Thorsten Mordhorst

Penilumamide, a novel lumazine peptide isolated from the marine-derived fungus, Penicillium sp. CNL-338

A novel lumazine peptide, penilumamide (1), was isolated from the fermentation broth of a marine-derived fungal strain, identified as Penicillium sp. (strain CNL-338) and the structure of the new metabolite was determined by analysis of ESI-TOF MS data combined with 1D and 2D NMR experiments.

Synthesis of 3-Alkyl Pyridinium Alkaloids from the Arctic Sponge Haliclona viscosa

3-Alkyl pyridinium alkaloids (3-APAs) are common secondary metabolites in marine sponges of the order Haplosclerida. In recent years, our laboratory has isolated and synthesized several new members of this family such as haliclamines C–F, viscosamine, viscosaline and a cyclic monomer. All of them were isolated from the Arctic sponge Haliclona viscosa collected in Spitsbergen, Norway. In this article we report the syntheses of these secondary metabolites from Haliclona viscosa and related compounds and give a short overview of the bioactivity.

Investigation of a betainic alkaloid from Punica granatum

Spectroscopic investigations reveal that a hydroquinone pyridinium alkaloid isolated from the leaves of pomegranates Punica granatum L. (X-ray) exists as a mixture of a conjugated and a cross-conjugated heterocyclic mesomeric betaine in aqueous and DMSO-d6 solution. Twofold deprotonation yields an anionic tripole.

From uncharged to decacationic molecules: syntheses and spectroscopic properties of heteroarenium-substituted pyridines.

Nucleophilic substitutions on pentachloropyridine with 4-(dimethylamino)pyridine, 4-aminopyridine, and 4-(pyrrolidin-1-yl)pyridine give mono-, tri- and pentacationic pyridine-hetarenium salts. The mono-, tri- and pentacationic 4-aminopyridine derivatives can be deprotonated to neutral compounds in solution, or protonated to di-, hexa- and decacationic pyridine derivatives, respectively. Successive substitutions with different heteroaromatic nucleophiles give pyridines with two distinct types of heteroarenium substituents.

Studies on photocatalytically active materials containing structure elements of a pyridinium alkaloid from Punica granatum

The alkaloid punicin from Punica granatum, N-(2′,5′-dihydroxyphenyl)pyridinium chloride, forms heterocyclic mesomeric betaines and radicals, which were examined by ESR measurements and DFT calculations, in aqueous solution. By reaction of poly(4-vinylpyridine) with p-benzoquinone under two different reaction conditions, polymeric structures with punicin constituents were prepared and characterized. The ESR signals of these polymers were calculated and discussed. The 4,4′-bipyridine derivative of these polymers was prepared starting from Merrifield resin which was subsequently reacted with 4,4′-bipyridine and p-benzoquinone, or, alternatively, with N-(2″-5″-dihydroxyphenyl)-4-(4′-pyridine)pyridinium chloride. The properties of these new materials in reversible photocatalytic processes via radical species were examined. Therefore, solutions or suspensions were irradiated in water in the presence of proflavinium as a sensitizer, and EDTA as a sacrificial donor under an inert atomsphere. Oxygen (air) recovers the starting materials by formation of hydroxide ions which were determined by pH measurements.

Structure Elucidation of Submilligram Quantities of Natural Products - Application to Haliclamines G and H from the Arctic Marine Sponge Haliclona viscosa

Two new haliclamines were identified directly from the crude extract of the Arctic sponge Haliclona viscosa using improved chromatographic conditions and a detailed knowledge about the fragmentation pattern of haliclamines. These are haliclamine G (1) with two alkyl chains of equal length (10 methylene groups) and haliclamine H (2) with alkyl chains of 10 and 12 methylene groups. Due to the limited amount of sponge material available, the haliclamines were not isolated, and the structure elucidation relied on the chromatographic and mass spectrometric comparison with synthetic compounds Graphical Abstract Structure Elucidation of Submilligram Quantities of Natural Products - Application to Haliclamines G and H from the Arctic Marine Sponge Haliclona viscosa

Syntheses and Properties of Di- and Tricationic Hetarenium-Substituted Pyrimidines

2,4-Dichloro-, 4,6-dichloro-, 2,4,6-trichloro- and tetrachloropyrimidine undergo nucleophilic displacements by 4-(dimethylamino)pyridine to give (pyrimidine-2,4-diyl)-1,1’-bis[4-(dimethylamino) pyridinium] dichloride, (pyrimidine-4,6-diyl)-1,1’-bis[4-(dimethylamino)-pyridinium] dichloride, (pyrimidine-2,4,6-triyl)-1,1’,1”-tris[4-(dimethylamino)pyridinium] trichloride, and (5- chloropyrimidine-2,4,6-triyl)-1,1’,1”-tris[4-(dimethylamino)pyridinium] trichloride, respectively. Nucleophilic substitutions of the pyridinium substituents by O- and S-nucleophiles to functionalized pyrimidines are examined

Synthesis of 4-(dimethylamino)pyridinium-substituted pyrazine, pyridazine, 1,3,5-triazine, purine, and imidazole

Substitution reactions of 2,3-dichloropyrazine, 3,6-dichloropyridazine, 2,4,6-trichloro-1,3,5-triazine, 2,6-dichloropurine, and N-tosyl-2,4,5-tribromo-imidazole with 4-(dimethylamino)pyridine to monocationic, dicationic, and tricationic hetarenium salts are described.

Synthesis of Pyridine-Thioethers via Mono- and Tricationic Pyridinium Salts

On nucleophilic substitution with S-nucleophiles at room temperature, 1-(4-dimethylamino)- [2,3,5,6-tetrachloropyridin-4-yl]pyridinium chloride (2) yielded tetrachloro-4-sulfanylpyridines and 2,3,5-trichloro-4,6-disulfanylpyridines depending on the reaction conditions. Similarly, the tricationic (3,5-dichloropyridine-2,4,6-triyl)-1,1’,1”-tris[4-(dimethylamino)pyridinium] trichloride 3 was reacted with S-nucleophiles to give the corresponding 3,5-trichloro-2,4,6-trisulfanylpyridines under mild conditions.