Benzene → 2-(Trimethylsilyl) ethyl 2,6-di-O-benzoyl-4-O-(4-O-acetyl-2,6-di-O-benzoyl-beta-D-galactopyranosyl)-3-O-(2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl)-beta-D-galactopyranoside

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Reaction Steps

A solution of compound 10a (1.87 g), in a mixture of benzene (50 mL) and triethyl orthoacetate (50 mL), containing 4-toluenesulfonic acid (0.25 g) was stirred for 1 h at room temperature. The acid was then neutralized with a few drops of triethylamine, and the mixture evaporated to dryness. The residue was mixed with 80% aqueous acetic acid (100 mL) and the mixture stirred for 40 min at room temperature. Processing as described for 10b (to give 11b), gave the title compound 11a (1.86 g,89%); a white amorphous solid; [α]D -2.7° (c, 1.1, chloroform). 13C NMR (CDCl3): δ171.03 (CH3CO), 166.78, 166.35, 166.18, 165.02 (4×PhCO), 101.27, 101.09 (C-1, C-1'), 98.17 (C-1 fuc), 80.10, 78.20 (C-3, C-4), 74.67, 73.54, 73.30 (3×PhCH2), 67.86 (OCH2CH2Si), 63.31, 61.42 (C-6, C-6'), 21.21 (CH3 CO), 18.47 (OCH2CH2Si), and 17.53 (C-6 fuc); negative ion LSIMS: 1470.8 (M+mNBA)-, 1363.7 (M+NO2)-.

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