2.5- Difluoro-3-methoxypyrazine

Tetrafluoropyrazine with hydrazine gives 2,3,5-trifluoro-6-hydrazinopyrazine which on warming with aqueous copper sulfate gave trifluoropyrazine and 2,3-difluoro-5-hydrazino-6-methoxypyrazine similarly treated gave 2,3-difluoro-5-methoxypyrazine (885), but 2,3,5-trichloropyrazine could not be prepared from... 

Chloro-3,6-difluoro-5-hydrazinopyrazine 2-Chloro-3,6-difluoro-5-methoxypyrazine 2-Chloro-3,6-diisobutyl-5-methoxypyrazine 2-Chloro-3,6-diisobutylpyrazine 2-Chloro-3,6-diisobutylpyrazine 1, 4-dioxide... 

Treatment of tetrafluoropyrazine in concentrated sulfuric acid with methanol at 20° has been shown to give 2,3,5-trifluoro-6-methoxypyrazine, and similar treatment of the latter gave 2,3-difluoro-5,6-dimethoxypyrazine (851). 

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