The chemical structure of pemptoporphyrin.

1. Pemptoporphyrin dimethyl ester was further purified on an alumina column and then crystallized from chloroform and methanol with melting point 215-218 degrees . The absorption spectra in the visible and ultraviolet with molar extinction coefficients are presented. 2. The nuclear-magnetic-resonance spectrum of pemptoporphyrin dimethyl ester in deuterochloroform solution is reported, together with those of several other porphyrins. 3. One vinyl and one hydryl group were found at positions 2 and 4 (or 4 and 2) in the molecule. The structure of pemptoporphyrin is 2(4)-hydryl-1,3,5,8-tetramethyl-4(2)-vinyldeuteroporphyrin IX. 4. Reduction of pemptoporphyrin dimethyl ester with resorcinol gave deuteroporphyrin IX dimethyl ester.