A non-covalent self-assembled chiral alanyl aminopyridine ligand exhibits supramolecular chirality in solution, independent of the organic solvent used. The supramolecular chirality of the assemblies is completely inverted by complexation to zinc ions. To date, such a supramolecular metal-ligand system has not been reported in the literature.

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The conformation of the peptidoglycan monomer (PGM) from Brevibacterium divaricatum was determined in aqueous solution using a combined approach by 2D NMR spectroscopy, restrained simulated annealing, and molecular dynamics (MD) calculations. MD simulations in water without experimental constraints provided insights into the structure and dynamics of this glycopeptide. Hierarchical cluster analyses for conformer classifications were performed using a global molecular shape descriptor (CoMFA steric fields). Principal component analysis was subsequently employed to extract orthogonal principal conformational properties. Correlated dihedral angle mobilities were identified using a dynamic cross correlation map. The calculation of radial distribution functions for all polar protons of the molecule leads to additional information about the solvation of PGM in a protic solvent, while autocorrelation functions for dihedral angle fluctuations were used to monitor dynamic processes in different regions. From simulated annealing, a set of 11 conformers was obtained, all characterized by a well-defined extended N-terminal peptide part additionally stabilized by the bound disaccharide; the C-terminal part, on the other hand, exhibits more conformational flexibility in agreement with experimental data and MD simulations. The disaccharide conformation is in agreement with the conformational minimum computed for the model disaccharide 3-O-Me-4-O-βGlcNAc-αMurNAc using various force fields. Not only the interglycosidic bond but also the glycopeptide linkage exists in a single, well-defined conformation, for which no conformational changes can be detected during the MD simulations. In contrast, conflicting experimental data for the N-acetyl group of GlcNAc could be explained using a conformer population analysis based on ROE intensities and coupling constants accounting for a conformational equilibrium with one dominantly populated rotamer.

A new approach to benzo[f]quinoline derivatives has been found by an effective formal [4 + 2] photocycloaddition process from novel aryl-substituted o-vinylstyryl-2-oxazoles. All of the o-vinylstyryl-2-oxazoles were synthesized by a multicomponent Wittig reaction from the diphosphonium salt of α,α'-o-xylene dibromide, formaldehyde, and 5-tolyl-, 4-phenyl-5-methyl-, and 4,5-diphenyloxazole-2-carbaldehydes. TD-DFT calculations revealed that the intramolecular photocyclization in 2-(2-vinylstyryl)oxazoles to form benzo[f]quinoline derivatives proceeds on the S1 PES via a stepwise pathway, namely by 10π followed by 6π ring closure. On that path the existence of an S0/S1 conical intersection was indicated. The reactivity of the photocyclization steps depends on the substitution pattern at positions 4 and 5 of the oxazole ring, where the aryl group in position 5 deactivates the reaction.

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