PREPARATION OF BACTERIOPETROPORPHYRINS BY PARTIAL SYNTHESIS FROM THE CHLOROBIUM CHLOROPHYLLS

Chemical degradation of the natural bacteriochlorophyll d homologous mixture to give the corresponding bacteriopetroporphyrin methyl esters is described. Reduction of the corresponding methyl bacteriopheophorbide d homologue with excess of sodium borohydride, followed by oxidation with 2, 3-dichloro-5, 6-dicyanobenzoquinone, affords the corresponding bacteriopetroporphyrin. NMR spectroscopy of the nickel(II) complexes is used to establish that the pigments are identical with those isolated from immature Messel oil shale. Similar degradative transformations of the bacteriochlorophyll c homologues (and also of the bacteriochlorophyll e mixture) to give “bacteriopetroporphyrins c” (which have not yet been observed in oil shales) are reported, and the proton NMR signatures of their nickel(II) complexes are obtained and assigned. © 1990, American Chemical Society. All rights reserved.