60 °C and filtered, and the solvent was evaporated in vacuo, to give the crude product, which was purified by chromatography on alumina with EtOAc as eluent to give 2-[(benzyloxy)methyl]-2-methyl-15-crown-5 as a colorless oil: 79%; IR (film) 1249, 1114 (CO) cm'1;

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The bis‐crown ethers (IV)‐(VI) are prepared from the dihydroxy compound (II), and a study of their complexation properties towards alkali and ammonium ions is carried out.

The bis(crown ethers) (III) mentioned in the title are prepared by coupling the oligomeric ethylene glycol derivatives (II) or (IV) with the tetrahydroxybiphenyl (I).