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 9 (247 mg, 0.4 mmol) was azeotroped with pyridine, followed by addition of pyridine (4 ml) and acetic anhydride (75 μl, 0.8 mmol). After stirring at room temperature for 12 hours, the reaction mixture was partitioned between ethyl acetate and 5% aqueous NaHCO3, and the organic layer was washed with 5% aqueous NaHCO3. This organic layer was dried over anhydrous sodium sulfate, concentrated and azeotroped with toluene. The residue was then dissolved in methylene chloride (40 ml). To this reaction mixture, dichloroacetic acid (400 μl) was added at 0° C. and stirred for 15 minutes at 0° C. The reaction mixture was partitioned with 5% aqueous NaHCO3, and the organic layer was washed with 5% aqueous NaHCO3. After drying over anhydrous sodium sulfate, the organic layer was concentrated and purified on a silica gel column to give Compound 13 (125 mg, 87%).

Provenance & Evidence