Extensive methodology screening of meso-tetrakys-(furan-2-yl)-porphyrin microwave-assisted synthesis

Two novel microwave-assisted synthetic procedures for the preparation of meso-tetrakys-(furan-2-yl)-porphyrin are herein reported. A solvent-free method which uses solid supported reagents has been deeply investigated. However, yields were further improved when working in dioxane under heterogeneous catalysis. The reaction rate, yields and impurity profiles have been optimized as a function of all the main parameters: temperature, microwave power, concentration, time and metal ions. The Zn(II) porphyrin complex was obtained in acceptable yields after only 10 min of irradiation. Also included are preliminary studies on Diels-Alder reactions with furanyl derivatives which aim to achieve further porphyrin derivatization.