SYNTHESIS OF CALIX[6]ARENES PARTIALLY FUNCTIONALIZED AT THE UPPER RIM

Several new examples of calix[6]arenes selectively functionalized at t he upper rim are reported. Starting from calix[6]arenes 1,3,5-tri-, 1, 2,4,5-tetra- and 1,2,3,4,5-pentaalkylated at the lower rim, it is poss ible to isolate macrocycles 2,4,6-tri-, 3,6-di- and 6-mono functionali zed at the upper rim (18-94% yield) with nitro, formyl, bromo, chlorom ethyl and 2-propenyl groups. Modifications of these moieties allow the synthesis of macrocycles bearing amino, amido, hydroxymethyl, carboxy , cyano and chloromethyl functions which can be used for further trans formation and preparation of new molecular receptors, based on calix[6 ]arenes, which have different geometries. Examples of di- and triquino nes on the hexameric macrocycle are also reported.