反应详情

120 g of 2,3-dihydroxynaphthalene, 132 g of ZN(CN)2 (zinc cyanide) and 1.32 g of potassium chloride in 1200 ml of absolute ether were placed in a 2.5 l sulfonation flask equipped with inlet-tube, stirrer, thermometer, reflux condenser and calcium chloride tube. Hydrogen chloride gas was introduced for 6 hours while cooling with ice and stirring. Subsequently, the ether was decanted and destroyed with sodium hydroxide. In order to remove the residual ether, the oily residue was evacuated hot, then treated with 800 ml of water and stirred at 60° C. on a steam-bath. The cooled mixture was filtered under suction and the material on the suction filter was dried at 40 ° C. in vacuo. The crude product was dissolved in acetonitrile while warming, filtered and, after concentration in vacuo, crystallized. There were obtained 121.3 g (85.7% of theory) of 2,3-dihydroxy-naphthaldehyde of melting point 132°-133° C.

1. customequipped with inlet-tube, stirrer
2. temperaturethermometer, reflux condenser and calcium chloride tube
3. temperaturewhile cooling with ice
4. customSubsequently, the ether was decanted
5. customdestroyed with sodium hydroxide
6. customIn order to remove the residual ether
7. customthe oily residue was evacuated hot
8. additiontreated with 800 ml of water
9. stirringstirred at 60° C. on a steam-bath
10. filtrationThe cooled mixture was filtered under suction
11. filtrationthe material on the suction filter
12. customwas dried at 40 ° C. in vacuo
13. dissolutionThe crude product was dissolved in acetonitrile
14. temperaturewhile warming
15. filtrationfiltered
16. concentrationafter concentration in vacuo
17. customcrystallized