The three-component condensation reaction of 4-methylbenzaldehyde with acetophenone and urea in the presence of CF₃COOH was investigated and as a result, 4-phenyl-6-(p-tolyl)pyrimidin-2(1H)-one (PPTP) was synthesized. The structure was determined by single crystal X-rays diffraction analysis which inferred that the PPTP crystallized in monoclinic crystal system with space group P2₁/c. The dihedral angles between the aromatic rings indicate that the molecule is non-planar. The crystal packing is mainly stabilized by N–H⋯O and C–H⋯O bonding which is further stabilized by off-set π⋯π stacking interactions. The supramolecular assembly is further investigated by Hirshfeld surface analysis. The mechanical behaviour is predicted by the void analysis Moreover, the computational study is carried out for finding the interaction energy between molecular pair by using B3LYP/6-31G(d,p) electron density model. The study inferred the role of various types of interaction energies in stabilizing the crystal packing.

3,4-Dihydropyrimidinones (-thiones) were prepared by ternary condensation of various aromatic aldehydes with ethyl acetoacetate and urea (thiourea) in the presence of trichloroacetic acid in ethanol.

It has been found that CF₃COOH catalyzes the Knoevenagel condensation reaction of 5-bromo-2-hydroxybenzaldehyde and ethyl cyanoacetate. Consequently, the 6-bromo-2-oxo-2H-chromene-3-carbonitrile (BOCC) compound has been synthesized. The structure was proved by single crystal X-rays diffraction analysis. The asymmetric unit contained two identical molecules A and B which are different with respect to crystallography. The crystal packing is mainly stabilized by C–H⋯N and C–H⋯O bonding which is further stabilized by C–N⋯π and off-set π⋯π stacking interactions. Hirshfeld surface analysis is employed for the further exploration of the intermolecular interactions. Enrichment ratio is computed for the interatomic contacts to find the tendency of the contacts to form the crystal packing interactions. The void analysis is performed to predict the mechanical behaviour. Furthermore, the computational study is performed for finding the interaction energy between molecular pair by using B3LYP/6-31G(d,p) electron density model. The study inferred the role of various types of interaction energies in stabilizing the molecular pair.

Although antimicrobial resistance before the Covid-19 pandemic is a top priority for global public health, research is already ongoing on novel organic compounds with antimicrobial and antiviral properties in changing medical environments in connection with Covid 19. Thanks to the Biginelli reaction, which allows the synthesis of pyrimidine compounds, blockers of calcium channels, antibodies, antiviral, antimicrobial, anti-inflammatory, or antioxidant therapeutic compounds were investigated. In this paper, we aim to present Biginelli's synthesis, its therapeutic properties, and the structural–functional relationship in the test compounds that allows the synthesis of antimicrobial compounds. Both the DFT and TD-DFT computations of spectral data, molecular orbitals (HOMO, LUMO) analysis, and electrostatic potential (MEP) surfaces are carried out as an add-on to synthetic research. Hirshfeld surface analysis was also used to segregate the different intermolecular hydrogen bonds involved in the molecular packing strength. Natural Bond Orbital (NBO) investigation endorses the existence of intermolecular interactions mediated by lone pair, bonding, and anti-bonding orbitals. The dipole moment, linear polarizability, and first hyperpolarizabilities have been explored as molecular parameters. All findings based on DFT exhibit the best consistency with experimental findings, implying that synthesized molecules are highly stable. To better understand the binding mechanism of the SARS-CoV-2 M^pro, we performed molecular docking, molecular dynamics (MD) simulations, and binding free energy calculations.