22913-26-4

Colorless to yellow liquid

A catalytic amount of concentrated sulfuric acid (0.5 mL) was added to a solution of 3-thiophenecarboxylic acid (2.0 g, 15.60 mmol) in methanol (30 mL), and the reaction mixture was heated to reflux for 2 hours. After completion of the reaction, the solvent was removed by distillation under reduced pressure. The residue was poured into ice-cold water and extracted with ethyl acetate (3 × 20 mL). The organic layers were combined, washed with saturated brine and dried over anhydrous sodium sulfate. After filtration, the organic phase was concentrated under reduced pressure to give methyl 3-thiophenecarboxylate (1.8 g, 81% yield) as a colorless oil.

[1] Patent: WO2006/123145, 2006, A1. Location in patent: Page/Page column 44
[2] Recueil des Travaux Chimiques des Pays-Bas, 1934, vol. 53, p. 643,648
[3] Recueil des Travaux Chimiques des Pays-Bas, 1936, vol. 55, p. 991
[4] Patent: WO2016/115013, 2016, A1. Location in patent: Page/Page column 70
[5] Patent: WO2006/108701, 2006, A1. Location in patent: Page/Page column 61