In this work, ribonucleoside products have been prepared by employing stannic tetrachloride (SnCl4) and natural phosphate as catalysts. The obtained result suggests that this catalyst facilitates the reactions of ribonucleoside-like products in a stereo-controlled manner, exhibiting β-selectivity when reacting with trimethylsilyl uracil, the ribonucleosides derivatives were obtained in suitable yields. In addition, we have performed the molecular docking analysis, demonstrated that the synthesized compounds have potential for antiviral activity against the omicron variant of coronavirus, and the D3, D4, E and F products have a higher binding energy than the molnupiravir drug, indicating that these products may be a probable drugs for the omicron variant.

Application of the Molecular Electron Density Theory (MEDT) for the exploration of the [3+2] cycloaddition processes between methyl propynoate 1 and difluoromethyldiazomethane T-1, have been implemented using the DFT/B3LYP/6-311(d,p) level of theory. According to an examination of conceptual DFT indices, difluoromethyldiazomethane (T-1) participates in this reaction as a nucleophile, while methyl propynoate (1) should be considered as an electrophile. This cyclization is regiospecific, as evidenced by the activation and reaction energies, this agrees with the experiment's findings. It was discovered throughout ELF analysis that analyzed [3+2] cycloaddition is realised by a two-step mechanism. In addition, study of interactions of the products studied in this paper with the protein protease Covid-19 (PDB ID: 7R98) were carried out, by means of molecular docking study). The results indicate that the occurrence of the transfer of the proton to the nitrogen atom, increases the affinity of these products to the protein (CA32-F1 and CA32-F2).