Monopyrrolic Natural Compounds Including Tetramic Acid Derivatives

Silver‐Catalyzed Hydroamination: Synthesis of N‐Bridgehead Pyrroles, Incorporating a Protection‐Deprotection Strategy for Preparation of Cyclic Secondary Vinylogous Carbamates

“…Pyrroles are amongst the most recognisable structures in organic chemistry; this being due to the enormous amount of research focussed on their synthesis and reactivity, [1] as well as their abundance in nature either as monopyrrolic compounds [2] or cyclic tetrapyrroles (porphyrins, chlorins etc.). [3] We have recently reported a novel one-pot synthesis of pyrroles via the silver-mediated reaction of secondary vinylogous amides or carbamates with propargyl bromide.…”

Metal complexes of natural melophlins and their cytotoxic and antibiotic activities

“…3-Acyltetramic acids frequently possess distinct antibiotic or antineoplastic properties [1][2][3]. This has been rationalized by their ability to chelate biochemically indispensable metal ions and to mimick phosphate groups in the binding site of kinases and phosphatases.…”

“…Synthetic complexes with other metals were also reported, e.g. Cu(TA) 2 , Ni(TA) 2 and Fe(TA) 3 [5][6][7]. As part of a study of the melophlins, a group of pharmaco logically promising 3-acyl-N-methyltetramic acids isolated from the marine sponge Melophlus sarasinorum [8][9][10], we investigated some of their complexes with metal fragments of known intrinsic bioactivity.…”

Domino syntheses of bioactive tetronic and tetramic acids

“…Tetramic acids also show a remarkable diversity in terms of biogenetic descent as well as structural variations and types of biological activity (Ghisalberti 2003;Gossauer 2003;Royles 1995). Their high polarity and the fact that they can exist in various tautomeric forms, with the 2,4-diketo form shown in Fig.…”

“…For example, eukaryotic plasmodial slime molds as well as higher fungi frequently contain yellow pigments that protect them from microbial attack, e. g., physarorubinic acid in Physarum polycephalum (Nowak and Steffan 1997). Meanwhile, a host of other "composite" tetramic acids were isolated and characterized which have fatty acid residues, sugar rings or isoprenoid moieties, or combinations of these attached at various positions of the pyrrolidine-2,4-dione core (Ghisalberti 2003;Gossauer 2003;Royles 1995 tetramic and tetronic acids is slowly shifting toward marine habitats. With the mariculture of invertebrates having made considerable progress, even the mass production of promising marine drug candidates appears viable now (Brümmer and Nickel 2003).…”