Synthesis
The general procedure for the synthesis of methyl 2-fluoro-4-bromophenylacetate from methanol and 2-fluoro-4-bromophenylacetic acid was as follows: a mixture of 2-fluoro-4-bromophenylacetic acid (20.2 g, 86.6 mmol) and concentrated sulfuric acid (7 mL) in methanol (200 mL) was heated and refluxed for 18 hours. After completion of the reaction, the solvent was removed by distillation under reduced pressure. The residue was dissolved in dichloromethane (200 mL), washed sequentially with saturated sodium bicarbonate solution and brine, and the organic phase was dried with anhydrous sodium sulfate. After filtration, the organic phase was concentrated under reduced pressure to give methyl 2-fluoro-4-bromophenylacetate (21.1 g, 99% yield) as a brown oil. Mass spectrum (ESI): m/z = 280.1 [M + H]+.
References
[1] Patent: WO2017/108723, 2017, A2. Location in patent: Page/Page column 225; 226
[2] Patent: US2014/194383, 2014, A1. Location in patent: Paragraph 0386-0388; 0390
[3] Patent: WO2014/141187, 2014, A1. Location in patent: Page/Page column 54; 55
[4] Patent: WO2016/38519, 2016, A1. Location in patent: Page/Page column 36; 37
[5] Patent: WO2016/38552, 2016, A1. Location in patent: Page/Page column 51
