Azacrown Ethers from Mustard Carbonate Analogues

Polycondensation of a nitrogen mustard carbonate analogue with aromatic diols under dilution conditions affords a series of azacrown ethers previously not easily accessible as they require multistep synthesis including protection, purification, cyclization and methylation. This novel synthesis relies upon the anchimeric effect of the nitrogen mustard carbonate and it does not require the use of any base. Crowning glory: Several diazacrown ethers incorporating nitrogen mustard moieties have been prepared by treating harmless mustard carbonates with aromatic diols in the absence of any base under pseudo-high dilution conditions (see scheme). This novel synthesis relied upon the anchimeric effect of the nitrogen mustard carbonate.