Design, synthesis, and biological evaluation of thiourea and guanidine derivatives of pyrimidine-6-carboxylate

Two new series of methyl 7-methyl-5-(substituted-phenyl)-3,5-dihydro-2H—substituted [3,2-α]pyrimidine-6-carboxylate derivatives of thiourea and guanidine were synthesized. These compounds were characterized and evaluated for their antibacterial activity against Staphylococcus aureus, Bacillussubtilis, Escherichiacoli, and antifungal Aspergillus niger and Candida albicans and free radical scavenging activity using DPPH reagent method. Compound 7f was found to be the most active antibacterial and antifungal agent comparable to the standard drugs ciprofloxacin and fluconazole. Further, the compounds 5e, 7g, and 7h were also found to have significant antimicrobial activity. Compound 5a was found to be the most active antioxidant among all the targeted compounds, while compounds 5b, 5g, 7b, and 7f also had significant antioxidant activity compared to standard ascorbic acid.