117724-63-7

117724-62-6

117724-63-7

General procedure for the synthesis of 2-methyl-4-(trifluoromethyl)thiazole-5-carboxylic acid from ethyl 2-methyl-4-trifluoromethyl-5-thiazolecarboxylate: 115 g of ethyl 2-methyl-4-(trifluoromethyl)thiazole-5-carboxylate (0.102 mol) was dissolved in ethyl acetate at room temperature, and 50 g of 40% sodium hydroxide solution was added dropwise slowly into a reaction vessel with controlled The acceleration of the drop was controlled to maintain the temperature of the reaction system below 40 °C. After the dropwise addition, the reaction temperature was maintained and stirring was continued for 60 minutes. After the reaction was completed, the organic phase was separated and 10% hydrochloric acid solution was slowly added to the organic phase to adjust the pH value of the system to ≤2, at which time a large amount of solid precipitate precipitated. The precipitate was filtered and the filter cake was washed twice with 10% hydrochloric acid solution and subsequently dried in a vacuum oven. The resulting 2-methyl-4-(trifluoromethyl)thiazole-5-carboxylic acid was a light yellow solid with a yield of 21.5 g, a purity of 98.8% and a reaction yield of 98.70%.