Citric Acid → 1-(beta-D-glucopyranosyl)-3-(5-(6-fluoro-3-pyridyl)-2-thienyl-methyl)-4-methylbenzene

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Reaction Steps

A solution of the above 1-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-3-(5-chloro-2-thienylmethyl)-4-methylbenzene 57 (200 mg), 6-fluoropyridine-3-boronic acid 58 (117 mg), tri-tert-butylphosphine•tetrafluoroboric acid adduct (24 mg), potassium fluoride (80 mg) and tris(dibenzylideneacetone) dipalladium (0) (27 mg) in tetrahydrofuran (8 ml) was stirred at room temperature for 2 days under argon atmosphere. Added thereto was a saturated aqueous ammonium chloride solution and the mixture was extracted with ethyl acetate. The extract was dried over magnesium sulfate. The solvent was evaporated under reduced pressure and the residue was purified by silica gel column chromatography (hexane:ethyl acetate=90:10-70:30) to give 1-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-3-(5-(6-fluoro-3-pyridyl)-2-thienylmethyl)-4-methylbenzene 59 (44 mg) as colorless crystals. APCI-Mass m/Z 631 (M+NH4). (3) The above 1-(2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl)-3-(5-(6-fluoro-3-pyridyl)-2-thienylmethyl)-4-methylbenzene 59 (39 mg) was dissolved in 1,4-dioxane (4 ml)-tetrahydrofuran (4 ml), and added thereto was 2N sodium hydroxide (2 ml). The mixture was stirred at room temperature for one hour. The mixture was made acidic by addition of an aqueous citric acid solution, and the mixture was extracted with ethyl acetate. The extract was washed successively with a saturated aqueous sodium hydrogen carbonate solution and brine, and then dried over sodium sulfate. The solvent was evaporated under reduced pressure to give the desired 1-(β-D-glucopyranosyl)-3-(5-(6-fluoro-3-pyridyl)-2-thienylmethyl)-4-methylbenzene 60 (34 mg) as colorless powder. APCI-Mass m/Z 463 (M+NH4).

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