ORDER
REPRINTS
SPACER-MODIFIED L-FUCOSE ANALOGUES
633
10-Methoxycarbonyl-6,7,8,9,10-pentadeoxy-ꢂ-L-galacto-decopyranosyl-
(1→2)-3,4-O-isopropylidene-ꢀ-D-galactopyranosyl-(1→4)-2,3;4,6-di-O-iso-
propylidene-D-glucose dimethyl acetal (34). A methanolic sodium methoxide
solution (0.5 N, 1.3 mL) was added to a solution of 33 (163 mg, 0.15 mmol) in dry
methanol (6 ml) and the mixture was stirred under an atmosphere of argon for 48
h at room temperature (TLC, solvent L, Rf 0.37). The solution was then passed
through a layer of DOWEX 50 ꢇ 4 [Hꢈ] and concentrated. The residue was puri-
fied by column chromatography (eluent solvent N) to give 34 (93 mg, 81%) as a
1
colorless syrup: [ꢂ]D23 ꢅ95.7° (c 1.0, methanol); H NMR (CD3OD) ꢄ 1.28–1.67
(m, 8H, Fuc: H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 1.30, 1.32, 1.36, 1.42,
1.45 [5s, 18H, 3 ꢇ C(CH3)2, two signals are isochronic], 2.30 (t, 2H, Fuc: H-10,
H-10ꢁ), 3.45, 3.47 [2s, 6H, C(OCH3)2], 3.64 (s, 3H, CO2CH3), 3.67 (dd, 1H, J3,4
ꢃ 3.2 Hz, Fuc: H-3), 3.69 (dd, 1H, J2,3 ꢃ 6.1 Hz, Gal: H-2), 3.71 (m, 1H, Fuc: H-
5), 3.74 (dd, 1H, J2,3 ꢃ 9.0 Hz, Fuc: H-2), 3.77 (d, 1H, Fuc: H-4), 3.83 (m, 2H, Gal:
H-6, H-6ꢁ), 3.86 (dd, 1H, J4,5 ꢃ 6.6 Hz, Glc: H-4), 3.88 (m, 1H, Gal: H-5), 4.01
(dd, 1H, J5,6 ꢃ 6.3 Hz, J6,6ꢁ ꢃ 8.4 Hz, Glc: H-6), 4.13 (dd, 1H, J5,6ꢁ ꢃ 4.8 Hz, Glc:
H-6ꢁ), 4.14 (dd, 1H, J3,4 ꢃ 1.4 Hz, Glc H-3), 4.19 (dd, 1H, J4,5 ꢃ 1.7 Hz, Gal:
H-4), 4.26 (m, 1H, Glc: H-5), 4.31 (t, 1H, J3,4 ꢃ 6.1 Hz, Gal: H-3), 4.40 (d, 1H, J1,2
ꢃ 6.4 Hz, Glc: H-1), 4.53 (dd, 1H, J2,3 ꢃ 8.1 Hz, Glc: H-2), 4.59 (d, 1H, J1,2 ꢃ 8.1
Hz, Gal: H-1), 5.35 (d, 1H, J1,2 ꢃ 3.0 Hz, Fuc: H-1); 13C NMR (CD3OD) ꢄ 25.30,
26.51, 27.15, 27.31, 27.32, 28.27, [3 ꢇ C(CH3)2], 25.99, 26.45, 30.54, 31.47 (Fuc:
C-6, C-7, C-8, C-9), 34.72 (Fuc: C-10), 51.92 (CO2CH3), 55.22, 57.29
[C(OCH3)2], 62.69 (Gal: C-6), 66.85 (Glc: C-6), 70.10 (Fuc: C-5), 71.47 (Fuc:
C-2), 71.76 (Glc: C-5), 72.10 (Gal: C-2), 75.08 (Gal: C-4), 75.36 (Fuc: C-4), 76.76,
76.82 (Fuc: C-3, Glc: C-2), 76.96 (Glc: C-4), 77.89 (Glc: C-5), 78.72 (Glc: C-3),
81.42 (Gal: C-3), 97.52 (Fuc: C-1), 102.95 (Gal: C-1), 108.23 (Glc: C-1), 110.13,
110.61, 111.33 [3 ꢇ C(CH3)2], 175.89 (CO2CH3).
Anal. Calcd for C35H60O18 (768.83): C, 54.67; H, 7.87. Found: C, 54.53;
H, 7.91.
2,3,4-Tri-O-benzyl-6,7,8,9,10-pentadeoxy-ꢂ-L-galacto-decopyranosyl-
(1→2)-4-O-ꢀ-D-galactopyranosyl-(1→4)-ꢂ/ꢀ-D-glucopyranose (35). A solution
of 32 (1.18 g, 1.2 mmol) in 30 mL aq 60% acetic acid was heated for 6 h at 60°C
(TLC, solvent L, Rf 0.19). The reaction mixture was then diluted with toluene (60
mL) and concentrated. The residue was coconcentrated with toluene (3 ꢇ 60 mL)
in order to remove traces of acetic acid. Finally, the crude product was purified by
MPLC (eluent solvent N) to yield 35 (704 mg, 72%) as a colorless syrup: Partially
interpreted 1H NMR (CD3OD) ꢄ 0.87 (m, 3H, Fuc: H-10, H-10ꢁ, H-10ꢋ), 1.16–1.59
(m, 8H, Fuc: H-6, H-6ꢁ, H-7, H-7ꢁ, H-8, H-8ꢁ, H-9, H-9ꢁ), 4.44 (d, 0.4H, J1,2 ꢃ 7.7
Hz, Glc: H-1ꢀ), 4.46 (d, 1H, J1,2 ꢃ 7.0 Hz, Gal: H-1), 5.09 (d, 0.6H, J1,2 ꢃ 3.7 Hz,
Glc: H-1ꢂ), 5.72 (d, 1H, J1,2 ꢃ 3.6 Hz, Fuc: H-1), 7.24–7.46 (m, 15H, CH2C6H5);
partially interpreted 13C NMR (CD3OD) ꢄ 14.53 (Fuc: C-10), 23.50, 23.61, 26.58,
26.76, 31.98, 32.06, 33.38, 33.51 (Fuc: C-6, C-7, C-8, C-9), 61.65, 61.90 (Glc:
C-6ꢂ, C-6ꢀ), 62.48 (Gal: C-6), 73.42, 73.99, 76.00 (3 ꢇ CH2C6H5), 70.96, 71.87,
72.14, 73.00, 73.65, 75.58, 75.91, 76.39, 76.42, 76.50, 76.92, 77.27, 77.54, 77.85,