2-Hydroxy-5-nitro-3-phenylpyrazine

Hydroxy-3-phenylpyrazine nitrate (prepared from 2-hydroxy-3-phenylpyrazine and one equivalent of nitric acid in acetic acid) boiled in acetic acid gave 2-hydroxy-5-nitro-3-phenylpyrazine. It was postulated that, in hot acetic acid, dissociation of the nitrate was a relatively slow and temperature-dependent process which was followed by very rapid nitration of the nucleus (817). 

Hydroxy-5-nitro-3-phenylpyrazine with phosphoryl chloride at reflux gave 2-chloro-5-nitro-3-phenylpyrazine but at 170° gave 2,5-dichloro-3-phenylpyrazine (817). Phenylhydroxynitropyrazines are claimed not to react with dimethyl sulfate in alkaline solution or with sodium ethoxide and ethyl iodide in hot ethanol (817). 

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See also in sourсe #XX -- [ ]

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