Synthesis
General procedure for the synthesis of methyl 5-bromofuran-2-carboxylate from methanol and 5-bromo-2-furoic acid: 5-bromo-2-furoic acid (950 mg, 5.00 mmol) was accurately weighed and dissolved in 10 mL of methanol, and 2 mL of sulfoxide chloride (SOCl2) was added slowly and dropwise. Upon completion of the reaction, the reaction mixture was cooled to room temperature and the solvent was subsequently removed by evaporation under reduced pressure. The residue was dissolved in an appropriate amount of toluene and this dissolution and evaporation process was repeated three times to give the intermediate 5-bromo-2-furoic acid methyl ester in 100% yield.
References
[1] Patent: CN103992311, 2017, B. Location in patent: Paragraph 0103; 0104; 0105; 0106; 0123; 0124; 0125
[2] Organic Letters, 2012, vol. 14, # 22, p. 5644 - 5647
[3] Patent: CN106977476, 2017, A. Location in patent: Paragraph 0103-0105
[4] Patent: WO2015/159103, 2015, A1. Location in patent: Page/Page column 33; 34; 37
[5] Patent: WO2015/1024, 2015, A1. Location in patent: Page/Page column 65
