- Bromination of quinoxaline and derivatives: Effective synthesis of some new brominated quinoxalines
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The synthesis of brominated quinoxaline derivatives starting from several kinds of quinoxaline by different bromination strategies was studied. First the synthesis of some brominated quinoxalines was accomplished along with the development of an alternative and effective synthesis of some known compounds. A new, clean, and effective synthetic method for selective reduction of quinoxaline to 1,2,3,4-tetrahydroquinoxaline was also developed. The products obtained were characterized by means of NMR spectroscopy, elemental analyses, and mass spectrometry.
- U?ar, Sefa,E?siz, Sel?uk,Da?tan, Arif
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p. 1618 - 1632
(2017/03/08)
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- Redox-activated, hypoxia-selective DNA cleavage by quinoxaline 1,4-di-N-oxide
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Quinoxaline 1,4-dioxide (4) is the historical prototype for modern heterocyclic N-oxide antitumor agen s such as 3-amino-1,2,4-benzotriazine 1,4-dioxide (tirapazamine, 1) and 3-amino-2-quinoxalinecarbonitrile 1,4-dioxide (11). Early experiments in bacterial cell lines suggested that enzymatic, single-electron reduction of quinoxaline 1,4-dioxides under low-oxygen (hypoxic) conditions leads to DNA damage. Here the ability of quinoxaline 1,4-dioxide to cleave DNA has been explicitly characerized using in vitro assays. The hypoxia-selective DNA-cleaving properties of 4 reported here may provide a chemical basis for understanding the cytotoxic and mutagenic activities of various quinoxaline 1,4-dioxide antibiotics. Copyright
- Ganley, Brian,Chowdhury, Goutam,Bhansali, Jennifer,Daniels,Gates, Kent S.
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p. 2395 - 2401
(2007/10/03)
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- PARTIAL REDUCTION OF QUINOXALINE 1,4-DIOXIDE DERIVATIVES WITH L-ASCORBIC ACID
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Partial reduction of quinoxaline 1,4-dioxide derivatives with L-ascorbic acid has been elaborated.Quinoxaline 1,4-dioxide, 2,3-dimethylquinoxaline 1,4-dioxide, 2-methylquinoxaline 1,4-dioxide and 2-(N-(2-hydroxyethyl)carbamoyl)-3-methylquinoxaline 1,4-dioxide afforded monoxides.In the monomethyl derivatives the more distant N-O bond is reduced.In addition to the monoxide, quinoxaline 1,4-dioxide afforded small amount of quinoxaline.Structures of all the compounds have been confirmed by 1H and 13C NMR spectroscopy.
- Novacek, Libor,Nechvatal, Miloslav
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p. 1302 - 1306
(2007/10/02)
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