title: Synthesis, characterization and in vitro antibacterial activity of new steroidal thiazolo quinoxalines.
abstract: Herein, we report the synthesis of different steroidal thiazolo quinoxaline derivatives as antibacterial agents against Escherichia coli. Steroidal ketone thiosemicarbazones (4-6) were obtained from corresponding ketones (1-3) by refluxing with thiosemicarbazide. The thiosemicarbazones on reaction with 2,3-dichloroquinoxalines at 80 degrees C gives 3beta-acetoxy-5alpha-cholestan-6-[thiazolo(4,5-b)quinoxaline-2-yl-hydrazone] (7), 3beta-chloro-cholestan-6-[thiazolo(4,5-b)quinoxaline-2-yl-hydrazone] (8), and 5alpha-cholestan-6-[thiazolo(4,5-b)quinoxaline-2-yl-hydrazone] (9). The structures of the compounds were evident by elemental, IR, (1)H NMR and FAB mass spectral analyses. The antibacterial activities of these compounds were evaluated by disk diffusion method against the culture of E. coli and the results were compared with the standard drug amoxicillin. The results reveal that the compounds are better antibacterial agents as compared to amoxicillin. Among all the three compounds (7-9), compound 8 showed better zone of inhibition.
authors.affiliation: Department of Chemistry, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India.
authors.forename: Salman Ahmad
authors.initials: SA
authors.lastname: Khan
authors.forename: Kishwar
authors.initials: K
authors.lastname: Saleem
authors.forename: Zaheer
authors.initials: Z
authors.lastname: Khan
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D002776:Cholestanes / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects; D006835:Hydrazones / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D011810:Quinoxalines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship; D013844:Thiazoles / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D002776:Cholestanes; D006835:Hydrazones; D011810:Quinoxalines; D013844:Thiazoles