1. 5-Fluoro-2-iodobenzoic acid was dissolved in an appropriate amount of solvent, 13.87 mol/L thionyl chloride was added, heated to 60°C and the reaction was stirred overnight until complete clarification. The progress of the reaction was monitored by TLC (unfolding agent: petroleum ether/ethyl acetate=10/1). Upon completion of the reaction, the solvent was removed by evaporation, toluene was added and evaporated to dryness, and the resulting product was dissolved in ethyl acetate and set aside.
2. 3658 g of diethyl malonate was dissolved in 55 L of ethyl acetate, and 4762 g of magnesium chloride was slowly added at room temperature for 30 minutes. Subsequently 4877 g of triethylamine was added dropwise and stirring was continued for 30 minutes. The reaction mixture was cooled to 5°C in an ice bath, the organic phase was washed with saturated saline (10 L x 2) and stirred for 2 h at room temperature. The completion of the reaction was confirmed by TLC (unfolding agent: petroleum ether/ethyl acetate = 10/1).
3. The organic layer was separated and the solvent was evaporated to give a red oil. To the oily substance was added 12 L of a mixture consisting of acetic acid, water and concentrated sulfuric acid in the ratio of 6.6:4.4:1 by volume, heated to 100°C, and the reaction was stirred overnight. After completion of the reaction, the organic phase was washed with saturated saline (10 L x 2).
4. The organic phase was further washed with 0.5 N sodium hydroxide solution (30 L × 1) and saturated saline (10 L × 2). Finally, it was purified by silica gel column chromatography (unfolding agent: petroleum ether/ethyl acetate = 8/1) to give 3.6 kg of the target product 1-(5-fluoro-2-iodophenyl)ethanone.
