Synthesis of a new class of difunctional tetraphenylene crown ethers

Article abstract of DOI:10.1139/v98-188

Three new substituted tetraphenylene crown ethers have been made. Bis(5- carbomethoxy-1,3-phenylene)-bis(p-phenylene)-(3x + 6)-crown-x, where x = 12, 16, and 20 (11b-11d) were synthesized via [1 + 1] cyclization of methyl 3,5- bis[ω-chloro(oligoethyleneoxy)]benzoates (13b-3d) with methyl 3,5-bis[ω- (p-hydroxyphenoxy)(oligoethyleneoxy)]benzoates (16b-6d) using K₂CO₃ as base and tetrabutylammonium iodide as a phase transfer agent in dimethylformamide (DMF). The corresponding 30-membered (x = 8) macrocycle 11a could not be made by this approach; only the elimination product, 3,5-bis(vinyloxy)benzoic acid (19), was isolated. 16a-16d were made via alkylation of p-benzyloxyphenol (14) with 13a-13d, respectively, followed by hydrogenolysis with Pd/C as catalyst. No complexation of these macrocycles with dibenzylammonium ions was detected by NMR spectroscopy, but weak complexation of 11d with a paraquat derivative was observed.