Dimethylformamide → 4-Chloro-2-{[2-(2-chloro-3,6-difluoro-phenyl)-acetyl]-methyl-amino}-6-methyl-nicotinic acid ethyl ester

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Reaction Steps

Oxalyl chloride (0.19 ml) was added dropwise to a solution of (2-chloro-3,6-difluoro-phenyl)-acetic acid (373 mg) in dichloromethane (5 ml) at ambient temperature. A drop of N,N-dimethylformamide (“DMF”) was added to initiate the reaction. The reaction mixture was stirred at ambient temperature for 1 hour. The reaction mixture was concentrated to give a colourless oil which was dissolved in dichloromethane (5 ml). The mixture was added dropwise to a slurry of 4-chloro-6-methyl-2-methylamino-nicotinic acid ethyl ester (Example 4.1) (413 mg) and pyridine (0.16 ml) in dichloromethane (5 ml). The reaction mixture was stirred at ambient temperature for 16 hours. The reaction mixture was partitioned between dichloromethane and water. The phases were separated and the organic layer was concentrated. The residue was purified by column chromatography on silica gel (eluent: ethyl acetate/hexane 1:4) to give 4-chloro-2-{[2-(2-chloro-3,6-difluoro-phenyl)-acetyl]-methyl-amino}-6-methyl-nicotinic acid ethyl ester as a yellow solid (299 mg). 1H NMR (400 MHz, CDCl3): 7.32 (bs, 1H), 7.00-7.05 (m, 1H), 6.90-6.96 (m, 1H), 4.43-4.45 (m, 2H), 3.66 (s, 2H), 3.24 (m, 3H), 2.60 (s, 3H), 1.37-1.40 (t, 3H) ppm.

Provenance & Evidence