Synthesis
General procedure for the synthesis of methyl 2-bromomethyl-4-cyanobenzoate from methyl 4-cyano-2-methylbenzoate: Methyl 4-cyano-2-methylbenzoate (4.0 g, 22.83 mmol) was dissolved in carbon tetrachloride (150 mL) and N-bromosuccinimide (NBS, 4.88 g, 27.4 mmol) was added to form a suspension. The suspension was heated at 80 °C for 5 min. Subsequently, azobisisobutyronitrile (AIBN, 1.88 g, 11.42 mmol) was added and stirred continuously at 80 °C for 16 hours. After completion of the reaction, the mixture was cooled to room temperature and filtered. The filtrate was concentrated to give the crude product. Purification by silica gel column chromatography using a solvent mixture of ethyl acetate (EA) and petroleum ether (gradient elution, 0% to 5% EA) resulted in methyl 2-bromomethyl-4-cyanobenzoate (3.84 g, 66.9% yield) as a white solid.
References
[1] Patent: WO2017/201069, 2017, A1. Location in patent: Paragraph 0510
[2] Patent: US5591752, 1997, A
[3] Patent: US2009/82368, 2009, A1. Location in patent: Page/Page column 41-42
[4] Patent: WO2013/79452, 2013, A1. Location in patent: Page/Page column 165
[5] Patent: US2014/45855, 2014, A1. Location in patent: Paragraph 0552
