Hermansones A and B: Bioactive naphthazarin congeners from the European crust fungus Hermanssonia centrifuga.

Two previously undescribed naphthazarins named hermansones A (1) and B (2), were isolated from the wood-decaying basidiomycete Hermanssonia centrifuga. The study presents the first report of natural products from the species. The structures of the secondary metabolites were elucidated through NMR spectroscopy and mass spectrometry.

Aplospojaveedins A-C, unusual sulfur-containing alkaloids produced by the endophytic fungus using OSMAC strategy.

Three sulfur-containing alkaloids aplospojaveedins A-C (1-3) with a hitherto undescribed carbon skeleton comprising octahy-dronaphthalene, , -unsaturated lactam and glycine-cysteine moieties were isolated from . Their structures were elucidated by 1D and 2D NMR spectroscopy, HR-MS, X-ray diffraction analysis, DFT-NMR and TDDFT-ECD calculations. A plausible biosynthetic pathway and putative targets are described.

VCD Analysis of Axial Chirality in Synthetic Stereoisomeric Biaryl-Type -Isochroman Heterodimers with Isolated Blocks of Central and Axial Chirality.

Optically active heterodimeric 5,5'-linked -isochromans, containing a stereogenic -trisubstituted biaryl axis and up to four chirality centers, were synthesized stereoselectively by using a Suzuki-Miyaura biaryl coupling reaction of optically active isochroman and 1-arylpropan-2-ol derivatives, providing the first access to synthetic biaryl-type isochroman dimers. Enantiomeric pairs and stereoisomers up to seven derivatives were prepared with four different substitution patterns, which enabled us to test how OR, ECD, and VCD measurements and DFT calculations can be used to determine parallel central and axial chirality elements in three isolated blocks of chirality. In contrast to natural penicisteckins A-D and related biaryls, the ECD spectra and OR data of (a) and (a) atropodiastereomers did not reflect the opposite axial chirality, but they were characteristic of the central chirality.

Dactylfungins and Tetralones: Bioactive Metabolites from a Nematode-Associated .

A chemical investigation of , isolated from cysts of the plant parasitic nematode , affored three dactylfungin derivatives (-) and three tetralone congeners (-). Dactylfungin C (), laburnicolin (), and laburnicolenone () are previously undescribed natural products. Chemical structures of the isolated compounds were determined based on 1D and 2D NMR spectroscopic analyses together with HR-ESI-MS spectrometry and comparison with data reported in the literature.

Testing the Simplified Molecular Dynamics Approach to Improve the Reproduction of ECD Spectra and Monitor Aggregation.

A simplified molecular-dynamics-based electronic circular dichroism (ECD) approach was tested on three condensed derivatives with limited conformational flexibility and an isochroman-2-chromene hybrid, the ECD spectra of which could not be precisely reproduced by the conventional ECD calculation protocol. Application of explicit solvent molecules at the molecular mechanics (MD) level in the dynamics simulations and subsequent TDDFT-ECD calculation for the unoptimized MD structures was able to improve the agreements between experimental and computed spectra. Since enhancements were achieved even for molecules with limited conformational flexibility, deformations caused by the solvent molecules and multitudes of conformers produced with unoptimized geometries seem to be key factors for better agreement.