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VOL. 9, ISSUE 2 (2025)
Synthesis and characterization of 2, 9-(disubstituted)-6,13-dimethoxy 5,12-dihydroquinoxalino[2,3-b] phenazine derivatives
Authors
Ch. Sudhakar
Abstract
Phenazine and quinoxaline
derivatives represent crucial nitrogen containing heterocyclic architectures
with a remarkably broad spectrum of pharmaceutical, agricultural, and
technological applications. In this study, we have reported the design,
synthesis, and comprehensive spectral characterization of a novel series of
2,9-(disubstituted)-6,13-dimethoxy-5,12-dihydroquinoxalino (2,3-b) phenazine
derivatives (6a–d). The synthetic methodology utilizes
2,5-dibromo-3,6-dimethoxy-1,4-benzoquinone as a core scaffolding precursor,
which undergoes condensation when reacted with one molar equivalents of various
substituted ortho-phenylenediamines. This reaction was efficiently executed
under reflux conditions in an ethanolic medium containing anhydrous sodium
acetate as a mild basic catalyst, delivering the desired ladder type
pentacyclic framework in moderate to high yields ranging from 52% to 61%. All
synthesized nitrogenous heterocycles were isolated as distinct crystalline
solids and rigorously purified via silica gel column chromatography. The
molecular structures of the target fluorindine analogues were unambiguously
verified through a combination of spectroscopic analytical techniques,
including Fourier-transform infrared spectroscopy (FT-IR), proton nuclear
magnetic resonance (1H NMR), carbon-13 nuclear magnetic resonance (13C
NMR), and electrospray ionization mass spectrometry (ESI-MS), as well as
elemental analysis. The spectral data consistently confirmed the complete
disappearance of the parent phinazinone carbonyl absorption. The structural
versatility, stability, and streamlined synthesis of these novel
5,12-dihydroquinoxalino(2,3-b) phenazine systems position them as highly
promising candidates for future investigation as active pharmaceutical agents,
agricultural biocides, or building blocks for organic field-effect transistors
and optoelectronic semiconductor materials.
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Pages:94-96
How to cite this article:
Ch. Sudhakar "Synthesis and characterization of 2, 9-(disubstituted)-6,13-dimethoxy 5,12-dihydroquinoxalino[2,3-<i>b</i>] phenazine derivatives". International Journal of Chemical Science, Vol 9, Issue 2, 2025, Pages 94-96
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