Synthesis of Calix[3]dipyrrins by a Modified Lindsey Protocol

摘要

The Lindsey protocol, a one-pot two-step reaction between pyrrole and an aldehyde, has been extensively used for the synthesis of porphyrins and has been revealed in recent years to provide various other pyrrolic macrocycles, such as corroles, sapphyrins, N-confused porphyrins, and meso-aryl-substituted expanded porphyrins, depending upon the concentrations, additives, reaction medium, stoichiometry of the pyrrole and aryl aldehyde, and structures of the substrates. The Lindsey protocol usually requires anhydrous conditions because of the dehydrative nature of the first condensation reaction between pyrrole and the aldehyde and may be influenced by the presence of water.