Synthesis, characterization and evaluation of thiopyrimidine derivatives as possible antimicrobial agents

Abstract

A series of new thiopyrimidine derivatives have been synthesized via the reaction of Chalcones 3a-c with thiourea to give the corresponding pyrimidine thiones 4a-c. S-alkylation of pyrimidine thiones have resulted in novel 4,6-diaryl-2-alkyl thiopyrimidine 5a-i derivatives. Molecular properties like number of hydrogen bond acceptors, number of hydrogen bond donors, volume, polar surface area, molar refractivity, number of rotatable bonds and drug likeness for synthesized compounds have been predicted by using different softwares such as Molinspiration, Molsoft and Chemsketch. The newly synthesized 4,6-diaryl-2-alkyl thiopyrimidine derivatives 5a-i have been evaluated for their possible anti-microbial activity. Compounds 5b, 5d and 5e have revealed significant activity against E. coli, P. aerugenosa (Gram +ve) and B. subtilis, S. aureus (Gram −ve) species while compounds 5a, 5c, 5f-i are moderately active as compared to the standard drug Ciprofloxacin. Compounds 5c and 5g show potent anti-fungal activity against Penicillium species amongst the series in comparison to the standard Fluconazole.