Cone and 1,3-alternate conformers of 1,3-bis(ethoxycarbonylmethoxy)-2,4-dihydroxycalix[4]arene and 1,2,3,4-tetrakis(ethoxycarbonylmethoxy)calix[4]arene.

The two title ethoxycarbonylmethoxy derivatives of calix[4]arene, namely diethyl 2,4-dihydroxycalix[4]arene-1,3-diyldi(oxyacetate), C(36)H(36)O(8), (I), and tetraethyl calix[4]arene-1,2,3,4-tetrayltetra(oxyacetate), C(44)H(48)O(12), (II), form two different conformations, viz. a cone in (I), where intramolecular hydrogen bonds are formed through OH groups in a partially substituted calix[4]arene, and a 1,3-alternate form of a completely substituted calix[4]arene in (II). A unique three-dimensional array of molecules exists in (II), with the channels extended along the entire crystal.