Synthesis
GENERAL STEPS: To a mixed solution of methanol (5 mL) and tetrahydrofuran (5 mL) of 2-methoxycarbonyl-5-phenylthiophene (437 mg) was added 1 N aqueous sodium hydroxide (3 mL), and the reaction was stirred for 2 hours at room temperature. After completion of the reaction, 1 N hydrochloric acid (5 mL) was slowly added to the reaction mixture for acidification. The precipitated solid was collected by filtration and washed with a small amount of cold water and dried under vacuum to give 5-phenylthiophene-2-carboxylic acid (397 mg, 97.1% yield). The product was confirmed by NMR hydrogen spectrum (DMSO-d6, δ): 7.3-7.5 (3H, m), 7.58 (1H, d, J = 3.9 Hz), 7.6-7.8 (3H, m), 13.15 (1H, wide s). Electrospray mass spectrometry (ESI-MS) showed m/z: 203 ([M-H]-).
References
[1] Patent: US6770667, 2004, B1. Location in patent: Page column 11
[2] ChemMedChem, 2011, vol. 6, # 2, p. 362 - 377
[3] European Journal of Medicinal Chemistry, 2017, vol. 137, p. 96 - 107
[4] Journal of Medicinal Chemistry, 2010, vol. 53, # 15, p. 5536 - 5548
