2.3.5- Trifluoro-6-hydrazinopyrazine

Trifluoropyrazine has been prepared from tetrafluoropyrazine through 2,3,5-trifluoro-6-hydrazinopyrazine by removal of the hydrazino substituent with aqueous copper sulfate (885). Fluorination of tetrafluoropyrazine in nitrogen in the presence of cobalt(lll) fluoride and calcium fluoride at 80° gave perfluoro-1,4-diazocyclohexa-13-diene (IS) (886). 

Tetrafluoropyrazine has been converted to 2,3,5-trifluoro-6-hydrazinopyrazine and thence to 2-chloro- and 2-bromo-3,5,6-trifluoropyTazine by reaction with ferric chloride in concentrated hydrochloric acid and cupric bromide in aqueous... 

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... 

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