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Research discusses intramolecular bridging in the preparation of calix[8]arene-based calix[8]mono-crowns using polyether chains as bridging elements. The methodology involves direct alkylation of p-tert-butylcalix[8]-arene to obtain four calix[8]mono-crown regioisomers in good yields. Data indicate that introduction of a single polyether chain does not affect the mobility of calix[8]arene macrocycle.

The alkylation of p-tert-butylcalix(8)arene with p-methylbenzyl bromide in the presence of a weak base, cesium fluoride, results mainly to the production of mono(p-methylbenzyl)calix(8)arene; 1,3-bis(p-methylbenzyl) calix(8)arene; 1,3,5,7-tetrakis(p-methylbenzyl)calix(8)arene; 1,2,3,5,7- pentakis(p-methylbenzyl)calix(8)arene and heptakis(p-methylbenzyl)calix(8)- arene. A series of different monoalkylation steps lead to the various partially benzylated calix(8)arene.

Para-tert-butylcalix(8)arene reacts with various alkylating agents in the presence of weak bases to produce partially O-substituted derivatives. 1,3,5, 7-tetraethers have C4 symmetry in the main product due to alternating steps of monodeprotonation and alkylation. Monodeprotonation leads to hydrogen bonds-stabilized phenoxide monoanions. Stability of monoanions and electrophile dimension influence the reaction pathway.

The kinetic analysis of the reaction sequence for the free acids determines that the observed rate constant, k1, proportional to [ArOH](sub 0)(super -1/2) along with the experimental behavior of phenols. The results interpret that the impurities influence the ionization equilibrium of phenols and either reduces or enhances the measured rate constants.