Synthesis of rctt, rccc, and rcct diastereomers of calix[4]methylresorcinarenes based on p-tolualdehyde. X-ray diffraction study of the rcct isomer. Formation of rctt and rccc cavitands in a cone conformation

Abstract

Synthesis of rctt, rccc, and rcct diastereomers of calix[4]methylresorcinarenes based on p tolualdehyde. X ray diffraction study of the rcct isomer. Formation of rctt and rccc cavitands in a cone conformationThe reaction of 2 methylresorcinol with p tolualdehyde afforded rctt and rccc diastereo mers of calix[4]methylresorcinarene and an insignificant amount of the rcct isomer. The structure of the latter was established by X ray diffraction analysis. The macrocycle in the rcct isomer adopts a 1,2 diplanar conformation, in which one pair of adjacent resorcinol fragments is nearly orthogonal to another pair of resorcinol fragments. The supramolecular organization of the diastereomer in the crystal was studied. The tolyl fragments form the outer surface of the layers composed of the macrocycles, which are separated by "interlayers" of solvent molecules. Cavitands adopting a cone conformation were prepared from the rctt and rccc diastereomers by linking the adjacent phenoxy groups through methylene bridges. The structure of the rctt cavitand was confirmed by 2D NMR spectroscopy.