Synthesis, spectra and crystal structures of calix[4]arenes with ethoxycarboxymethoxy group onlower ring - way to water soluble calix[4]arenes
Abstract
Symmetrically tetrasubstituted calix[4]arene derivatives cone-5,11,17,23-tetranitro-25,26,27,28-tetrakis(ethoxycarbonylmethoxy)calix[4]arene 1, cone-5,11,17,23-tetraamino-25,26,27,28-tetrakis(ethoxycarbonylmethoxy)calix[4]arene 2, cone-5,11,17,23-tetrakis(2-pyridylmethimino)-25,26,27,28-tetrakis(ethoxycarbonylmethoxy)-calix[4]arene 3a, cone-5,11,17,23-tetrakis(3-pyridylmethimino)-25,26,27,28-tetrakis-(ethoxycarbonylmethoxy)calix[4]arene 3b, cone-5,11,17,23-tetrakis(4-pyridylmethi-mino)-25,26,27,28-tetrakis(ethoxycarbonylmethoxy)calix[4]arene 3c and cone-5,11,-17,23-tetrakis(2-pyrrolylmethimino)-25,26,27,28-tetrakis(ethoxycarbonylmethoxy)calix-[4]arene were synthesized and characterized. Crystal structures of compounds 1 and 3b are also reported.
These upper rim nitro- and imino-substituted compounds are precursors for water soluble symmetrically tetrasubstituted calix[4]arene derivatives.