In-situ-generated N-aryl nitrile imines derived from trifluoroacetonitrile efficiently react with polycyclic 1,4-quinones, yielding fused pyrazole derivatives as the exclusive products. The reactions proceed via the initially formed [3 + 2]-cycloadducts, which undergo spontaneous aerial oxidation to give aromatized heterocyclic products. Only for 2,3,5,6-tetramethyl-1,4-benzoquinone, the expected [3 + 2]-cycloadduct exhibited fair stability and could be isolated in moderate yield (53%). The presented method offers a straightforward access to hitherto little known trifluoromethylated polycyclic pyrazoles. All products were isolated as pale colored solids with medium-intensity absorption maxima in the range of 310–340 nm for naphthoquinone-derived products and low-intensity bands in the visible region (≈400 nm) for the anthraquinone series.

中文翻译：

---

通过[3 + 2]-环加成与氟化腈亚胺直接将1,4-醌转化为多环吡唑

原位生成的氮衍生自三氟乙腈的芳基腈亚胺与多环 1,4-醌有效反应，生成稠合吡唑衍生物作为独家产物。反应通过最初形成的 [3 + 2]-环加合物进行，这些环加合物进行自发的空气氧化，得到芳构化的杂环产物。仅对于 2,3,5,6-四甲基-1,4-苯醌，预期的 [3 + 2]-环加合物表现出相当的稳定性，并且可以以中等产率 (53%) 分离。所提出的方法提供了对迄今为止鲜为人知的三氟甲基化多环吡唑的直接访问。所有产品均被分离为浅色固体，萘醌衍生产品的中等强度吸收最大值在 310-340 nm 范围内，蒽醌系列产品在可见光区（≈400 nm）具有低强度带。