Selective O-functionalization of phenolic α-amino acids with crown ethers bearing cyclophosphazene sub-units

Cyclophosphazenes (CyP) containing a crown ether and an α-amino acid unit have been prepared starting from diphosphaza[16]crown-6 (PNP16C6). Nucleophilic substitution of one (or both) residual ansa-chlorine atom(s) of bis-spiro substituted PNP16C6 by α-arylsulfonamido esters containing a phenolic function leads to the target compounds. These new polyfunctionalized CyP are lariat ethers, potentially useful as starting materials for the preparation of ‘pH-controlled active ion carriers’ in liquid membranes.