2.3.6.7- Tetrachloro-5-methylquinoxaline

Methylquinoxaline is reported to give a polycyclic derivative (117) related to quinoxaline orange with 2-equivalents of tetrachloro-1,2-ben zoquinone 2-(2-quinoxalino)-4,5,6,7-tetrachlorobenzo-1,3-dioxole... 

Methylquinoxaline also undergoes a novel cycloaddition reaction with two equivalents of tetrachloro-l,2-benzoquinone129 (see Section III,A) with formation of a quinoxaline-orange type product. The reaction probably proceeds by initial formation of the quaternary salt 231 which by elimination of HC1, followed by protonation and dehydration, leads to the cyclized product 232. This on reaction with a further equivalent of tetrachloro-l,2-benzoquinone at the C=N function gives the final yellow compound 117. 

An interesting special case is the reaction of 2-methylquinoxaline (212) with tetrachloro-o-benzoquinone (Scheme 49), which gives the hexacyclic product (214), presumably via the intermediate salt (213) (70CJC327). 

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