Organic Chemistry Portal

Abstracts

Search:

Copper-Catalyzed Aerobic Oxidative Cyclization of 2-Alkynylanilines with Nitrosoarenes: Synthesis of Organic Solid Mechanoluminescence Compounds of 4-Oxo-4H-cinnolin-2-ium-1-ide

Xiaolan Fang, Ji Cao, Weijie Ding, Huile Jin, Xiaochun Yu* and Shun Wang*

*College of Chemistry & Materials Engineering, Wenzhou University, Wenzhou, 325035, P. R. China, Email: xiaochunyuwzu.edu.cn, shunwangwzu.edu.cn

X. Fang, J. Cao, W. Ding, H. Jin, X. Yu, S. Wang, Org. Lett., 2021, 23, 1228-1233.

DOI: 10.1021/acs.orglett.0c04186


Abstract

An efficient Cu(I)/DMAP/air system enables a one-pot synthesis of 4-oxo-4H-cinnolin-2-ium-1-ides from substituted 2-alkynylanilines and nitrosoarenes. The use of an inexpensive copper catalyst and molecular oxygen as the oxygen source and the oxidant make this an attractive green protocol.

see article for more examples


proposed mechanism



Details

The document discusses the development of an efficient Cu(I)/DMAP/air system for the one-pot synthesis of 4-oxo-4H-cinnolin-2-ium-1-ides from substituted 2-alkynylanilines and nitrosoarenes. These compounds have practical applications as mechanoluminescent materials. The use of an inexpensive copper catalyst and molecular oxygen as the oxidant makes this a green protocol with potential synthetic applications. The study optimized reaction conditions, finding that CuCl and DMAP in toluene at 100°C under air for 24 hours provided the best yields. The reaction scope was tested with various functional groups, showing good yields for aryl, heteroaryl, and alkyl derivatives, but not for alkenyl derivatives. Mechanistic studies suggested that the reaction involves the formation of an azobenzene intermediate, which undergoes intramolecular cyclization and oxidation. The resulting 4-oxo-4H-cinnolin-2-ium-1-ides exhibit mechanoluminescence, changing fluorescence under mechanical stress. This method offers a convenient and practical approach to synthesizing these compounds, with ongoing studies to explore further synthetic applications. The research was supported by the National Natural Science Foundation of China and the Natural Science Foundation of Zhejiang Province.


Key Words

benzo-fused N-heterocycles, oxygen


ID: J54-Y2021