Nikolaus Guttenberger

Graz University of Technology | TU Graz · Institute of Organic Chemistry

Arsenolipids include a wide range of organic arsenic species that occur naturally in seafood and thereby contribute to human arsenic exposure. Recently arsenic-containing phosphatidylcholines (AsPCs) were identified in caviar, fish, and algae. In this first toxicological assessment of AsPCs, we investigated the stability of both the oxo- and thioxo...

Arsenolipids, especially arsenic-containing hydrocarbons (AsHC), are an emerging class of seafood originating contaminants. Here we toxicologically characterize a recently identified oxo-AsHC 332 metabolite, thioxo-AsHC 348 in cultured human liver (HepG2) cells. Compared to results of previous studies of the parent compound oxo-AsHC 332, thioxo-AsH...

Although fish and seafood are well known for their nutritional benefits, they contain contaminants that might affect human health. Organic lipid-soluble arsenic species, so called arsenolipids, belong to the emerging contaminants in these food items; their toxicity has yet to be systematically studied. Here, we apply the in vivo model Caenorhabditi...

In this contribution, we report synthetic strategies towards potential ligands for the study of binding differences between PhzE, the first enzyme in the biosynthesis of phenazines, and the related enzyme anthranilate synthase. The ligands were designed with the overriding goal to develop new antibiotics via downregulation of phenazine biosynthesis...

This review covers formal insertion reactions of diazo compounds into aldehydes for the formation of ketones (Csingle bondH bond insertion) and homologated aldehydes (Csingle bondC bond insertion). The Roskamp homologation and related reactions have become powerful tools for the construction of Csingle bondC bonds in organic synthesis. Recently, ef...

Lipid-soluble arsenic compounds, also called arsenolipids, are ubiquitous marine natural products of currently unknown origin and function. In our search for clues about the possible biological roles of these compounds, we investigated arsenic metabolism in the unicellular green alga Dunaliella tertiolecta, and discovered an arsenolipid fundamental...

Lipid-soluble arsenic compounds, also called arsenolipids, are ubiquitous marine natural products of currently unknown origin and function. In our search for clues about the possible biological roles of these compounds, we investigated arsenic metabolism in the unicellular green alga Dunaliella tertiolecta, and discovered an arsenolipid fundamental...

We wish to disclose the first synthesis of 1-O-hexadecanoyl-2-O-((15-(dimethylarsinoyl)pentadecanoyl)oxy)-sn-glycero-3-phosphocholine, which belongs to the group of arsenic-containing phosphatidylcholines (AsPCs), recently discovered in herring caviar. The synthesized product will serve as model compound to study biological and toxicological proper...

The previously unknown arsenic-containing triacylglycerides (AsTAGs) 3-((15-(dimethylarsinoyl)pentadecanoyl)oxy)propane-1,2-diyl dipalmitate 1 and 2-((15-(dimethylarsinoyl)pentadecanoyl)oxy)propane-1,3-diyl dipalmitate 2 have been synthesized. They will serve as model compounds in the search for naturally occurring AsTAGs, recently proposed natural...

The previously unknown arsenic-containing triacylglycerides (AsTAGs) 3-((15-(dimethylarsinoyl)pentadecanoyl)oxy)propane-1,2-diyl dipalmitate 1 and 2-((15-(dimethylarsinoyl)pentadecanoyl)oxy)propane-1,3-diyl dipalmitate 2 have been synthesized. They will serve as model compounds in the search for naturally occurring AsTAGs, recently proposed natural...

Phenazines are natural products which are produced by bacteria or by archaeal Methanosarcina species. The tricyclic ring system enables redox processes, which producing organisms use for oxidation of NADH or for the generation of reactive oxygen species (ROS), giving them advantages over other microorganisms. In this review we summarize the progres...

Two previously unknown arsenic-containing cyclic ethers have been synthesized, namely (((2R,3R,4S,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)methyl)dimethylarsine oxide and its C-1 epimer (((2S,3R,4S,5R)-3,4-dihydroxy-5-(hydroxymethyl)tetrahydrofuran-2-yl)methyl)dimethylarsine oxide as its trifluoroacetate salt. The compounds serve as...

A library of star-shaped 2H-imidazolines has been synthesized via Debus Radziszewski-condensation from 1,2-diketones and ketone starting materials. Selective reduction of one imine group of the 2H-imidazole intermediate with LiAlH4 or catalytic flow hydrogenation furnished 2H-imidazolines, which could be conveniently diversified by reacting the ami...

The synthesis of the 5-unsubstituted pyrido[3,2,1-jk]carbazol-6-one 4 can be achieved by the reaction of carbazole (1) and malonate derivatives, either in a three-step synthesis via 5-acetyl-pyridocarbazolone 3 or in a one-step reaction from 1 and malonic acid/phosphoryl chloride. The 5-acetyl derivative 5 can be transformed via a tosylate intermed...