Thiacalix[4]arenes with Triple Bonds at the Lower Rim: Synthesis and Structure

Abstract

Reaction of thiacalixarenes with propargyl bromide in the presence of potassium or cesium carbonates leads mainly to mixture of the corresponding tetrasubstituted derivatives adopting 1,3-alternate and partial cone conformations. Sodium salts like carbonate and hydride are not effective as the base for the etherification of lower rim of thiacalix[4]arenes by propargyl bromide. It was established that propargyl derivatives of thiacalix[4]arenes are in conformational exchange between forms due rotation of one aryl ring.