Nitric Acid → 4-Nitrothiophene-2-carboxylic acid

Participants

Reaction Steps

2-Thiophenecarboxylic acid (6.4 g, 50 mM) was suspended in acetic anhydride (15 ml) and fuming nitric acid (16 ml) in glacial acetic acid (25 ml) added slowly over 1 hour with stirring, while keeping the temperature of the reaction mixture below 30° C. The reaction mixture was stirred at ambient temperature for 2 hours. The product was purified by subjecting to chromatography (470 ml) on HP20SS resin using methanol/(water+1% acetic acid): 0/100→50/50 as eluant. The pure title compound was obtained (1.3 g) together with a mixture of 4- and 5- nitrothiophene-2-carboxylic acid (4.4 g).

Provenance & Evidence