New mercaptopyrimidine derivatives synthesized with expected antimicrobial and antioxidant properties and theoretical study

In this elucidation, we synthesized different heterocyclic containing the thiopyrimidine nuclei, through the esterification of 2-mercapto pyrimidine with ethyl chloroacetate to give the corresponding ethyl 2-(pyrimidine-2-ylthio)acetate. Treatment of the ester compound 3 with hydrazine hydrate gave 2-(pyrimidin-2-ylthio)acetohydrazide 4 which acts as the building block for the synthesis of different heterocycles. Firstly the reaction with phenylisothiocyanate to afford the hydrazinecarbothioamide derivative 6 which cyclized in the presence of acidic and basic medium to give ((pyrimidin-2-ylthio)methyl)-1,3,4-thiadiazol-2-amine and triazole derivatives 7,8; respectively. Additionally, the formation of 2-((hydrazinylmethylthio)pyrimidine10 which is reacted with galactose ring to give methyl)hydrazinyl)hept‑6-ene-1,2,3,4,5-pentayl pentaacetate derivative 13 in the presence of acetic acid. All the synthesized compounds were investigated through spectral analysis of ¹HNMR, ¹³CNMR, FT-IR, and mass spectrum. Moreover, the antimicrobial activity of the samples was examined in vitro on both gram-positive and gram-negative bacteria and fungi. Compound 13 displayed a strong efficiency against Bacillus cereus, Staphylococcus aureus, and Pseudomonas aeruginosa, All tested heterocycles exhibited remarkable inhibitory effects against the other pathogenic organisms. Antifungal screening of synthesized heterocycles varied and ranged from no activity to strong activity against Fusarium solani and demonstrated remarkably strong inhibitory activity against Candida albicans. Among all the heterocycles showed high antioxidant activity. These biological results were confirmed through molecular docking analysis utilizing different proteins. Furthermore, the optimization of these compounds was utilized through the DFT/B3LYP/6–311(G) basis set and elucidation of their descriptors and enhanced the biological activities