38939-88-7

39608-47-4

The general procedure for the synthesis of 3-chloro-4-nitrobenzoic acid from 3-chloro-4-nitrotoluene was as follows: 3-chloro-4-nitrotoluene (1.2 g, 6.99 mmol) was dissolved in a solvent mixture of water and pyridine (2:1, 30 mL), and heated at 90 °C. Subsequently, potassium permanganate (5.2 g, 32.9 mmol) was added in 4 batches at 1.5 h intervals. After the reaction mixture was continuously heated at 90 °C for 8 h, potassium permanganate (2 g) was added additionally and the mixture was stirred at the same temperature overnight. Potassium permanganate (2 g) was added again and stirring was continued at 90 °C for 1 hour. After completion of the reaction, the solids were removed by filtration through a CELITE pad. Water (50 mL) was added to the filtrate and the mixture was acidified to pH < 2 and subsequently extracted three times with ethyl acetate. The organic phases were combined, washed sequentially with water and saturated saline, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to afford 1.19 g (84% yield) of 3-chloro-4-nitrobenzoic acid as a light yellow solid, which did not need to be further purified.