Substituted calix[n]arenes. Synthesis ofp-isopropylcalix[4]arene and the structure of its benzene clathrate

p-Isopropylcalix[4]arens was synthesized by alkylation of unsubstituted calix[4]arene in the presence of ferric chloride hexahydrate. The structure of the compound and its benzene clathrate was established by NMR spectroscopy and X-ray diffraction analysis.