By Interconversion of Alkyl or Aryl Substituents

This subsection covers not only the conversion of one simple alkylquinoxaline into another but also the conversion of a (functionally substituted alkyl)quinoxaline into another such quinoxaline provided the alkyl portion, and not just the functionality, is changed. The following classihed examples illustrate typical processes involved. 

2-Methylquinoxaline 1,4-dioxide gave 2-styrylquinoxaline 1,4-dioxide (81) (PhCHO, KOH, MeOH, 18°C, 12 h 65%).  

3-Ethoxycarbonyhnethyl-2(17/)-quinoxalinone gave 3-(p-dimethylamino-a-ethoxy-carbonylstyryl)-2(17/)-quinoxalinone (84) (OHCC6H4NMe2-p, AcOH, ACONH4, reflux, 2h 15%) 

2-Methylquinoxaline gave 2-(2-dimethylaminovinyl)quinoxaline (85) [Bu OCH-(NMe2)2, Me2NCHO, reflux, 15 min 98%].  

3-Dimethyl-2(l//)-quinoxalinethione gave 3-(2-dimethylamino-1 -formylvinyl)-1 -methyl-2(l//)-quinoxalinethione (86) Me2NCHO, POCI3, 0°C 20 min then substrate, 60°C, 5h 78% note the additional C-formylation).  

3-Di methyl-2( 1 //)-quinoxalinone gave l-methyl-3-styryl-2(l//)-quinoxalinone (82) [neat PhCHO, trace HN(CH2)5, A until molten, 10 min 85% several o- or p-substituted analogs likewise].105 

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Quinoxaline, Alkylquinoxalines, and Arylquinoxalines 2.2.1.4. By Interconversion of Alkyl or Aryl Substituents... 

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