16188-55-9

1878-66-6

5188-07-8

16188-55-9

1. 10 g of 4-bromophenylacetic acid was dissolved in 20 mL of DMF under nitrogen protection. 2. 5.0 g of sodium methanethiol and 0.5 g of copper powder were added for nitrogen displacement. 3. The reaction mixture was heated to 130 °C under nitrogen protection and the reaction was stirred for 24 hours. 4. After the reaction was completed, it was cooled to room temperature. 5. The reaction mixture was processed according to the method of Example 1 to finally obtain 4-methylthiophenylacetic acid in 79.3% yield. Alternative steps: 1. 10 g of 4-bromophenylacetic acid was dissolved in 20 mL of DMF under nitrogen protection. 2. 5.0 g of sodium methanethiol and 0.1 g of cuprous bromide were added for nitrogen substitution. 3. The reaction mixture was heated to 130 °C under nitrogen protection and the reaction was stirred for 4 hours. 4. Upon completion of the reaction, the mixture was cooled to room temperature, 5mL of 40% NaOH solution was added and stirred for 10 minutes. 5. Extracted twice with 25mL of ethyl acetate and combined the organic phases. 6. Add 50mL of ethyl acetate and adjust pH to 2-4 with 10% dilute sulfuric acid. 7. Collect the ethyl acetate layer and wash with 10mL of water. 8. Concentrate ethyl acetate to about 20mL by distillation, add 20mL hexane. 9. Heat to reflux to completely dissolve the solid, slowly cool to room temperature and filter to obtain yellow crystals. 10. 6.38g of 4-methylthiophenylacetic acid was obtained after drying in 76.1% yield.