Synthesis, Identification, and Antibacterial Effect Assessment of Some New 1,4-Thiazepines, Derived from Substituted Diphenyl Acrylamides and Diphenyl Dienones

Some new 1,4-thiazepine derivatives (J16-J30) have been successfully synthesized through the reaction between each of diphenyl acryl amides (J1-J10) and diphenyl dienones (J11-J15) with ortho-mercapto aniline. The reaction was performed in an alkaline medium using ethanol as a solvent. The diphenyl acryl amides were prepared from the condensation reaction of para-substituted acetanilides with different para benzaldehydes, while para-substituted benzaldehydes were reacted with acetone to produce the diphenyl dienones. All the prepared compounds have been identified, using visible and ultraviolet radiation spectrum, and infrared spectrum. Some of the new synthesized compounds have been diagnosed and confirmed their structures by proton and carbon nuclear magnetic resonance spectrum (1H-NMR and 13C-NMR, respectively). The purity of prepared compounds was confirmed by relying on thin-layer chromatography (TLC) results. The biological effect of these derivatives was assessed against certain types of gram-positive bacteria (Streptococcus Pneumonia and Staphylococcus Aureus) and gram-negative bacteria (Escherichia Coli, Pseudomonas Aeruginosa, and Proteus Moralities). The results showed a high antibacterial effect towards both types of the used bacteria at high concentrations, while the prepared compounds behaved differently at low concentrations. The results indicated that most of new thiazepines revealed a high antibacterial effect towards both types of the tested bacteria at high concentrations (100 mg/mL), while behaved oppositely at low concentrations (10 and 50 mg/mL). This is related to high concentration effect resulting in an increase for inhibition zone diameter. The highest antibacterial effect was observed for compounds (J17, J19, J21, J24, J25, J26, J28, and J30) at 100 mg/mL. One of the reasons could be the presence of halogenes and nitro groups compared to the other compounds as a result of electron withdrawal groups role.