Department of Chemistry, Institute of Science, Banaras Hindu University, Varanasi 221005, India.
Chemical Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa 403004, India.
J Org Chem. 2021 Dec 17;86(24):18004-18016. doi: 10.1021/acs.joc.1c02275. Epub 2021 Nov 24.
We have developed an electrochemical approach for the synthesis of fully substituted 1,2,3-thiadiazoles from α-phenylhydrazones at room temperature, which is very challenging and complementary to the conventional thermal reactions. The key step involves anodic oxidation of phenylhydrazone derivatives at a constant current followed by N,S-heterocyclization. The protocol is remarkable in that it is free of a base and free of an external oxidant and can be converted to a gram scale for postsynthetic drug development with functional thiadiazoles. Most importantly, the electrochemical transformation reflected efficient electro-oxidation with an operationally friendly easy procedure with ample functional molecules. Cyclic voltammograms support the mechanism of this electro-oxidative cyclization process.
我们开发了一种电化学方法，可在室温下从α-苯腙合成完全取代的 1,2,3-噻二唑，这与传统的热反应非常具有挑战性和互补性。关键步骤包括在恒定电流下对苯腙衍生物进行阳极氧化，然后进行 N,S-杂环化。该方案的显著特点是无需碱和外部氧化剂，并且可以转化为克级规模，用于具有功能噻二唑的后期合成药物开发。最重要的是，电化学转化反映了高效的电氧化，操作简便，具有丰富的功能分子。循环伏安法支持这种电氧化环化过程的机理。
