Synthesis of lipophilic crown ethers with pendant carboxylic acid groups
ABSTRACT Synthetic routes to thirteen highly lipophilic crown ether carboxylic acids are described. Seven contain 12–15-membered crown ether units with four ring oxygens and are designed for lithium ion complexation. Three others possess large ring 24-crown-8, 27-crown-9, and 30-crown-10 units. Six new hydroxymethyl crown ethers are prepared as synthetic intermediates.