4-Bromo-2-fluoroaniline → 2-(4-Bromo-2-fluorophenylamino)-1-methyl-6-oxo-1,6-dihydropyridine-3-carboxylic acid

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Reaction Conditions

Reaction Steps

Preparation of 2-(4-bromo-2-fluorophenylamino)-1-methyl-6-oxo-1,6-dihydropyridine-3-carboxylic acid methyl ester: To a solution of 4-bromo-2-fluorophenylamine (0.192 g, 1.01 mmol) in THF (5 mL) at −78° C. under N2 was added lithium bis(trimethylsilyl)amide (1.50 mL, 1.50 mmol, 1 M solution in hexanes) dropwise. The reaction mixture was stirred for one hour at −78° C. 2-Chloro-1-methyl-6-oxo-1,6-dihydropyridine-3-carboxylic acid methyl ester (0.202 g, 1.00 mmol) was then added dropwise as a solution in THF (5 mL) and the reaction mixture was stirred for one hour at −78° C. The reaction mixture was quenched by the addition of H2O and the pH was adjusted to pH 7 with saturated NH4Cl and then diluted with EtOAc. The organic layer was separated and washed with saturated NaCl, dried (Na2SO4), and concentrated under reduced pressure. Purification by flash column chromatography (methylene chloride/EtOAc, 15:1) gave 0.232 g (65%) pure desired product as a white crystalline solid.

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