Design and Evaluation of Antimicrobial Activity of New Pyrazoles, 1,2,4-Triazole and 1,3,4-Thiadiazol Derivatives Bearing 1,4-Dihydroquinoxaline Moiety
Nadia Ali Ahmed Elkanzia, b, 1, Hajer Hrichiac
aChemistry Department, College of Science, Jouf University, P.O. Box: 2014, Sakaka, Saudi Arabia; bChemistry Department, Faculty of Science, Aswan University, P.O. box 81528, Aswan, Egypt; cNational Institute of Applied Sciences and Technology, Carthage University, Centre Urbain Nord, B.P.No676, 1080 Tunis Cedex, Tunisia
Received 03.09.2019; revised 30.09.2019; accepted 01.10.2019
Abstract––An effective method for synthesizing a series of fifteen new compounds Ethyl 3-(2-(3-amino-1,4-dihydroquinoxaline-2-carbonyl)hydrazono)butanoate (II), 3-amino-N'-benzylidene-1,4-dihydroquinoxaline-2-carbohydrazide dérivatives (IV-VI), phenyl)-4-oxothiazolidin-3-yl)-1,4-dihydroquinoxaline-2-carboxamide derivatives (VII-IX), 3-(3-amino-1,4-dihydroquinoxalin-2-yl)-5H-[1,2,4]triazolo[3,4-a]isoindol-5-one (X), 1,4-dihydroquinoxaline-2-carbonyl)-N-substituted hydrazine carbothioamide (XI-XII), 5-(3-amino-1,4-dihydroquinoxalin-2-yl)-4-substituted -4H-1,2,4-triazole-3-thiol (XIII-XIV) and 5-(3-amino-1,4-dihydroquinoxalin-2-yl)-N-substituted -1,3,4-thiadiazol-2-amine (XV-XVI) based on 1,4-dihydroquinoxaline moiety in 60-85% yields starting from reaction of hydrazide 3-Amino-1,4-dihydroquinoxaline-2-carbohydrazide (I) with ethyl acetoacetate has been proposed. The designed compounds have been successfully screened in vitro for their antibacterial and antifungal activities. Structural identifications of the obtained products have been carried out by spectroscopic techniques including FTIR, 1H NMR, 13C NMR, and mass spectroscopy. The relation between the structure of the synthesized compounds and their activity against selected bacteria and fungi was studied and favorable results were obtained. The majority of tested compounds showed moderate antibacterial activities except compound 3-amino-N-(2-(4-chlorophenyl)-4-oxothiazolidin-3-yl)-1,4-dihydroquinoxaline-2-carboxamide (VIII) that notably exhibited the most potent antibacterial activity against the tested Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa bacteria. Further antifungal studies indicated that the compounds Ethyl 3-(2-(3-amino-1,4-dihydroquinoxaline-2-carbonyl)hydrazono) butanoate (II), 3-amino-N-(2-(4-chlorophenyl)-4-oxothiazolidin-3-yl)-1,4-dihydroquinoxaline-2-carboxamide (VIII), 3-amino-N-(2-(4-methoxyphenyl)-4-oxothiazolidin-3-yl)-1,4-dihydro quinoxaline-2-carboxamide (IX) and 2-(3-amino-1,4-dihydroquinoxaline-2-carbonyl)-N-phenyl hydrazine carbothioamide (XI) exerted the highest antifungal activities against Aspergillus flavus and Candida albicans fungi.
Keywords: pyrazole, quinoxaline, carbohydrazide, thiadiazoles, antibacterial, antifungal _________________________ Полный текст статьи печатается в переводной версии журнала Russian Journal of Bioorganic Chemistry, V.46, Issue 5, P. 715-725 (Springer).