Synthesis and crystal structure of 15α,20α-di(4-hydroxylphenyl)calix[4]pyrroles and 10α,20β-di(4-hydroxylphenyl)calix[4]pyrroles

In the presence of methanesulfonic acid as catalyst, the condensation reactions of 5,5′-dialkyldipyrromethanes with p-hydroxyacetophenone in methanol resulted in a mixture of the unexpected polysubstituted 15α,20α-di(4-hydroxylphenyl)calix[4]pyrroles and the expected 10α,20β-di(4-hydroxylphenyl)calix[4]pyrroles in comparable lower yields. The crystal structures of the new calix[4]pyrroles and their oxyacetate derivatives were successfully determined by X-ray diffraction and the intermolecular interactions in the solid state is briefly discussed.