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[摘要]：Steriodal heterocyclic systems namely cholest-5-en-3-oxazolo and thiazologuinoxaline 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, H-1 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. (C) 2007 Elsevier Masson SAS. All rights reserved. |
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