Chloroacetyl chloride → 1-(2-Chloro-6-fluorophenyl)-5-methylindolin-2-one

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Reaction Steps

Alternatively, a mixture of 169.8 g of crude N-(2′-chloro-6′-fluorophenyl)-4-methylaniline, 172 ml (2.15 mol) of chloroacetyl chloride in 580 ml of toluene is heated under a nitrogen atmosphere for 2 hours at 70°. The reaction is cooled to room temperature, 450 ml of decane is added, and the volatiles are distilled off under 200 mbar pressure at 62-72°. To the mixture is added 150 ml of toluene and 385 g of aluminum chloride (2.87 mol) slowly at 20-40°. The mixture is heated at 120° for 5 hours, cooled to 20°, and added over 30 minutes to 800 ml of ethyl acetate. The mixture is quenched by addition to a pre-cooled solution of 67 ml of 37% hydrochloric acid in 800 ml of water at 20±100, and the resultant mixture is filtered through a pad of Celite. The organic layer is separated and the volatiles are distilled off. To the residue is added 100 ml of heptane and the mixture is cooled to 0° over a 30 minute period and stirred for one hour. The mixture is filtered and the filter cake is washed three times with 45 ml of heptane. To the crude product is added 90 g of charcoal (DARCO G-60) and 4500 ml of methanol. The mixture is heated to reflux for two hours, cooled to room temperature, and filtered through a pad of Celite. After distilling off 4390 ml of methanol, the mixture is cooled to 15°. The product is collected by filtration, washed three times with 30 ml of methanol, and dried to give N-(2′-chloro-6′-fluorophenyl)-5-methyloxindole.

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