报道了使用TBAI(碘化四丁铵)/ H 2 O 2催化剂/试剂系统将邻苯酚硫脲方便且有效地氧化成2-氨基苯并恶唑的氧化环脱硫。该方案利用并提供了许多所需的功能,例如无金属,无碱,操作简单,室温,低成本的催化剂/试剂,不需要无水和惰性条件。该方法还适用于直接从邻氨基苯酚和异硫氰酸芳基酯开始的一锅合成2-氨基苯并恶唑,产率高。
An economically and environmentally sustainable synthesis of 2-aminobenzothiazoles and 2-aminobenzoxazoles promoted by water
作者:Xinying Zhang、Xuefei Jia、Jianji Wang、Xuesen Fan
DOI:10.1039/c0gc00418a
日期:——
Tandemreactions of isothiocyanates (1) with 2-aminothiophenols (2), or isothiocyanates (1) with 2-aminophenols (4), were carried out rapidly and efficiently in water. A significant rate acceleration of the reaction between 1a and 2a in water compared with commonly used volatile organic solvents was observed. Through these reactions, a variety of structurally and pharmaceutically interesting 2-aminobenzothiazoles
Visible-light-promoted cyclodesulfurization of phenolic thioureas: an organophotoredox catalytic approach to 2-aminobenzoxazoles
作者:Vinod K. Yadav、Vishnu P. Srivastava、Lal Dhar S. Yadav
DOI:10.1016/j.tetlet.2015.11.089
日期:2016.1
A facile and efficient one-pot operation for the photo-oxidative cyclodesulfurization of o-phenolic thioureas to afford 2-aminobenzoxazoles is reported. The protocol could be executed under visible light irradiation employing eosin Y as an organophotoredox catalyst and offers a superior alternative to the existing methods of the cyclodesulfurization of phenolic thioureas. The salient features of the present metal-free approach are the utilization of air and visible light as the greenest and sustainable reagents under mild conditions. (C) 2015 Elsevier Ltd. All rights reserved.