BIOSYNTHESIS AND SYNTHESIS OF BIOACTIVE NATURAL LACTAMS

A lactam group is a characteristic structural element of many microbia l secondary metabolites. Examples of own biosynthetic studies are the cytochalasans and pseurotins which are gamma-lactams. Detailed results are presented for the beta-lactam tabtoxin (wildfire toxin) and tabto xinine beta-lactam. The biosynthetic building blocks were established. The methyl group of L-methionine provides the carbonyl-C-atom of the beta-lactam moiety. In the course of approaches to the synthesis, 1-am inocyclopropanecarboxylic acid, 1-aminocyclopropanol (coprinol) and co prine, which are both inhibitors of aldehyde dehydrogenase, were synth esized. In view of the formation of the beta-lactam ring a new alpha-b enzyloxyacryl Iron(II) complex for the synthesis of alpha-hydroxy-alph a,alpha-dialkylcarbonyl derivatives was prepared. Finally, studies on the biosynthesis of the spirostaphylotrichins, a family of spirocyclic gamma-lactams, are presented. Having established the building blocks a series of minor metabolites of the wild type and of mutant strains w ere isolated and their structures elucidated.