Synthesis and antimicrobial/antioxidant evaluation of novel pyrimidine-based derivatives with pendant pyrazoles using vinamidinum salts

In the present study, synthesis of a variety of 5-bromo-4-methyl-2-substituted pyrimidines endowed with pyrazolyl substituent appended in C-4 position (7a-f) is described. These products are generated via treatment of 5-bromo-4- hydrazineyl-6-methyl-2-substituted pyrimidines (6a-f) and vinamidinum salt of (E)-N-(3-(dimethylamino)-2-phenylallylidene)-N-methylmethanaminium perchlorate (5) in good to excellent yields. The inhibitory and hydrogen-atom donating abilities of the synthesized products (7a-f) were assessed against nine pathogens including six bacterial strains (both Gram-negative and Gram-positive), three fungal strains and DPPH free radicals. Notable antioxidant properties were not observed with the products. IC50 values were in the range of 107.49-929.16 mu g ml(-1). The inhibition zone diameters of products at 10 mg ml(-1) concentrations were recorded in the range of 10.51-18.44 mm via disk diffusion method. 5-Bromo-4-methyl-6-pyrazolylpyrimidine (7e) containing 2-(4-methylpiperazin) substituent showed better antioxidant and antimicrobial effects than other products. It was effective on all the tested microbial strains except Staphylococcus epidermidis. All the synthesized pyrazolyl pyrimidines, especially (7e) can be used to disinfect the environment and treat infectious diseases. [GRAPHICS] .

Automated summary

In this study, a variety of 5-bromo-4-methyl-2-substituted pyrimidines with pyrazolyl substituent at C-4 position were synthesized. The products were obtained by treating 5-bromo-4-hydrazineyl-6-methyl-2-substituted pyrimidines and vinamidinum salt. The synthesized products were evaluated for their inhibitory and hydrogen-atom donating abilities against pathogens, showing notable antimicrobial effects for 5-bromo-4-methyl-6-pyrazolylpyrimidine with 2-(4-methylpiperazin) substituent (7e).