A simple, new and convenient metal free procedure for the synthesis of 5-substituted 1H-tetrazoles using various nitriles and sodium azide in the presence of urea and acetic acid with good to high yields is developed. The reaction plausibly proceeds through in situ formation of urea azide active complex without toxic and/or expensive metal catalysts.

中文翻译：

---

尿素通过腈和叠氮化钠的[3 + 2]环加成反应介导的5-取代-1H-四唑

开发了一种简单，新颖，方便的无金属合成方法，该方法利用各种腈和叠氮化钠在尿素和乙酸的存在下以良好或高收率合成5-取代的1 H-四唑。该反应似乎是通过在没有毒性和/或昂贵的金属催化剂的情况下原位形成叠氮化脲活性配合物而进行的。