Upper Rim Diester-bridged Calixarenes and Oligocalix-arenes: the Effects of the Length of Bridged Reagents on Their Distribution

A series of monobridged calixarenes 3a-f, cyclic biscalix arenes 4a-f, diametrically bridged at the upper rim with saturated aliphatic diester chains, have been synthesized. The results at dilute conditions show that the percentage of yields of mono , bis and oligo calixarenes are related to the length of the chains. With the shortening of the chains, the percentage of monocalixarenes decreased. All the calixarene moieties are in a cone conformation according to the AB quartet pattern of the methylene protons between the phenolic rings in the 1H NMR spectra.