- Synthesis of Mutagenic Methyl- and Phenyl-substituted 2-Amino-3H-imidazoquinoxalines via 2,1,3-Benzoselenadiazoles
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2-Amino-3-methyl-3H-imidazoquinoxaline, all its derivatives with 1-4 methyl groups in positions 4, 5, 7 and 8, and 2-amino-3,5-dimethyl-7,8-diphenyl-3H-imidazoquinoxaline have been synthesized from the corresponding 6-methylamino-5-nitroquinoxalines through reduction and cyclization with cyanogen bromide.The quinoxalines were obtained from the appropriate α-dicarbonyl compounds and 4-methylamino-3-nitro-1,2-benzenediamines.The latter were prepared from 4-halo-1,2-benzenediamines via 2,1,3-benzoselenadiazoles.The 7- and 8-phenyl derivatives of 2-amino-3,5-dimethyl-3H-imidazoquinoxaline have been synthesized in a slightly different way.
- Grivas, Spiros,Tian, Wei,Ronne, Erik,Lindstroem, Stefan,Olsson, Kjell
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p. 521 - 528
(2007/10/02)
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- Regiospecific Synthesis of the Aminoimidazoquinoxaline (IQx) Mutagens from Cooked Foods
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A versatile regiospecific synthesis has been developed to prepare the six dimethyl- and trimethyl-substituted 2-aminoimidazoquinoxaline (IQx) regioisomers 35, 36, 37, 38, 39, and 40 for complete and unambiguous characterization.The key reaction step in the synthetic sequence for these angular tricycles is a photodehydrohalogenative cyclization of suitably substituted pyrazinylimidazolylethylene intermediates derived from common pyrazine and fully functionalized imidazole precursors.The reaction sequence developed allows for versatility in the substitution pattern as well as total regioisomeric control for the synthesis of all possible methyl and polymethyl analogues of IQx.Comparison of the physical properties among the isomeric di- and trimethyl-IQx's has established the value of unambiguous regiospecific synthesis for structural assignments in this food mutagen series.
- Bierer, Donald E.,O'Connell, John F.,Parquette, Jon R.,Thompson, Charles M.,Rapoport, Henry
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p. 1390 - 1405
(2007/10/02)
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- An improved synthesis of 3,8-dimethyl-3H-imidazo[4,5-f]quinoxalin-2-amine ("MeIQx") and its 2-14C-labelled analogue.
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The highly mutagenic title compound (MeIQx) was prepared in 21% overall yield from 4-fluoro-o-phenylenediamine. The 3,7-dimethyl isomer may be obtained as a minor by-product. The 14C-label was introduced in the last step through cyclization with [14C]cyanogen bromide. An alternative synthesis of MeIQx from p-fluoroaniline avoided the separation of isomers but gave poorer yield.
- Grivas,Olsson
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- SYNTHESIS OF 2-AMINO-3,8-DIMETHYLIMIDAZOQUINOXALINE (Me-IQx), A POTENT MUTAGEN ISOLATED FROM FRIED BEEF
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A potent mutagen, 2-amino-3,8-dimethylimidazoquinoxaline (Me-IQx), isolated from fried beef and its 3,7-dimethyl derivative were synthesized from 6-amino-3-methylquinoxaline and 6-amino-2-methylquinoxaline, respectively.These compounds showed strong mutagenic activity towards Salmonella typhimurium TA98 in the presence of S9 Mix.
- Kasai, Hiroshi,Shiomi, Tomoko,Sugimura, Takashi,Nishimura, Susumi
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p. 675 - 678
(2007/10/02)
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