2,3-Dimethylquinoxaline 1,4-dioxide preparation

Dimethylquinoxaline from its 1,4-dioxide (258) (Mg, NH4OAC, MeOH, reflux >32% for more detail and analogous preparations, see original).302... 

A poly(phenylquinoxaline) was prepared for electroluminescence applications <1996SM(76)105>. Crystallization of solution donor-acceptor complexes of 2,3-dimethylquinoxaline 1,4-dioxide or phenazine 5,10-dioxide with TCNE afforded two-component solids containing weakly bound 1-D donor-acceptor arrays <1997TL7665>. A pyrazine ladder polymer was constructed from two different pyrazine units, as an optical device <1999JA8783>. The new electron-deficient macrocycle tetrakis-2,3-[5,6-di(2-pyridyl)pyrazino]porphyrazine was prepared from l,2-di(2-pyridyl)ethanedione and 2,3-diaminomaleonitrile for a study of its electrochemical properties <2004IC8626>. 

Fig. 5 Preparation of 2,3-dimethylquinoxaline 1,4-dioxide from o-quinone dioxime...

Dimethylquinoxaline can be oxidized with peracetic acid in acetic acid to a mono- or di-N-oxide by appropriate choice of reaction conditions. 1,4-Dioxides have also been prepared with this reagent from other 2,3-dialkylquinoxalines, but similar treatment of 2-isopropyl-... 

Selenium dioxide oxidation of 2-methylquinoxaline yields quinoxaline-2-carboxaldehyde, and 3-methylquinoxaline-2-carboxaldehyde has been similarly prepared from 2,3-dimethylquinoxaline. Dimethylsulfoxide oxidation of 2,3-bis(bromomethyl)quinoxaline yields the furoquinoxaline 45, and this on sublimation gives quinoxaline-2,3-dicarboxaldehyde. 3-Dibromomethylquinoxaline-2-carboxaldehyde (46) is a by-product of the oxidation reaction. Direct selenium dioxide oxidation of 2,3-dimethylquinoxaline appears to be a less satisfactory method of preparing the dialdehyde. ... 

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