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Phytochemical studies of the wood and the stem bark of Tridesmostemon omphalocarpoides Engl. (Sapotaceae) led to the isolation of omphalocarpoidone (1), a new lanostane-type furano-spiro-γ-lactone together with β-amyrin acetate (2), taraxerol (3), spinasterol (4), lichexanthone (5), epi-catechin (6), spinasterol 3-O-β- d -glucopyranoside (7), tormentic acid (8), and 1,2,3,4-tetrahydronorharman-1-one (9). Their structures were established on the basis of extensive NMR studies, mass spectrometry, and by comparison of the data with those previously reported in the literature. The structure of the new secondary metabolite was later confirmed by X-ray crystallography. Except for spinasterol, the antimicrobial activities of these secondary metabolites were investigated on ten bacterial strains and the alkaloid 9 showed a significant activity against Escherichia coli with a MIC at 16 μg/mL.

Three secondary fungal metabolites 1–3 with a benzo[b]naphtho[2,1-d]furan skeleton were isolated from submerged cultures of the ascomycete Allantophomopsis lycopodina. The NMR-based structure elucidation was challenging due to a low H/C ratio of only 0.64 and 0.68, respectively. NMR measurements in two different solvents and the use of NMR experiments such as HSQC-TOCSY and LR-HSQMBC proved to be helpful in this respect. The proposed structures obtained from the comprehensive analysis of the NMR data were verified by comparison of recorded and computed NMR chemical shifts from quantum chemical calculations of several constitutional isomers and were further analyzed with the aid of the DP4 and DP4+ probabilities.

Three new cyclopropanic oleanane triterpenoids and ten known compounds were obtained from Donella ubanguiensis using chromatographic methods. The structures were established on the basis of mass spectrometric and NMR data and by comparison with values reported in the literature. The structures of the new compounds were confirmed by X-ray crystallography. A part of the isolated compounds was evaluated for cytotoxic and antimicrobial activities.

From three basidiomycetes, Xeromphalina sp., Stereum sp., and Pleurocybella porrigens, six triquinane sesquiterpenes with unprecendented modifications and a rearranged sesquiterpene related to coriolin C have been isolated. Their isolation, structure elucidation, and biological evaluation are described.

Bioactivity-guided fractionation of extracts from the fungus IBWF79B-90A resulted in the isolation of three known naphthoquinones, herbarin, dehydroherbarin, and O-methylherbarin and the azaanthraquinone scorpinone as well as three structurally related derivatives, O-phenethylherbarin and herbaridines A and B. All seven compounds exhibited cytotoxic activities against several cell lines.

Omphalotins E–I, oxidatively modified cyclic dodecapeptides, were isolated from mycelial extracts of the basidiomycete Omphalotus olearius, and their structures were determined by NMR spectroscopic and MS methods. Four of the five omphalotins contained an unprecedented N-hydroxylated tricyclic tryptophan derivative. All compounds exhibited strong and selective nematicidal activity against the plant pathogen Meloidogyne incognita with LD90 values between 2 and 5 μg mL–1. Cytotoxic activities were not detected up to 50 μg mL–1. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

1,2,3,4-Tetrahydroisoquinoline-1-carbonitriles can serve as starting materials for the one-pot synthesis of 5,6-dihydropyrrolo[2,1 a]isoquinolines and 1-benzyl-3,4-dihydroisoquinolines. The latter compounds were transformed to lamellarin G trimethyl ether and lamellarin U in short reaction sequences. This method allows the introduction of acid-sensitive protecting groups for the phenolic hydroxy functions which would be cleaved under the harsh conditions of the classical Bischler-Napieralski reaction.

The reaction of enaminones with 3-amino-2-cyanopent-2-enedinitrile can lead to an array of 12 possible products, depending on the reaction pathway and tautomerization. The use of 2D INADEQUATE and 15N NMR for the unambiguous structure elucidation of the reaction products is discussed in this manuscript. Copyright © 2012 John Wiley & Sons, Ltd.

Chrysoxanthone, an unusual heterodimer of blennolide A and 2-hydroxychrysophanol linked through a diaryl ether bridge, was isolated from mycelia of the ascomycete IBWF11-95A grown in submerged culture. Its structure was elucidated by two-dimensional NMR spectroscopy. The metabolite shows antibacterial activity against different species with MIC values between 2.5 and 20 μg/mL while also inhibiting the growth of several fungi.

The nonenolide hypocreolide A was isolated from culture filtrates of the ascomycete Hypocrea lactea. It exhibits moderate antimicrobial activity against various tested fungi and bacteria. Since neither the relative nor the absolute stereochemistry of the compound could be initially assigned, a stereochemically flexible total synthesis was developed. The two stereogenic centers were formed in high enantioselectivity and yield using transition metal catalyzed asymmetric reactions. While attempts to construct the ten-membered lactone in a ring-closing olefin metathesis gave disappointing results, a combination of cross metathesis and macrolactonization provided the title compound in nine steps and 12% overall yield.

Anthranicine, a cyclic hexapeptide containing anthranilic acid and pipecolic acid, was isolated from a mycophilic Acremonium species. The structure and stereochemistry of the compound featuring two D-configurated amino acids are discussed.

Omphalotins E–I, oxidatively modified cyclic dodecapeptides, were isolated from mycelial extracts of the basidiomycete Omphalotus olearius, and their structures were determined by NMR spectroscopic and MS methods. Four of the five omphalotins contained an unprecedented N-hydroxylated tricyclic tryptophan derivative. All compounds exhibited strong and selective nematicidal activity against the plant pathogen Meloidogyne incognita with LD90 values between 2 and 5 μg mL–1. Cytotoxic activities were not detected up to 50 μg mL–1. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Cultures of the ascomycete Dasyscyphus niveus have yielded two new tetracyclic dasyscyphin-type terpenoids (1 and 2), and their structures were elucidated by NMR spectroscopy and X-ray crystallography. The absolute configuration of dasyscyphin D (1) was determined by synthesis and NMR spectroscopy of diastereomeric MTPA esters. Both compounds inhibited the germination of conidia of Magnaporthe grisea at 25 microg/mL.

Anthranicine, a cyclic hexapeptide containing anthranilic acid and pipecolic acid, was isolated from a mycophilic Acremonium species. The structure and stereochemistry of the compound featuring two D-configurated amino acids are discussed.