A rapid synthesis of quinoxalines starting from ketones

An overview of quinoxaline synthesis by green methods: recent reports

Quinoxalines and their derivatives belong to an important class of bicyclic aromatic heterocyclic system, also known as benzopyrazines, containing a benzene ring and a pyrazine ring. They have attracted considerable attention over the years due to their potential biological and pharmaceutical properties. A wide range of synthetic strategies is reported in this significant area of research. The present review showcases recent research advances in the synthesis of quinoxaline derivatives following environmentally benign approaches.

One-Pot Synthesis of α-Ketoamides from α-Keto Acids and Amines Using Ynamides as Coupling Reagents

A one-pot strategy for α-keto amide bond formation have been developed by using ynamides as coupling reagents under extremely mild reaction conditions. Diversely structural α-ketoamides were afforded in up to 98% yield for 36 examples. This reaction features advantages such as practical coupling procedure, wide functional group tolerance, and extremely mild conditions and has potential applications in synthetic and medicinal chemistry.

Facile Synthesis of Quinoxaline-2-thiol and Quinoxaline from α-Oxosulfines and o-Arylenediamines

A series of quinoxaline-2-thiols and quinoxalines were prepared in moderate to good yields from various phenacyl sulfoxides bearing 1-methyl-1H-tetrazole and o-arylenediamines. The proposed reaction mechanism involves generation of sulfines from the phenacyl sulfoxides bearing 1-methyl-1H-tetrazole through thermolysis elimination. Then, site-selective carbophilic addition of sulfines by o-arylenediamines, followed by elimination, intramolecular nucleophilic addition, and dehydration condensation. The current method provides a direct and simple strategy for the preparation of quinoxaline-2-thiols and quinoxalines.

Facile, eco-friendly, catalyst-free synthesis of polyfunctionalized quinoxalines

A novel, facile and eco-friendly synthesis of quinoxalines from [Formula: see text] and 1,2-diamines was developed. An attractive feature of this protocol is that the desired products could be generated efficiently in water and without any catalyst, which is in accordance with the aim of green chemistry. A plausible mechanism has been proposed.

I2 catalyzed tandem protocol for synthesis of quinoxalines via sp3, sp2 and sp C–H functionalization

An efficient metal-free tandem protocol for the synthesis of quinoxalines via sp³, sp² and sp C–H functionalization has been developed.

An Iodobenzene-Catalysed Domino Route toward Quinoxaline Derivatives from Simple Ketones and o-Phenylenediamines in One Pot

An iodobenzene-catalysed domino route to quinoxalines from ketones and o-phenylenediamines in one pot has been developed. This transformation consisted of the generation of Koser's generation, α-tosyloxylation of ketones, nucleophilic substitution and intramolecular dehydration with o-phenylenediamines, and dehydrogenation.

Iodine (III)-mediated one-pot synthesis of quinoxaline by tandem nucleophilic substitution and cyclisation

Quinoxaline derivatives are widely used in dyes, electroluminescent materials and organic semiconductors. An economic and convenient strategy for the synthesis of 2-phenyl-quinoxaline is described. The approach relies on the oxidation of acetophenones by [hydroxy(tosyloxy)iodo]benzene, followed by tandem nucleophilic substitution with o-phenylenediamines, dehydration cyclisation and dehydrogenation. The method was performed in two stages as a one-pot reaction.