Sodium Thiosulfate → 5-Nitro-2-thenoic acid

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Reaction Steps

5-Nitro-2-thiophenecarbaldehyde (7.86 g) was dissolved in acetonitrile (50 ml), and sodium dihydrogen phosphate (1.6 g) in water (20 ml) and 30% aqueous hydrogen peroxide (5.9 ml) were added. Furtherl sodium chlorite (8.0 g) in water (70 ml) was added dropwise under ice-cooling. The reaction mixture was stirred at room temperature for 2 hours, and then sodium thiosulfate was added to remove an excess amount of hydrogen peroxide. The mixture was alkalified with 1N sodium hydroxide and extracted with diethyl ether. The aqueous layer was acidified with 1N hydrochloric acid and extracted with ethyl acetate. The extract was dried over anhydrous magnesium sulfate and concentrated under reduced pressure to give 5-nitro-2-thiophenecarboxylic acid (7.83 g) as crystals.

Provenance & Evidence