Cetyltrimethylamonium hydrogensulfate catalyzed synthesis of quinoxalines in aqueous media at room temperature

The aim of this study is to provide quinoxaline derivatives as useful compounds in pharmaceutical chemistry that have a wide range of biological activities such as antiviral, antibacterial, anti-inflammatory, anti-tumor, and depression, as well as efficacy in the industry[1]. Therefore, several methods for the synthesis of quinoxalines have been reported in the literature[2]. However, some of these reported methods are associated with one or more disadvantages such as harsh reaction conditions, use of expensive reagents, use of environmentally toxic reagents and use of large amount solid supports, which result in the generation of a large amount of toxic waste. Thus, several previous methods have been excluded from practical applications due to environmental and economic considerations. Hence, there is still a need to develop efficient methods for the synthesis of quinoxaline derivatives. Herein, we disclose a green process for efficient condensation of 1, 2-diketone with 1, 2-diamine catalyzed by Cetyltrimethylamoniumhydrogensulfate (CTAHS), a Brønsted acid surfactant, in aqueous media at room temperature (Scheme). The solid quinoxaline product was precipitated as reaction proceed and was achieved in high to excellent yield by addition water to reaction mixture and a simple filtration.