Macroheterocycles. Part 44. Facile synthesis of azacrown ethers and cryptands in a two-phase system

Abstract

A facile procedure is proposed for the preparation of azacrown ethers and cryptands by condensation of dibromides or ethylene glycol bis(toluene-p-sulphonate)s with acyclic bis(sulphonamide)s or with bis[2-(p-tolylsulphonylamino)ethyl]diazacrown ethers, respectively. The reaction was carried out in a two-phase system of aqueous alkali-toluene (benzene) in the presence of quaternary ammonium salts as phase transfer catalysts. The catalytic activity decreased in the sequence: Bu₄NI ≈ Bu₄NBr > Bu₄NCl > Bu₄NHSO₄ > Et₃NCH₂C₆H₅NCl. Maximum yields of twelve-membered azacrown ethers are obtained when lithium hydroxide is used, while crown ethers of larger size are observed in the presence of sodium or potassium hydroxides; this may be due to a template effect.