Microwave‐Assisted Synthesis of p[n]arene Catalyzed by KOH

Abstract

The paper researched the synthesis of p-methylcalix[6]arene and ptertbutylcalix[8]arene catalyzed by KOH in moderate yields under microwave irradiation. The effects of different factors on this condensation reaction have been discussed. Compared with classical method, this method had some merits such as easy obtaining the raw materials, short reaction route, simple and convenient aftertreatment, being beneficial to environmental protection.

Green Synthesis of Oligomer Calixarenes

“…To yield a larger cyclic reaction product, the amounts of bases used were increased with a longer reflux time. As previously discussed, bases and reflux time play a role in cyclic formation [45].…”

“…Organic synthesis using microwave technology has been largely employed, as it can accelerate the reaction time as a consequence of an increase in heating that cannot be achieved with conventional heating [44]. This is what happened in Baozhi's [45] synthesis of p-methylcalix [6] arene. A reaction compound consisting of formaldehyde, p-methylphenol, and KOH was heated with microwave for 2-8 min (output power at 100%).…”

Conventional vs. Microwave- or Mechanically-Assisted Synthesis of Dihomooxacalix[4]arene Phthalimides: NMR, X-ray and Photophysical Analysis

“…The syntheses of p-alkylcalix [n]arenes (R = t-Bu, n = 4 and 8; R = Me, n = 6) were the first calixarene reactions carried out under MW irradiation [15,16]. Other examples reported are the preparation of water-soluble azocalix [4]arenes [17], the copper(I)-catalysed syntheses of calix [4]arene glycoconjugates [18] and calix [4]arene tetraazide derivatives [19], as well as calix [4]arenes containing chiral unsymmetrical urea moieties at the lower rim [20].…”