A Metal-Free Amination of Benzoxazoles – The First Example of an Iodide-Catalyzed Oxidative Amination of Heteroarenes
作者:Tanja Froehr、Christian P. Sindlinger、Ulrich Kloeckner、Peter Finkbeiner、Boris J. Nachtsheim
DOI:10.1021/ol201439t
日期:2011.7.15
An efficient transition-metal-free amination of benzoxazoles has been developed. With catalytic amounts of tetrabutylammoniumiodide (TBAI), aqueous solutions of H2O2 or TBHP as co-oxidant and undermild reaction conditions, highly desirable 2-aminobenzoxazoles were isolated in excellent yields of up to 93%. First mechanistic experiments indicate the in situ iodination of the secondary amine as the
已经开发出有效的无过渡金属苯并恶唑胺化的方法。用催化量的四丁基碘化铵(TBAI),H 2 O 2或TBHP水溶液作为助氧化剂,并在温和的反应条件下,以高达93%的优异收率分离出了非常理想的2-氨基苯并恶唑。最初的机械实验表明,仲胺的原位碘化是假定的活化方式。
Metal-free synthesis of 2-aminobenzoxazoles using hypervalent iodine reagent
作者:Yogesh S. Wagh、Neelam J. Tiwari、Bhalchandra M. Bhanage
DOI:10.1016/j.tetlet.2012.12.127
日期:2013.3
A facile, simple, mild, and metal-free protocol for the synthesis of 2-aminobenzoxazoles has been developed via C–H bond amination of benzoxazoles with amines through a ring-opening and subsequent ring-closure approach. The reaction was performed in two steps wherein nucleophilic addition of amines across benzoxazoles takes place in the absence of any reagent or catalyst under solvent-free condition
Metal-free N-iodosuccinimide-catalyzed mild oxidative C–H bond amination of benzoxazoles
作者:Yogesh S. Wagh、Dinesh N. Sawant、Bhalchandra M. Bhanage
DOI:10.1016/j.tetlet.2012.04.117
日期:2012.7
facile, efficient, and mild protocol for the synthesis of aminobenzoxazoles has been developed using direct oxidative C–H bond amination of benzoxazoles with secondary or primary amines. The reaction was performed using catalytic amount of N-iodosuccinimide and aqueous hydrogen peroxide as a green oxidant and in the absence of transition metals. Reaction proceeds smoothly at ambient temperature and
The Synthesis of 2-Aminobenzoxazoles Using Reusable Ionic Liquid as a Green Catalyst under Mild Conditions
作者:Ya Zhou、Zhiqing Liu、Tingting Yuan、Jianbin Huang、Chenjiang Liu
DOI:10.3390/molecules22040576
日期:——
A facile, green, and efficient method for the direct oxidative amination of benzoxazoles using heterocyclic ionic liquid as catalyst has been developed. The reaction proceeded smoothly at room temperature and gave the desirable 2-aminobenzoxazoles with good to excellent yields (up to 97%). The catalyst 1-butylpyridinium iodide can be easily recycled and reused with similar efficacies for at least four cycles.
A green approach for the synthesis of 2-amino azoles by the reaction of 2-chloro azoles with various types of amines using water as an environment friendly solvent at room temperature has been developed. The significant features of this methodology are short reaction time and easy product separation. This approach provides various biologically active compounds in good to excellent yields without adding any catalyst, ligand, or base. (C) 2015 Elsevier Ltd. All rights reserved.