Oxidative Dehydrogenative Couplings of Pyrazol-5-amines Selectively Forming Azopyrroles

New oxidative dehydrogenative couplings of pyrazol-5-amines for the selective synthesis of azopyrrole derivatives have been described. The former reaction simultaneously installs C–I and N–N bonds through iodination and oxidation, whereas the latter involved a copper-catalyzed oxidative coupling process. The resulting iodo-substituted azopyrroles were employed by treatment with various terminal alkynes through Sonogashira cross-coupling leading to new azo compounds.本研究报道了一类用于选择性合成偶氮吡咯衍生物（azopyrrole derivatives）的5-氨基吡唑（pyrazol-5-amines）新型氧化脱氢偶联反应。其中一类反应通过碘化与氧化过程，同时构建碳碘（C–I）键与氮氮（N–N）键；而另一类反应则为铜催化的氧化偶联过程。所得碘取代偶氮吡咯可与各类末端炔烃经薗头交叉偶联（Sonogashira cross-coupling）反应制备新型偶氮化合物。