Structural basis for molecular recognition, theoretical studies and anti-bacterial properties of three bis-uracil derivatives

Three bis-pyrimidine compounds (1, 2 & 3) have been synthesized by the reaction of 6-[(dimethylamino)methyleneamino]-1,3-dimethyluracil with three different aldehydes viz. p-methoxybenzaldehyde, p-nitrobenzaldehyde, and 2-thiophenecarboxaldehyde in aqueous media in presence of ‘green surfactant’ followed by recrystallization in EtOH. The compounds are characterized by elemental analyses, NMR and single crystal X-ray diffraction. N–H⋯O hydrogen bonds and weak C–H⋯O interactions are the main non-bonding interactions in the molecular structures of the three compounds. Details of the synthesis, spectroscopic data and structures of the three compounds are presented. Furthermore, we have rationalized some relevant noncovalent interaction involving the aromatic moieties by means of DFT calculations. Finally, we have also analysed the anti-bacterial properties of compounds 1–3 and compared to Ofloxacin drug. The anti-bacterial activity has been tested against Klebsiella pneumoniae, Staphylococcus aureus and Pseudomonas aeruginosa. All compounds are found to possess from moderate to good anti-bacterial properties (MIC 25–100 μg/ml).