0.25 mmol) in dry CH2Cl2
(3 mL). After 5 min, the mixture was neutralised with saturated
NaHCO3 solution and diluted with CH2Cl2 (100 mL). The suspen-
sion was washed with H2O (100 mL), and the organic layer was
dried (MgSO4) and concentrated in vacuo. The residue was purified
by flash chromatography [hexane/ethyl acetate (6:1)] to yield the α
3.4 Hz, 1 H, H1Ј), 4.67Ϫ4.49 (2 d, Jgem ϭ 10.7 Hz, 2 H, CH2Ph),
4.48 (br. s, 1 H, H5), 4.38 (dd, J5Ј,6Јa ϭ 1.8 Hz, J6Јa,6Јb ϭ 12.4 Hz,
1 H, H6Јa), 4.30 (dd, J5Ј,6Јb ϭ 2.3 Hz, 1 H, H6Јb), 4.23 (m, 1 H, H3),
4.07 (m, 1 H, H5Ј), 4.01 (br. s, 1 H, H4), 3.96Ϫ3.87 (2d, Jgem
ϭ
10.7 Hz, 2 H, CH2Ph), 3.75 (s, 3 H, COOCH3), 3.53Ϫ3.43 (m, 2
H, H3Ј, H4Ј), 3.12 (dd, J2,3 ϭ 10.1 Hz, 1 H, H2Ј), 1.99 (s, 3 H,
OCOCH3), 1.56 [m, 1 H, CH(CH3)2], 0.79Ϫ0.75 [4 s, 12 H,
C(CH3)2, CH(CH3)2], 0.25Ϫ0.13 [2 s, 6 H, Si(CH3)2] ppm. 13C
NMR (125 MHz, CDCl3): δ ϭ 170.6, 168.6, 166.5 (CϭO),
137.8Ϫ127.7 (Ph), 99.6 (C1Ј), 93.9 (C1), 79.8, 77.3, 75.6, 75.0, 74.8,
74.6, 73.4, 73.0, 70.0, 68.7, 63.72, 62.29, 52.2 (COOCH3), 33.9
[CH(CH3)2], 24.7 [C(CH3)2], 20.8 (OCOCH3), 20.1Ϫ18.3 [C(CH3)2
and CH(CH3)2], Ϫ1.9, Ϫ3.3 [Si(CH3)2] ppm. MS-FAB: m/z ϭ 976
[M ϩ Naϩ]. C51H63N3O13Si (954.2): calcd. C 64.20, H 6.66, N 4.40;
found C 64.47, H 6.64, N 4.24.
anomer 7 (140 mg, 65%) and the β anomer (50 mg, 23%): [α]rD.t.
ϭ
ϩ22.5 (c ϭ 1.1, CHCl3). TLC [hexane/EA (3:1)]: Rf ϭ 0.37. 1H
NMR (500 MHz, CDCl3): δ ϭ 8.25Ϫ7.20 (m, 20 H, Ph), 5.28 (s, 1
H, H1), 5.12(s, 1 H, H2), 4.97 (d, 1 H, 1ϫ CH2Ph), 4.89 (d, J5,4
ϭ
2.5 Hz, 1 H, H5), 4.77 (d, J1Ј,2Ј ϭ 3.5 Hz, 1 H, H1Ј), 4.72 (m, 2 H,
CH2Ph), 4.37 (d, 1 H, 1ϫ CH2Ph), 4.36 (dd, J5Ј,6Јa ϭ 2 Hz,
J6Јa,6Јb ϭ 12.5 Hz, 1 H, H6Јa), 4.26 (dd, J5Ј,6Јa ϭ 3 Hz, J6Јa,6Јb
ϭ
12.0 Hz, 1 H, H6Јb), 4.14 (t, J3,2 ϭ J3,4 ϭ 2.5 Hz, 1 H, H3), 4.09
(m, 2 H, H4, 1ϫ CH2Ph), 4.00 [m, 3 H, 1ϫ CH2Ph, H5Ј,
CH(CH3)2], 3.77 (s, 3 H, COOCH3), 3.55 (t, 1 H, H3Ј), 3.45 (t,
Methyl
glucopyranosyl)-2-O-benzoyl-3-O-benzyl-α,β-
(6): An excess of (HF)n·Py complex (3.1 mL) was added to a cooled
(Ϫ10 °C) solution of 5 (1.067 g, 1.116 mmol) in dry THF (30 mL). CH(CH3)2] ppm. 13C NMR (125 MHz, CDCl3): δ ϭ 170.63,
The mixture was then allowed to warm to 0 °C and stirred under
169.90, 165.61 (CϭO), 137.00Ϫ127.0 (Ph), 99.62 (C1), 97.29 (C1Ј),
argon. After 24 h, CH2Cl2 (200 mL) was added, and the mixture 80.15 (C3Ј), 76.36 (C4Ј), 74.86, 74.74 (CH2Ph), 73.38 (C4), 72.16
was washed with H2O (2 ϫ 100 mL) and saturated NaHCO3 solu-
(C3), 70.48 (C5), 70.08 (CH2Ph), 68.27(C2), 67.46 (C5Ј), 63.73 (C6Ј),
4-O-(6-O-Acetyl-2-azido-3,4-di-O-benzyl-2-deoxy-α-
D-
L
-idopyranosuronate
J4Ј,3Ј ϭ J4Ј,5Ј ϭ 10 Hz, 1 H, H4Ј), 3.19 (dd, J2Ј,3Ј ϭ 3.5 Hz, J2,3
ϭ
10.0 Hz, 1 H, H2Ј), 2.05(s, 3 H, OCOCH3), 1.25Ϫ1.15 [m, 6 H,
tion (50 mL) until neutralisation. The organic layer was finally 62.38 (C2Ј), 52.39 (COOCH3), 23.35 (OCOCH3) 21.47, 20.91
dried (MgSO4) and concentrated in vacuo. Purification of the res-
idue by flash chromatography [hexane/EA (2:1)] gave 5 (800 mg,
88%) as a α/β mixture. TLC [hexane/ethyl acetate (2:1)]: Rf ϭ 0.25.
