4-Trifluoromethyl-2-hydroxyquinoline has a wide range of applications in the pharmaceutical field and can be used as an intermediate for antibacterial, antiviral, anti-inflammatory and antitumor drugs.
4-Trifluoromethylquinolin-2(1H)-one was prepared by reacting aniline and ethyl-4,4,4-trifluoroacetoacetate stirred in toluene.
Experimental Procedure: In a 1 L round flask fitted with a reflux condenser a mixture of 25.60 g aniline, 50.0 g ethyl-4,4,4-trifluoroacetoacetate 300 ml toluene was heated to reflux in an oil bath at 130 °C. After 20 min 3 ml water was added and the mixture was heated at reflux for another 24 h. the reaction mixture was cooled to room temperature and concentrated under reduced pressure. A round flask with 200 mL H2SO4 was heated to 80°C and the crude oil from the step before was added in portions to the H2SO4 keeping the internal temperature below 90°C, total addition time was approximately 40 min. After addition was complete, the mixture was stirred at 80°C for 1 h, cooled and poured onto 400 g crushed ice. The resulting solids were filtered, washed with water, and dried under vacuum at 40°C to give 33.0 g (50%) product (2-Hydroxy-4-(trifluoromethyl)quinoline) as a colorless solid.
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