A practical method through sunlight mediated annulation of α,β‐unsaturated hydrazones has been developed for the synthesis of pyrazole. Based on the analysis of UV‐Vis absorption of the substrate, the reaction was designed to avoid the use of external photocatalysis and proceeds via direct irradiation of N‐centred anion by sunlight. The key features of this reaction include operational simplicity, readily available reagents, and amenability to gram‐scale synthesis.

中文翻译：

---

阳光促进的N中心阴离子的直接辐照：水中无吡咯类的光催化剂合成

已经开发了一种通过日光介导的α，β-不饱和azo的环合反应的实用方法，用于合成吡唑。基于对底物的UV-Vis吸收的分析，该反应被设计为避免使用外部光催化，并通过阳光直接照射N中心阴离子进行反应。该反应的关键特征包括操作简便，易于获得的试剂以及对克级合成的适应性。