Tetra-crowned porphyrin as P450 biomimetic model for carbamazepine oxidation

Abstract

A substituted porphyrin bearing four crown ether units, H 2 (TCP), was synthesized from the reaction between (5,10,15,20-tetra(o-aminophenyl)porphyrin) and the acyl derivative of the ether (4-carboxy-18-crown-6). The free-base porphyrin was characterized by C, N, and H elemental analysis; UV-vis and IR spectroscopies; and 1 H NMR. The corresponding ironporphyrin, Fe(TCP)Cl, was obtained via iron insertion into H 2 (TCP). Fe(TCP)Cl was employed as catalyst for carbamazepine (CBZ) oxidation by iodosylbenzene (PhIO), 3-chloroperoxybenzoic acid (m-CPBA) or sodium hypochlorite (NaOCl), in methanol or in a biphasic water/dichloroethane system. The crowned ironporphyrin proved to be a highly efficient and selective catalyst for CBZ epoxidation even in the biphasic dichloroethane /H 2 O system, with no need for an additional phase transfer agent.