Syntheses of some 2-hydroxypyrazine 1-oxides

A series of 2-hydroxypyrazine 1-oxides were prepared from the corresponding chloropyrazines by two methods, including oxidation processes in satisfactory yields. The treatment of 2,3-diphenylpyrazine 1,4-dioxide (6) led to 2,3-dichloro-5,6-diphenylpyrazine (7) and 2-chloro-5,6-diphenylpyrazine 1-oxide (8), and the latter was converted to 5,6-diphenyl-2-hydroxypyrazine 1-oxide (9) by an alkaline hydrolysis.