Preparation of N-Alkylpyrazinium Salts

The quatemization of pyrazines has been done under a wide variety of conditions, as illustrated in Section 3.1.3 and in the following recent examples  

Dimethyl 2,3-pyrazinedicarboxylate gave l-ethyl-2,3-dimethoxycarbonylpyrazinium tetrafluoroborate (347) (Et3OBF4, C1CH2CH2C1, reflux, 2 h 80%) 415 methyl 2-pyrazinecarboxylate gave 3-methoxycarhonyl-l -methylpyrazininm iodide (348) 

2-Methylpyrazine 1-oxide gave 1,3-dimethylpyrazinium iodide 4-oxide (351) 

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