Some reactions of mono substituted pyrazine monoxides

The reactions of the monoxides of propylpyrazine and phenylpyrazine with phosphoryl chloride or acetic anhydride were investigated. Except in the case of the reaction of 2-propylpyrazine 1-oxide with acetic anhydride, chlorination or acetoxylation occurred on the pyrazine ring in all cases; moreover, these reactions occurred preferentially at the position poorest in π-electron density. The N-oxidation and the successive chlorination of monochloro-phenylpyrazines were also investigated, and the structures of the products were confirmed.