Potassium Carbonate → 1-(4-trifluoromethylphenyl)imidazolidin-2-one

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Reaction Steps

To a solution of methyl 4-trifluoromethylaniline (3.47 g, 21.6 mmol) in dry toluene (50 mL) was added 2-chloroethylisocyante (2.50 g, 2.02 mL, 23.7 mmol). The mixture was stirred at 40° C. for 12 h. After cooling to room temperature, the solid was collected by filtration and washed with toluene, water and dried in air to provide 1-(2-chloro-ethyl)-3-(4-trifluoromethylphenyl)urea [5.28 g, 92.0%, >95% pure by LC/MS MS (ES+) m/z: 267, 269]. The urea (5.27 g, 23.7 mmol) was then stirred in DMF (50.0 mL) with K2CO3 (3.27 g, 11.98 mmol) at room temperature for 12 h. The solid was filtered off and the solvent was removed in vacuum. The crude product was dissolved in dichloromethane and passed through a silica column (50 g) and eluted with dichloromethane:ethyl acetate, 8:2 to give pure cyclic urea intermediate, 1-(4-trifluoromethylphenyl)imidazolidin-2-one, as white crystalline material (3.85 g, 84.7%). MS (ES+) m/z: 231.

Provenance & Evidence