Approach for 2-(arylthio)imidazoles and imidazo[2,1-b]thiazoles from imidazo[2,1-b][1,3,4]thiadiazoles by ring-opening and -reconstruction

• Published in: Organic & biomolecular chemistry Vol. 14; no. 10; pp. 2978 - 2984
• Main Authors: Shi, Benyi, Zhu, Zhouhe, Zhu, Yi-Shuo, Zhou, Dagang, Wang, Jinyuan, Zhou, Panpan, Jing, Huanwang
• Format: Journal Article
• Language: English
• Published: CAMBRIDGE Royal Soc Chemistry 01.01.2016
• Subjects: Chemistry; Chemistry, Organic; Physical Sciences; Science & Technology; ASYMMETRIC CATALYSIS; LISSOCLINUM CF. BADIUM; HETEROCYCLES; SULFIDES; BOND FORMATION; SULFUR; AGENTS; LIGAND; ORGANIC SEMICONDUCTORS; DERIVATIVES
• ISSN: 1477-0520; 1477-0539
• DOI: 10.1039/c6ob00102e

A highly efficient one-pot synthesis of imidazo[2,1-b]thiazole derivatives has been developed and proceeds via a ring-opening and ring-closing reconstruction of imidazo[2,1-b][1,3,4]thiadiazoles with phenylacetylene in the presence of potassium tert-butoxide (t-BuOK) under very mild reaction conditions. A proposed mechanism is calculated computationally using a DFT method at the B3LYP/6-31+G(d, p) level. The imidazo[2,1-b][1,3,4]thiadiazoles are also successfully converted to a series of 2-(arylthio)-1H-imid-azoles using aryl halide as a reactant and copper(II) acetylacetonate (Cu(acac)(2)) as a catalyst under microwave irradiation conditions. The key features of these reactions are the use of readily available reagents, simple operation, the convenient utilization of new heterocyclic synthons, and a great variety of substrates with functional group compatibility.