Synthesis
GENERAL STEPS: 2-Fluoro-4-iodonicotinic acid (5.13 g) was dissolved in a solvent mixture of ether (25 mL) and methanol (25 mL) under nitrogen protection. To this solution was slowly added a 10% hexane solution of trimethylsilylated diazomethane (32.9 g). The reaction mixture was stirred at room temperature for 3 hours. Upon completion of the reaction, the reaction solution was concentrated and the resulting residue was purified by silica gel column chromatography (eluent: hexane-ethyl acetate gradient) to afford methyl 2-fluoro-4-iodonicotinate (5.3 g). The structure of the product was confirmed by 1H NMR (300 MHz, DMSO-d6): δ 3.94 (3H, s), 7.98 (1H, dd, J = 5.3, 1.1 Hz), 8.07 (1H, dd, J = 5.3, 0.8 Hz).
References
[1] Patent: EP2921480, 2015, A1. Location in patent: Paragraph 0391; 0392
[2] Patent: WO2016/95204, 2016, A1. Location in patent: Page/Page column 62; 63
