A New Approach Towards Synthesis of Some Novel “Upper Rim” Functionalized Calix[4]resorcinarene Schiff-bases

Chemistry Department, School of Sciences, Gujarat University, Ahmedabad-380009, Gujarat, India.
* Corresponding author: E-mail: mitesh9@gmail.com
Tel.: +91-79-26300969, Fax: +91-79-26308545,

Abstract
Synthesis of new “upper rim” functionalized calix[4]resorcinarene Schiff-bases has been carried out by reacting tetraaminocalix[4]resorcinarene with different aromatic aldehydes in ethanol at reflux temperature. The tetra-aminocalix[4]resorcinarene, which can serve as very good precursor for various derivatizations at the extra annular position, was synthesized for the first time through tetra-azo intermediate, by first introducing the azo functionality at the upper rim, and subsequent reduction with Na₂S₂O₄ in aq. NaOH. Synthesized Schiff-bases were characterized by elemental analysis, FT-IR, NMR and Mass spectral data. Their complexation ability with Cu(II) is also investigated.

Keywords: Calix[4]resorcinarene; upper rim; Na₂S₂O₄; Schiff-base