Synthesis of lipophilic crown ethers with pendant carboxylic acid groups

Abstract

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.