Facile Synthesis of 2-Substituted Aminobenzoxazole. One Pot Cyclodesulfurization ofN-(2-Hydroxyphenyl)-N′-phenylthioureas with Superoxide Radical Anion
Iodide catalyzed synthesis of 2-aminobenzoxazoles via oxidative cyclodesulfurization of phenolic thioureas with hydrogen peroxide
作者:Vinod K. Yadav、Vishnu P. Srivastava、Lal Dhar S. Yadav
DOI:10.1016/j.tetlet.2017.12.019
日期:2018.1
A convenient and efficient oxidative cyclodesulfurization of o-phenolic thioureas to 2-aminobenzoxazoles employing TBAI (tetrabutylammonium iodide)/H2O2 catalyst/reagent system is reported. The protocol utilizes and offers a number of desired features such as metal-free, base-free, simple operation, room temperature, low cost catalyst/reagent, no need for anhydrous and inert conditions. The approach
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。
One-pot reaction for the synthesis of N -substituted 2-aminobenzoxazoles using triphenylbismuth dichloride as cyclodesulfurization reagent
dichloride promoted the successful cyclodesulfurization of thioureas with short reaction times under mild reaction conditions. This reaction is the first example of the synthesis of heterocyclic rings using a pentavalent organobismuth reagent.
5-Lipoxygenase (5-LOX) is important enzyme in the biosynthesis of leukotrienes, and is a potential target in the treatment of asthma and allergy. We designed and synthesized a series of benzoxazoles and benzothiazoles as 5-LOX inhibitors. Fourteen compounds prepared showed the inhibition of LTC4 formation with IC50 value of 0.12-23.88 mu M. Also two compounds 2d and 2g showed improved airway hypersensitiveness. (C) 2010 Elsevier Ltd. All rights reserved.
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.