Synthesis
To a 60 mL dry egg-shaped flask was added 6-bromo-2-naphthalenecarboxylic acid (2.4996 g, 10.0 mmol) followed by 20 mL of anhydrous methanol to dissolve it. Slowly 1 mL of concentrated sulfuric acid was added dropwise to the reaction system and then the mixture was refluxed overnight. The progress of the reaction was monitored by TLC until complete conversion of the feedstock. After completion of the reaction, the heating was stopped and the system was allowed to cool to room temperature. The reaction was quenched with saturated aqueous sodium carbonate and the reaction system was adjusted to neutral. The reaction mixture was extracted with ethyl acetate and the organic phase was washed with saturated aqueous sodium carbonate, water and saturated aqueous sodium chloride, respectively. The organic layer was dried over anhydrous sodium sulfate and concentrated under reduced pressure to give methyl 6-bromo-2-naphthalenecarboxylate (S7, 2.63 g, 100% yield) as a white solid.
References
[1] Tetrahedron, 2009, vol. 65, # 7, p. 1349 - 1360
[2] Journal of the American Chemical Society, 2008, vol. 130, # 50, p. 16836 - 16837
[3] Patent: CN107286150, 2017, A. Location in patent: Paragraph 0153; 0154; 0155; 0156; 0157
[4] European Journal of Medicinal Chemistry, 2015, vol. 102, p. 277 - 287
[5] Patent: JP2016/37458, 2016, A. Location in patent: Paragraph 0172; 0173
