| 摘要 |
A process for the preparation of 2-carboxpyrazine 4-oxides having the formula (I) <IMAGE> (I) wherein R1, R2 and R3, which may be the same or different, represent a hydrogen atom or an alkyl group having from 1 to 6 carbon atoms, by oxidation of the corresponding 2-carboxypyrazines. The 2-carboxypyrazines are reacted under stirring with an aqueous solution of H2O2, at a pH ranging between 0.5 and 5, in the presence of a catalyst selected from the group consisting of tungstic acid, a isopolytungstic acid, a heteropolytungstic acid, molybdic acid, an isopolymolybidic acid, a heteropolymolybdic acid, and an alkali metal salt thereof. |
