Synthesis of quinoxalines by cyclization of α-arylimino oximes of α-dicarbonyl compounds

Silica-bonded S-sulfonic acid as a recyclable catalyst for chemoselective synthesis of 1,1-diacetates

“…Some progress on the synthesis of quinoxaline derivatives has been reported in the literature, for example: the Bi-catalyzed oxidative coupling reaction [25], a tandem oxidation process using Pd(OAc) 2 or RuCl 2 -(PPh 3 ) 3 -TEMPO [26], and MnO 2 [27], heteroannulation of nitroketene N,S-arylaminoacetals with POCl 3 [28], cyclization of α-arylimino oximes compounds under refluxing condition in acetic anhydride [29]. Also, there are recent reports on the condensation of o-phenylene diamines and 1,2-dicarbonyl compounds in the presence of PbO [30] [34], metal hydrogen sulfates [35], and oxalic acid [36].…”

“…Measurements of surface area and pore size distribution were made using the Brunauer-Emmet-Teller (BET) method in a Quanta Sorb machine. The products were characterized by comparison of their spectral and physical data with those reported in literature [25][26][27][28][29][30][31][32][33][34][35][36]. 3-Mercapto-propylsilica (1, MPS) was prepared according to the previous report [3].…”

Oxalic acid as an efficient, cheap, and reusable catalyst for the preparation of quinoxalines via condensation of 1,2-diamines with α-diketones at room temperature

“…7 A number of methods have been developed for the synthesis of substituted quinoxalines. [8][9][10][11][12][13] The most common method for their preparation relies on the condensation of an aryl 1,2-diamine with a 1,2-dicarbonyl compound. 8 Furthermore, there are several synthetic routes toward quinoxalines, including Bi-catalyzed oxidative coupling of epoxides with ene-1,2-diamines, 9 heteroannulation of nitroketene N,S-aryliminoacetals with POCl 3 , 10 cyclization of α-arylimino oximes of α-dicarbonyl compounds, 11 and from α-hydroxy ketones via a tandem oxidation process using Pd(OAc) 2 or RuCl 2 -(PPh 3 ) 3 -TEMPO 12 as well as MnO 2 .…”

“…[8][9][10][11][12][13] The most common method for their preparation relies on the condensation of an aryl 1,2-diamine with a 1,2-dicarbonyl compound. 8 Furthermore, there are several synthetic routes toward quinoxalines, including Bi-catalyzed oxidative coupling of epoxides with ene-1,2-diamines, 9 heteroannulation of nitroketene N,S-aryliminoacetals with POCl 3 , 10 cyclization of α-arylimino oximes of α-dicarbonyl compounds, 11 and from α-hydroxy ketones via a tandem oxidation process using Pd(OAc) 2 or RuCl 2 -(PPh 3 ) 3 -TEMPO 12 as well as MnO 2 . 13 Nevertheless, most of these methods suffer one or more of the following drawbacks: unsatisfactory yield, long reaction time, critical product isolation procedures, the use of expensive and detrimental metal precursors, harsh reaction conditions, and no agreement with the green chemistry protocols, which limit their use.…”

Green and Efficient Synthesis of Quinoxaline Derivatives via Ceric Ammonium Nitrate Promoted and in Situ Aerobic Oxidation of .ALPHA.-Hydroxy Ketones and .ALPHA.-Keto Oximes in Aqueous Media

“…In addition, improved methods have been developed for the synthesis of quinoxaline derivatives including the Bi-catalyzed oxidative coupling of epoxides and ene-1,2-diamines, 17) and the cyclization of a-arylimino oximes of a-dicarbonyl compounds under reflux conditions in acetic anhydride. 18) Moreover, Taylor and his co-worker 19,20) have shown that quinoxalines can be produced in one-pot process commencing from a-hydroxy ketones using a manganese dioxide-mediated or aerobic oxidation palladium acetate-catalyzed tandem oxidation process with in situ trapping of adicarbonyls with aromatic 1,2-diamines. These oxidation and condensation reactions into a single operation provide a significant improvement to existing procedure.…”