213546-89-5 21H,23H-Porphine-7,17-dione, 8,18-dihydro-8,18-dihydroxy-2,8,13,18-tetramethyl- 8,18-Dihydroxy-2,8,13,18-tetramethyl-8,18-dihydro-21H,23H-porphine-7,17-dione