Direct access to alkyl‐substituted pyrazine N‐oxides has been accomplished through an intermolecular dehydrogenative cross‐coupling reaction of ethers and pyrazine N‐oxides in the presence of tert‐butyl hydroperoxide (TBHP). This approach successfully provided a variety of alkyl‐substituted pyrazine N‐oxides in up to 96 % yield. Thermogravimetric analysis indicates that the degradation temperature of C2‐alkyated product 3 a is approximately 263 °C. Under pyrolysis conditions, 3 a generated several compounds such as 2,5‐dimethylpyrazine, 2,3,5‐trimethylpyrazine, and 3‐ethyl‐2,5‐dimethylpyrazine, which are characterized by their distinct aromas. The results of the pyrolysis experiment support the use of these compounds as possible flavor additives.

中文翻译：

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不含过渡金属的氧化交叉偶联反应合成烷基取代的吡嗪N-氧化物

在叔丁基氢过氧化物（TBHP）存在下，醚和吡嗪N-氧化物的分子间脱氢交叉偶联反应可直接获得烷基取代的吡嗪N-氧化物。这种方法成功地提供了多种烷基取代的吡嗪N-氧化物，收率高达96％。热重分析表明，C2烷基化产物3a的降解温度约为263°C。在热解条件下，3 a生成了2,5-二甲基吡嗪，2,3,5-三甲基吡嗪和3-乙基-2,5-二甲基吡嗪等几种化合物，它们具有独特的香气。热解实验的结果支持使用这些化合物作为可能的风味添加剂。