Synthesis of steroidal thiazolidinones as antibacterial agents based on the in vitro and quantum chemistry calculation

Steroidal thiazolidinone derivatives were prepared from the reaction of steroidal thiosemicarbazones with ethyl bromoacetate in dioxane. Steroidal thiosemicarbazones were prepared by reacting thiosemicarbazide with steroidal ketones. The structures of these compounds were elucidated by IR, 1HNMR, 13CNMR, and mass spectral study, and their purities were confirmed by elemental analyses. The antibacterial activities of these compounds were evaluated by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria, and then the minimum inhibitory concentration of compounds were determined. The results showed that steroidal thiazolidinone derivatives are better in inhibiting growth as compared with steroidal thiosemicarbazone derivatives of both types of the bacteria. Compounds 7 and 8 are better antibacterial agents as compared with standard drug, Amoxicillin. Based on the quantum chemistry calculation at the DFT/6-31G* level, the frontier molecular orbitals and electrostatic potential of compounds 7 and 8 were also discussed.