Abstract
A series of novel amphiphilic monoazacrown ethers (1 a-n) have easily been prepared in high yields by addition reaction of monoaza-15-crown-5 and -18-crown-6 to homologous 1, 2-epoxyalkanes and alkyl glycidyl ethers in methanol.
They were examined for cloud point and critical micelle concentration in aqueous solution, complexing stability constants with alkali metal cations in methanol and phase-transfer catalysis on Finkelstein reaction.
The hydrophilicity and cation-complexing ability of N-alkylmonoazacrown ethers was progressively enhanced by introducing a β-hydroxyl group and the additional insertion of ether oxygen into the alkyl side chain. In spite of their great hydrophilicity, the crown ethers (1) with 18-membered ring had high phase-transfer catalytic efficiency which was superior to that of dicyclohexano-18-crown-6 (3) and similar to that of N-dodecylmonoaza-18-crown-6 (2 b), indicating that the excellent catalysis of (1) to be due to cation-complexation ability.