1H NMR (500 MHz, CDCl3): δ ϭ 8.14Ϫ7.06 (m, 20 H, Ph), 5.45
(br. d, J1α,OH ϭ 8.4 Hz, 0.5 H, H1α), 5.21 (br. d, J1β,OH ϭ 9.0 Hz,
0.5 H, H1β), 5.06 (br. s, 1 H, H2 α and β), 4.91 (br. s, 0.5 H, H5α),
4.91Ϫ4.85 (m, 1 H, CH2Ph), 4.80Ϫ4.74 (2 d, Jgemϭ 11.5 Hz, J ϭ
11.7 Hz, 1 H, CH2Ph), 4.66Ϫ4.62 (m, 2 H, H1Ј,CH2Ph), 4.59 (br.
s, 0.5 H, H5β), 4.47 (m, 1 H, CH2Ph), 4.37 (m, 1 H, H6Јa), 4.31 (m,
1 H, H3), 4.25Ϫ4.19 (m, 1.5 H, H6Јb, OHα), 4.01Ϫ3.82 (m, 4 H,
H5Ј, H4, CH2Ph), 3.64 (m, 0.5 H, OHβ), 3.79 (s, 3 H, COOCH3 α
[CH(CH3)2] ppm. MALDI-TOF MS: m/z ϭ 876 [M ϩ Naϩ], 892
[M ϩ Kϩ]. C46H51N3O13 (853.9): calcd. C 64.77, H 5.97, N 4.92;
found C 64.06, H 6.12; N 5.04.
Isopropyl 4-O-(2-Azido-3,4-di-O-benzyl-2-deoxy-α-
D-gluco-
pyranosyl)-3-O-benzyl-α- -idopyranosiduronic Acid Sodium Salt (9):
L
A solution of 8 (84 mg, 0.09 mmol) in THF (9.2 mL) was treated
at 0 °C with hydrogen peroxide (30 wt% solution in water, 1.8 mL)
and LiOH (1.0 , 2.35 mL), and the mixture was stirred for 6 h at
room temp. and was then cooled to 0 °C. MeOH (7.0 mL) and
NaOH (4 , 2.35 mL) were then added, and the mixture was stirred
for 16 h and was treated with Amberlite IR-120 (Hϩ) resin until
neutralisation, filtered, and concentrated under reduced pressure.
The residue was eluted through Sephadex LH-20 chromatography
column with CH2Cl2/MeOH (1:1) to afford 8 (60.4 mg, 89%).
[α]rD.t. ϭ Ϫ0.6 (c ϭ 0.5, MeOH). TLC [CH2Cl2/MeOH (10:1)]: Rf ϭ
0.46. 1H NMR (500 MHz, [D4]methanol): δ ϭ 7.38Ϫ7.12 (m, 15
and β), 3.41 (m, 2 H, H3Ј, H4Ј), 3.19 (dd, J1,2 ϭ 3.7 Hz, J2,3
ϭ
9.2 Hz, 1 H, H2Ј), 2.00 (s, 3 H, OCOCH3 α and β) ppm. MS-FAB:
m/z ϭ 834 [M ϩ Naϩ]. C43H45N3O13 (811.8): calcd. C 63.62, H
5.59, N 5.18; found C 63.22, H 5.95, N 4.94.
O-[Methyl 4-O-(6-O-acetyl-2-azido-3,4-di-O-benzyl-2-deoxy-α-D-
glucopyranosyl)-2-O-benzoyl-3-O-benzyl-α,β-
L
-idopyranosyluronate] H, Ph), 5.30 (s, 1 H, H1), 5.03(s, 1 H, H1Ј), 1.12 [m, 6 H,
2374
Eur. J. Org. Chem. 2002, 2367Ϫ2376