Khan Salman A
Department of Chemistry, Punjabi University, Patiala 147002, Punjab, India.
Eur J Med Chem. 2008 Sep;43(9):2040-4. doi: 10.1016/j.ejmech.2007.12.008. Epub 2007 Dec 23.
Steriodal heterocyclic systems namely cholest-5-en-3-oxazolo and thiazoloquinoxaline have been synthesized via the reaction of cholest-5-en-3-one semicarbazone/thiosemicarbazone with 2,3-dichloroquinoxaline at 80 degrees C in high yield. Cholest-5-en-3-one semicarbazone is obtained by the condensation of cholest-5-en-3-one with semicarbazide in the presence of AcONa in ethanol and cholest-5-en-one thiosemicarbazone is obtained by the condensation of cholest-5-en-3-one with thiosemicarbazide in ethanol in the presence of a few drops of HCl. The structures of these compounds were evident by elemental analysis, IR, 1H NMR and FAB mass spectral analysis. These synthesized compounds were investigated for antibacterial activity first by the disk-diffusion assay against two Gram-positive and two Gram-negative bacteria and then the minimum inhibitory concentration (MIC) of these compounds were determined and the results were compared with the standard drug Amoxicillin. The results showed that these compounds oxazolo/thiazoloquinoxaline are better antibacterial agents as compared to the standard drug Amoxicillin.
甾体杂环体系，即胆甾-5-烯-3-恶唑并噻唑并喹喔啉，已通过胆甾-5-烯-3-酮缩氨基脲/硫代缩氨基脲与2,3-二氯喹喔啉在80℃下反应高产率合成。胆甾-5-烯-3-酮缩氨基脲是通过胆甾-5-烯-3-酮与氨基脲在乙醇中于醋酸钠存在下缩合得到的，而胆甾-5-烯-3-酮硫代缩氨基脲是通过胆甾-5-烯-3-酮与硫代氨基脲在乙醇中于几滴盐酸存在下缩合得到的。这些化合物的结构通过元素分析、红外光谱、1H核磁共振和快原子轰击质谱分析得以明确。首先通过对两种革兰氏阳性菌和两种革兰氏阴性菌的纸片扩散法研究了这些合成化合物的抗菌活性，然后测定了这些化合物的最低抑菌浓度（MIC），并将结果与标准药物阿莫西林进行了比较。结果表明，与标准药物阿莫西林相比，这些恶唑并/噻唑并喹喔啉化合物是更好的抗菌剂。
