Acetic Anhydride → 7-(2-Thienyl)-3-(2,3-di-O-acetyl-beta-D-ribofuranosyl)-3H-imidazo[4,5-b]pyridine

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Reaction Steps

Compound 12 (120 mg, 0.19 mmol) was azeotroped three times with anhydrous pyridine. This was dissolved in anhydrous pyridine (1.9 ml), and 72 μl (0.76 mmol) of acetic anhydride was further added thereto. This mixture was stirred at room temperature for 7 hours and poured into 5% NaHCO3 (50 ml) and ethyl acetate (50 ml). The organic layer was washed once with saturated aqueous sodium chloride, dried over Na2SO4, and then evaporated under reduced pressure to remove the solvent. The residue was azeotroped twice with toluene and dissolved in CH2Cl2 (19 ml), followed by addition of 190 μl dichloroacetic acid at 0° C. This reaction mixture was stirred at 0° C. for 15 minutes. The mixture was poured into 5% NaHCO3 and extracted with CH2Cl2. The organic layer was washed once with saturated aqueous sodium chloride, dried over Na2SO4, and then evaporated under reduced pressure to remove the solvent. The product was purified by flash silica gel chromatography using a 2% methanol-methylene chloride solution as a solvent to give 77 mg of Compound 13 in a yield of 93%.

Provenance & Evidence