The method previously used to detect structural features of piracetam, which can be considered as preconditions for a crystal phase to crystal phase polymorphic transition, was applied to study the structure of ibuprofen, which was found to be stable under the influence of pressure. Analysis of the pairwise interaction energies between molecules has classified the ibuprofen structure as a layered packing of dimeric building units. The shear deformation modeling of strongly bound layers in the crystal structure under ambient pressure determined the [001] crystallographic direction along the (100) crystallographic plane as the only probable direction of crystal structure deformation. Under ambient pressure, the interaction energies between the mobile and fixed parts of the model system proved to be negative during the displacement in one crystallographic translation. The shift energy barrier of 10.1 kcal mol⁻¹ for such deformation was calculated using the B97D3/cc-PVDZ method. An increase in pressure results in the appearance of a region with positive interaction energies in the shift energy profile and a sharp increase in the shift energy barrier. In contrast to piracetam crystals, the increase in energy does not lead to the polymorphic transition of the ibuprofen crystals, but results in the appearance of additional C–H⋯π and C–H⋯O intermolecular interactions and their strengthening. This can be explained by the absence of a local minimum in energy near the starting point in the model system. The smallest displacement of the mobile part to the fixed one leads to a decrease in the interaction energy.

The title compound, C₂₄H₂₆N₂O₄S, can be obtained via two synthetic routes. According to our investigations, the most suitable way is by the reaction of ethyl 2-bromoacetate with sodium tosylsulfinate in dry DMF. It was crystallized from methanol into the monoclinic P2₁/n space group with a single molecule in the asymmetric unit. Hirshfeld surface analysis was performed to define the hydrogen bonds and analysis of the two-dimensional fingerprint plots was used to distinguish the different types of interactions. Two very weak non-classical C—H...O hydrogen bonds were found and the contributions of short contacts to the Hirshfeld surface were determined. Molecules form an isotropic network of intermolecular interactions according to an analysis of the pairwise interaction energies. A molecular docking study evaluated the interactions in the title compound with the active centers of macromolecules of bacterial targets (Staphylococcus aureus DNA Gyrase PDB ID: 2XCR, Mycobacterium tuberculosis topoisomerase II PDB ID: 5BTL, Streptococcus pneumoniae topoisomerase IV PDB ID: 4KPF) and revealed high affinity towards them that exceeded the reference antibiotics of the fluoroquinolone group.

C₄H₈N₈OS₂, triclinic, P 1 ‾ (no. 2), a = 7.4377(5) Å, b = 7.5032(5) Å, c = 10.0964(6) Å, α = 91.481(5)°, β = 108.906(5)°, γ = 110.678(6)°, V = 492.41(6) ų, Z = 2, R_gt(F) = 0.0653, wR_ref(F²) = 0.1888, T = 293 (2) K.

The title compound, C₃₀H₃₃N₄O₂F, can be obtained via a two-step synthetic scheme involving 1-benzyl-6-fluoro-4-oxo-7-(piperidin-1-yl)-1,4-dihydroquinoline-3-carbonitrile as a starting compound that undergoes substitution with hydroxylamine and subsequent cyclization with 4-methylcyclohexane-1-carboxylic acid. It crystallizes from 2-propanol in the triclinic space group P\overline{1} with a molecule of the title compound and one of 2-propanol in the asymmetric unit. After the molecular structure was clarified using NMR and LC/MS, the molecular and crystalline arrangements were defined with SC-XRD. A Hirshfeld surface analysis was performed for a better understanding of the intermolecular interactions. One strong (O—H...O) and three weak [C—H...F (intramolecular) and two C—H...O] hydrogen bonds were found. The contributions of short contacts to the Hirshfeld surface were estimated using two-dimensional fingerprint plots showing that O...H/H...O, C...H/H...C and C...C contacts are the most significant for the title compound and O...H for the 2-propanol. The crystal structure appears to have isotropically packed tetramers containing two molecules of the title compound and two molecules of 2-propanol as the building unit according to analysis of the distribution of pairwise interaction energies. A molecular docking study was carried out to evaluate the interactions of the title compound with the active centers of macromolecules corresponding to viral targets, namely, anti-hepatitis B activity [HBV, capsid Y132A mutant (VCID 8772) PDB ID: 5E0I] and anti-COVID-19 main protease activity (PDB ID: 6LU7). The data obtained revealed a noticeable affinity towards them that exceeded that of the reference ligands.