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Pyrazolones derivatives are known for their pharmaceutical and therapeutic activities. In this regard, some new pyrazolone derivatives have been synthesized using cyclocondensation, nucleophilic substitution, and alkylation reactions. Their corresponding structures were elucidated using X-ray diffraction and NMR spectroscopic techniques. The experimental spectral data were compared with the predicted ones obtained at the B3LYP/6-311++G(d,p) level of theory. Geometrical parameters and chemical shifts are relatively well reproduced with correlation coefficients higher than 90%. The intercontacts in crystal units were investigated by the analysis of their corresponding Hirshfeld surfaces and fingerprint maps, which reveal that the major contacts are found for H...H intercontacts. Finally, the inhibition efficiency of the novel pyrazolone derivatives as SARS-CoV-2 Mpro is estimated by determining their binding affinities into the binding site of SARS-CoV-2 Mpro. The docking results reveal that the current pyrazolone derivatives may act as potent inhibitors of SARS-CoV-2 Mpro and that their inhibition efficiency may be strongly influenced by the substituted functional groups of pyrazolone moiety. Synthesis of new 4-Substituted Pyrazolone derivatives Good correlations are obtained between the spectra and X-ray data with the predicted ones. Hirshfeld surface analysis is used to analyze intermolecular interaction. 3D molecular structure is characterized using x-Ray and spectroscopic techniques. Interactions for of the newly synthesized compounds 2b, 3b, 3a, and 4 docked SARS-CoV-2 Mpro/PDB: 6LU7-A chain protein. [ABSTRACT FROM AUTHOR]

The title compound, C 16 H 17 N 3 O 3 , is racemic as it crystallizes in a centrosymmetric space group ( P ), although the trans disposition of substituents about the central C-C bond is established. The five- and six-membered rings are oriented at a dihedral angle of 75.88 (8)°. In the crystal, N-H⋯N hydrogen bonds form chains of mol-ecules extending along the c -axis direction that are connected by inversion-related pairs of O-H⋯N into ribbons. The ribbons are linked by C-H⋯π(ring) inter-actions, forming layers parallel to the ab plane. A Hirshfeld surface analysis indicates that the most important contributions for the crystal packing are from H⋯H (45.9%), H⋯N/N⋯H (23.3%), H⋯C/C⋯H (16.2%) and H⋯O/O⋯H (12.3%) inter-actions. Hydrogen bonding and van der Waals inter-actions are the dominant inter-actions in the crystal packing. The volume of the crystal voids and the percentage of free space were calculated to be 100.94 Å 3 and 13.20%, showing that there is no large cavity in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicates that the stabilization is dominated by the electrostatic energy contributions in the title compound. Moreover, the DFT-optimized structure at the B3LYP/6-311 G(d,p) level is compared with the experimentally determined mol-ecular structure in the solid state. The HOMO-LUMO behaviour was elucidated to determine the energy gap., (© Ait Elmachkouri et al. 2024.)

In the title mol-ecule, C 8 H 7 NO 3 S, the nitro-gen atom has a planar environment, and the thia-zine ring exhibits a screw-boat conformation. In the crystal, corrugated layers of mol-ecules 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) inter-actions. The layers are connected by additional C-H⋯O hydrogen bonds and π-stacking inter-actions. 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%) inter-actions. The volume of the crystal voids and the percentage of free space were calculated as 75.4 Å 3 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 mol-ecular structure in the solid state. The HOMO-LUMO behaviour was elucidated to determine the energy gap., (© Irrou et al. 2023.)