Synthesis
(DHQ)2PHAL was prepared by etherification of 1,4-dichlorophthalazine and hydrogenated quinine under alkaline conditions. The preparation reaction formula is shown in the figure below: 
Reaction formula for the preparation of hydroquinine 1,4-(2,3-diazanaphthalene) diether
Add 50 mL of sulfolane to a 250 mL flask, add 1,4-dichlorophthalazine and hydroquinine with stirring, then add potassium carbonate, stir and heat to 150 ℃ for reaction. After 9 h of reaction, take a sample for analysis. The reaction endpoint is defined as the content of hydroquinine being less than 0.5% (GC normalized content). If the reaction endpoint is not reached, continue the reaction at the specified temperature until the endpoint is reached. After the reaction was complete, the temperature was lowered to below 100 °C, 100 mL of hot water was added, and the temperature was raised to 95 °C and stirred for 2 h. After stirring, the mixture was allowed to stand and separate into layers. The upper aqueous layer was removed, and the lower organic layer was washed twice with 200 mL of water, each time with 100 mL of water (the washing method was: heat to 95 °C, stir for 2 h, let stand and separate into layers, and remove the upper aqueous layer). The three upper aqueous solutions were combined and awaited the next step of recovering sulfolane. After washing, 150 mL of water was added to the organic layer, the temperature was raised to 95 °C, and the mixture was stirred for 2 h. The mixture was allowed to stand and separate into layers, and the upper aqueous layer was removed. Finally, 100 mL of water was added to the organic layer, the temperature was raised to 95 °C, and the mixture was stirred and then cooled to crystallize. The mixture was cooled to about 35 °C and filtered. The filter cake was washed with water and dried to obtain hydrogenated quinine.;
