2-Trifluoromethylimidazole-4-carboxylic acid was prepared by decarboxylation of 2-trifluoromethylimidazole-4,5-dicarboxylic acid through heating. The specific reaction procedure is as follows: 2-Trifluoromethylimidazole-4,5-dicarboxylic acid (0.75 g) was heated at 250 °C for 15 minutes; carbon dioxide was evolved. The brown residue (0.54 g) was boiled with charcoal suspended in methanol and filtered. The filtrate was evaporated to leave a residue, a portion (0.17 g) of which was sublimed at 130 °C (30 mmHg); a fraction was collected and, after washing with hot trichloromethane, yielded 2-trifluoromethylimidazole-4-carboxylic acid (0.10 g), m.p. 264–5 °C (decomposes)[1].
