BIOSYNTHESIS OF PORPHYRINS AND RELATED MACROCYCLES. PART 27. SYNTHESES OF MODIFIED HYDROXYMETHYLBILANES AND STUDIES OF THEIR CHEMICAL AND BIOLOGICAL PROPERTIES.

Article abstract of DOI:10.1016/S0040-4020(01)87379-8

The biosynthetic pathway to uroporphyrinogen-III, the parent macrocycle for all the pigments of life, involves the formation and ring-closure of an hydroxymethylbilane.The non-enzymic ring-closure of this bilane is studied under different pH conditions.Also octamethyl esters of related bilanes are synthesised which have either a cyano or a methyl group blocking position-19 which is free on the terminal ring-D of the natural bilane.Studies are made of the ring-closure of these substituted bilanes under acidic conditions.The conclusion is reached that there is a strong preference for non-enzymic ring-closure of an hydroxymethylbilane to occur at the terminal carbon atom (position-19).The octa-acids derived from the cyano and methyl substituted bilanes inhibit the action of cosynthetase on the natural hydroxymethylbilane.