Biosynthesis of porphyrins and related macrocycles. Part 50.1 Synthesis of the N-formyl-dihydro analogue of the spiro-intermediate and its interaction with uroporphyrinogen III synthase

Abstract

The proposed intermediacy of the spiro-system 1 for the biosynthesis of uroporphyrinogen III has focused attention on its synthesis. In this paper the approach that is explored is to carry a dihydropyrrole through the entire synthesis with the intention of converting it into a 2H-pyrrole (pyrrolenine) in one of the final steps. The chemistry of the different types of synthetic intermediates is described and also it is demonstrated that the N-formyl dihydropyrrole 37 is a strong inhibitor of cosynthetase. The conclusion is reached that of all the possible routes to the spiro-pyrrolenine 1, that via the protected dihydropyrrole 30 shows the greatest promise.