Uses
2-Amino-4,5-dimethyl-3-thiophenecarboxylic Acid Ethyl Ester is used in the preparation triazine and pyrimidine derivatives as anti-inflammatory and analgesic agents. Also used in the synthesis of antioxidants through heteroaryl amines as well as CB2 cannabinoid receptor partial agonists.
Synthesis
To a 100-mL round-bottomed flask were added 2-butanone (20 g, 0.28 mol, 1.0 eq.), ethyl cyanoacetate (31.4 g, 0.28 mol, 1.0 eq.), and sulfur powder (8.9 g, 0.28 mol, 1.0 eq.), followed by ethanol as a solvent. Diethylamine (21 g, 0.28 mol, 1.0 eq.) was added dropwise to the above mixture. The reaction system was stirred continuously for 8 hours at room temperature. After completion of the reaction, the reaction mixture was diluted with water and the resulting precipitate was collected by filtration. Purification by ethanol recrystallization afforded ethyl 2-amino-4,5-dimethylthiophene-3-carboxylate as a yellow solid (41 g, 75% yield).
References
[1] Synthetic Communications, 2012, vol. 42, # 16, p. 2367 - 2374
[2] Bulletin of the Korean Chemical Society, 2011, vol. 32, # 6, p. 2091 - 2092
[3] Organic and Biomolecular Chemistry, 2014, vol. 12, # 24, p. 4233 - 4242
[4] Journal of Sulfur Chemistry, 2014, vol. 35, # 3, p. 261 - 269
[5] Journal of Heterocyclic Chemistry, 2014, vol. 51, # SUPPL. 1, p. E216-E221
