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Synthesis and Antibacterial Activity of Fused 1, 2, 4‐Triazolo[4, 3‐ a ]quinoxaline and Oxopyrimido[2′, 1′:5, 1]‐1, 2, 4‐triazolo[4, 3‐ a ]quinoxaline Derivatives
Author(s) -
Nasr Magda Nasr Ahmed
Publication year - 2002
Publication title -
archiv der pharmazie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.468
H-Index - 61
eISSN - 1521-4184
pISSN - 0365-6233
DOI - 10.1002/1521-4184(200211)335:8<389::aid-ardp389>3.0.co;2-x
Subject(s) - quinoxaline , chemistry , phenyl isothiocyanate , antibacterial activity , isothiocyanate , chalcone , potassium hydroxide , diethyl malonate , medicinal chemistry , vanillin , triethylamine , malononitrile , organic chemistry , stereochemistry , biology , bacteria , genetics , catalysis
A new series of potential antibacterial agents having tricyclic 1, 2, 4‐triazolo‐[4, 3‐ a ] quinoxaline fused with one or more heterocyclic rings was synthesized via several routes. The tricyclic 1‐amino‐4‐chloro‐1, 2, 4‐triazolo[4, 3‐ a ] quinoxaline ( 2 ) and tetracyclic 1, 6‐diamino‐bis‐1, 2, 4‐triazolo[4, 3‐ a :3, 4‐ c ] quinoxaline ( 3 ) were synthesized from 2, 3‐dichloroquinoxaline ( 1 ) with two or four equivalents of thiosemicarbazide, respectively. Compound 2 was allowed to react with different aldehydes, alkoxides, cyclic amines, phenyl isothiocyanate, and t ‐butyl isocyanate to afford the corresponding quinoxaline derivatives. Moreover, compound 2 reactedwithhydrazine hydrate to give compound 4 which was cyclized by carbondisulfide inalcoholic potassium hydroxide to give the tetracyclic compound 5 . Compound 2 was subjected to another cyclocondensation reaction using diethyl ethoxymethylene malonate (DEMM), dimethyl acetylenedicarboxylate (DMAD), and ethyl cyanoacetate to give the tetracyclic compounds 18 , 20 , and 21 , respectively. All the synthesized compounds were evaluated in vitro for antibacterial activity; compounds 18 and 20 were found to display the greatest antibacterial activities. Structural identification was provided by elemental analyses, IR, and 1 H‐NMR spectroscopy.