Starch, an abundant and low-cost plant-based glucopolymer, has great potential to replace carbon-based polymers in various materials. In order to optimize its functional properties for bioplastics applications chemical groups need to be introduced on the free hydroxyl groups in a controlled manner, so an understanding of the resulting structure-properties relationships is therefore essential. The purpose of this work was to study the multiscale structure of highly-acetylated (degree of substitution, 0.4 < DS ≤ 3) and etherified starches by using an original combination of experimental strategies and methodologies. The molecular structure and substituents repartition were investigated by developing new sample preparation strategies for specific analysis including Asymmetrical Flow Field Flow Fractionation associated with Multiangle Laser Light Scattering, Nuclear Magnetic Resonance (NMR), Raman and Time of Flight Secondary Ion Mass spectroscopies. Molar mass decrease and specific ways of chain breakage due to modification were pointed out and are correlated to the amylose content. The amorphous structuration was revealed by solid-state NMR. This original broad analytical approach allowed for the first time a large characterization of highly-acetylated starches insoluble in aqueous solvents. This strategy, then applied to characterize etherified starches, opens the way to correlate the structure to the properties of such insoluble starch-based materials.

Quinolones represent one of the largest classes of synthetic antibiotics used in both human and veterinary medicine. Since the discovery of nalidixic acid, a substantial body of research has been carried out on quinolones, resulting in the synthesis of several quinolone derivatives with exceptional pharmacology. In addition to their antibacterial action, quinolones have a broad spectrum of diverse biological activities. In this regard, the present review examines the literature of recent years describing synthesis protocols, reactivity and biological properties, with particular emphasis on the antibacterial, antimalarial, antitrypanosomal, antileishmanial, antiviral and anticancer activities of this famous class of molecules. Finally, this review highlights the potential of quinolones as preferred pharmacophores in medicinal chemistry. The aim is to highlight the innovative aspects of the rational design of new therapeutic agents with this structural motif, in the face of emerging antibiotic resistance and the urgent need for new active molecules.

In the title molecule, C₁₄H₁₁NO₃, the dihydroquinoline core deviates slightly from planarity, indicated by the dihedral angle of 1.07 (3)° between the two six-membered rings. In the crystal, layers of molecules almost parallel to the bc plane are formed by C—H...O hydrogen bonds. These are joined by π–π stacking interactions. A Hirshfeld surface analysis revealed that the most important contributions to the crystal packing are from H...H (36.0%), H...C/C...H (28.9%) and H...O/O...H (23.5%) interactions. The evaluation of the electrostatic, dispersion and total energy frameworks indicates that the stabilization is dominated by the dispersion energy contribution. Moreover, the molecular structure optimized by density functional theory (DFT) at the B3LYP/6-311G(d,p) level is compared with the experimentally determined molecular structure in the solid state. The HOMO–LUMO behaviour was elucidated to determine the energy gap.

In the title molecule, C₈H₇NO₃S, the nitrogen atom has a planar environment, and the thiazine ring exhibits a screw-boat conformation. In the crystal, corrugated layers of molecules parallel to the ab plane are formed by N—H...O and C—H...O hydrogen bonds together with C—H...π(ring) and S=O...π(ring) interactions. The layers are connected by additional C—H...O hydrogen bonds and π-stacking interactions. Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are from H...O/O...H (49.4%), H...H (23.0%) and H...C/C...H (14.1%) interactions. The volume of the crystal voids and the percentage of free space were calculated as 75.4 ų and 9.3%. Density functional theory (DFT) computations revealed N—H...O and C—H...O hydrogen-bonding energies of 43.3, 34.7 and 34.4 kJ mol⁻¹, respectively. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the stabilization is dominated via the electrostatic energy contribution. Moreover, the DFT-optimized structure at the B3LYP/ 6–311 G(d,p) level is compared with the experimentally determined molecular structure in the solid state. The HOMO–LUMO behaviour was elucidated to determine the energy gap.