From Large Furan-Based Calixarenes to Calixpyrroles and Calix[n]furan[m]pyrroles: Syntheses and Structures

Abstract

The cyclic hexamer obtained by the condensation of furan and acetone can be used as a convenient starting material for the syntheses of calix[6]pyrrole 1 and of several “hybrid systems” containing both furan and pyrrole units. The solid-state structure of 1 shows a water molecule held inside the cavity by six hydrogen-bonding interactions, while that of the “alternating” calix[3]furan[3]pyrrole 2 contains no water molecules, despite the macrocycles having a similar structure.