Benzocrown Derivatives as Ionophores for Alkali Cations, I. - Synthesis of Urethane- and Urea-Linked Mono- and Bis-Crown Ethers
New mono- and bis-benzocrown ethers (5-28 and 29-48) with different substituents and connecting chains were prepared with the aim to develop novel alkali cation-transport mediators for biological systems.The alkali cation selectivities of the title compounds were determined in ion-selective membrane electrodes.Remarkable potassium selectivity was observed with several bis(benzo-15-crown-5)urethanes.