Synthesis and in vitro antibacterial activity of novel steroidal (6R)-spiro-1,3,4-thiadiazoline derivatives

Article abstract of DOI:10.1002/jhet.1014

Novel steroidal (6R)-spiro-1,3,4-thiadiazoline derivatives were synthesized by the cyclization of steroidal thiosemicarbazones with acetic anhydride, screened in vitro against antibacterial activity using disc-diffusion method and the minimum inhibitory concentration. The results showed that steroidal thiadiazoline derivatives exhibited better antibacterial activity than the steroidal thiosemicarbazone derivatives. Chloro and acetoxy substituents on the 3β-position of the steroidal thiadiazoline ring increased the antibacterial activity. Among all the compounds, compound 7 and 8 were found better inhibitors of both types of bacteria (Gram-positive and Gram-negative) as compared to the respective drug amoxicillin. All the synthesized compounds were well characterized by spectroscopic methods such as IR, ¹H-NMR, ¹³C-NMR mass, and elemental analysis and their stereochemistry was also discussed.