Syntheses of oxygen analogues of sulfhemes-A and -C

Article abstract of DOI:10.1016/0040-4020(95)00953-1

Syntheses of metal-free oxygen analogues of the sulfhemes-A and -C from protoporphyrin-IX dimethyl ester I are presented. Oxasulfporphyrin-C dimethyl ester 5 is obtained by intramolecular displacement of a primary tosylate by a tertiary hydroxyl in an appropriately constructed precursor 18, or by surface-catalyzed rearrangement of the epoxide-bearing oxasulfporphyrin-A dimethyl ester 23. Compound 23 is in turn prepared by Mitsunobu type internal dehydration of the precursor 12. The methodology is then successfully extended to more symmetric porphyrin systems. Compounds 23, 25, 46, and 61/62 are the first porphyrin epoxides to be synthesized.