A new bile acid-derived lariat-ether: design, synthesis and cation binding properties

A new chola lariat ether (1, a 21-crown-6) was constructed fromreadily available precursors. The association constant of compound 1 with alkali metal picrates was measured using Cram's extraction protocol. Evidence is presented for the involvement of the 3-methoxy group for the complexation. Energy minimised structures show that the A-ring gets slightly distorted upon metal ion binding