BIOSYNTHESIS OF PORPHYRINS AND RELATED MACROCYCLES - PART 49 - EXPLORATION OF SYNTHETIC ROUTES TO ANALOGS OF THE SPIRO-INTERMEDIATE FOR PORPHYRIN BIOSYNTHESIS

The proposed intermediacy of the spiro-pyrrolenine 1 for the biosynthe sis of uroporphyrinogen III has focussed attention on its synthesis. S everal different approaches to close analogues of this compound are ex plored, including (a) the synthesis of a dilactone bridged dipyrrolic pyrrolenine, (b) deactivation of two of the pyrrole rings of the macro cycle by attaching 3-methoxycarbonyl groups and (c) approaches to spir o-macrocyclic compounds via dipyrroketones. The chemistry of the diffe rent types of synthetic intermediates is described.