Synthesis of Hydroxyisooxophlorins by Oxidative Degradation of meso-Hydroxyporphyrins.

Hydroxyisooxophlorin is an oxidatively degraded porphyrin that contains one carbonyl carbon, one hydroxymethylene group, and two sp2-methine groups at its meso positions. Here we report that oxidation of a free-base meso-hydroxyporphyrin with [bis(trifluoroacetoxy)iodo]benzene in the presence of H2O afforded two regioisomers of hydroxyisooxophlorins, 10-hydroxy-10-iso-5-oxophlorin and 15-hydroxy-15-iso-5-oxophlorin, as major and minor products, respectively. We also examined the reaction mechanism, acid-mediated isomerization, metal complexation behavior, and physical properties of these molecules.