Synthesis of fully aromatic cyclic polyethers
Abstract
Ullmann-type condensation of 2,2′-oxydiphenol (2) with o-bromoanisole followed by treatment of the products with hydroiodic acid gave 2,2′-(o-phenylenedioxy)diphenol (4) and 2,2′-[oxydi-(o-phenylene)dioxy]diphenol (6). Similarly, compound (6) gave the homologous pentameric (8) and hexameric (10) diphenols. On condensation with o-dibromobenzene, the diphenol (8) gave hexabenzo-18-crown-6 (13), and the diphenol (10) gave heptabenzo-21-crown-7 (14). Condensation of the trimer monomethyl ether with o-dibromobenzene gave the open-chain heptamer (12). Unlike their aliphatic or partly aliphatic analogues the fully aromatic cyclic polyethers (13) and (14) did not bind cations of alkali metals.