1. Add 800 mL of anhydrous ethanol to a dry triple-necked flask, initiate stirring and cool the reaction system to 0-5 °C.
2. 430 mL of acetyl chloride was slowly added dropwise, and the rate of dropwise acceleration was controlled to maintain the reaction temperature at 0-5 °C. 3.
3. after the dropwise addition, keep the reaction system at 0-5°C for a period of time.
4. 85 g of 6-cyano-2-naphthol was added to the reaction system, warmed to 10 °C and kept for 10 hours.
5. After completion of the reaction, methyl tert-butyl ether was added, stirred for 1 hour and filtered.
6. The filter cake was washed with methyl tert-butyl ether, dried and mixed with ethanol.
7. The mixture was heated to 50°C and bubbled with dry ammonia for 3 hours. 8.
8. At the end of the reaction, the solvent was removed by evaporation under reduced pressure to give a yellow solid.
9. The solid was stirred with saturated sodium bicarbonate solution for a period of time, filtered and washed with water to neutral. 10.
10. Suspend the product in methanol and add appropriate amount of methanesulfonic acid solution dropwise. 11.
11. Add methyl tert-butyl ether to precipitate the solid, filter and wash with methyl tert-butyl ether.
12. Recrystallization was carried out with ethanol to give 75 g of a yellow solid product with a melting point of 227-230 °C and a yield of 53%.
