含嘧啶环的双冠醚(Ⅱ)

Bis-Crown Ether Containing Pyrimidine Ring (Ⅱ )

由4,6-二氯-5-硝基嘧啶、2,4-二氯-5-硝基-6-甲基嘧啶分别与4＇-氨基苯并冠醚反应合成了6种以嘧啶环为桥链的新双冠醚,其中分别含有苯并-12-冠-4(A1,B1)、苯并-15-冠-5(A2,B2)和苯并-18-冠-6(A3,B3)单元,用这些双冠醚的氯仿溶液对碱金属苦味酸盐水溶液进行了萃取,计算了萃取平衡常数K-e。结果表明双冠醚(A1,B1)、(A2,B2)和(A3,B3)分别对钠、钾和铯具有较高的萃取能力,其选择性显著优于相应的单冠醚。

Six bis-crown ethers containing benzo-12-crown-4(A1,B1) , benzo-15-crown-5(A2,B2) and benzo-18-crown-6(A3,B3) moieties bridged by pyrimidine ring were prepared by the reaction of 4,6-dichloro-5-nitropyrimidine, 2, 4-dichloro-5-nitro-6-methylpyrimidine with the 4'-aminoben-zocrown ethers, respectively. Extractions were carried out from aqueous solution of alkali metal pi-crates with these bis-crown ether solutions in chloroform. The extraction equilibrium constants were also evaluated . The results indicate that compound (A1,B1), (A2,B2) and (A3,B3) are effective extracting reagents for sodium, potassium and caesium, respectively. The cation-selectivity is more effective than the corresponding monocyclic crown ethers.