Synthesis of selectively formylated calixarene ethers

By careful choice of a catalyst (TiCl4 or SnCl4), temperature, reaction time and mole ratio of the substrate to dichloromethylmethylether, it has been possible to obtain new functionalized formylated calix[n]arenes in the cone or partial cone conformation. Optimized general reaction procedures for obtaining mono-, di-, tri- and tetraformylated derivatives of calix[4]arenes as exemplified by formylation of tetramethoxy-, tetrakis(2-ethoxyethoxy)-, bis(ethoxycarbonylmethoxy)- and bis(hexadecyloxy)-calix[4]-arenes have been reported.