Some heterocyclic systems namely cholest-5-en-7-thiazolo[4,5-b]quinoxaline-2-yl-hydrazone] were synthesized by the reaction of cholest-5-en-7-one-thiosemicarbazone with 2,3-dichloroquinoxaline at 80 degrees C in high yield. The thiosemicarbazone derivatives were obtained by the condensation of the thiosemicarbazide with steroidal ketones. All the compounds have been characterized by means of elemental analyses, IR, 1H NMR and mass spectroscopic data. The in vitro antibacterial activity was evaluated by disk diffusion method and then the minimum inhibitory concentration (MIC) of compounds was determined against the culture of Escherichia coli. The results were compared with the standard drug chloramphenicol. The results showed that compounds 7 and 8 are better antibacterial agents as compared to chloramphenicol.
