5227-60-1

Upstream product

• 492-70-6 1,2-diphenyl-1,2-ethanediol 
• 769-11-9 2-chloro-6-nitroaniline 
• 21745-41-5 2,3-diaminochlorobenzene 
• 119-53-9 2-hydroxy-2-phenylacetophenone 
• 134-81-6 benzil 
• 5227-55-4 2,3-diphenyl quinoxaline N-oxide 
• 98-59-9 p-toluenesulfonyl chloride 
• 67-56-1 methanol 

Relevant academic research and scientific papers

Synthesis method of quinoxaline heterocyclic derivative

The invention discloses a synthesis method of a quinoxaline heterocyclic derivative. An intermolecular redox reaction and a condensation cyclization reaction are carried out on an o-nitroaniline compound and an o-diol compound under the action of a water-soluble alkali to prepare the quinoxaline heterocyclic derivative in one step. Expensive transition metal catalysts and ligands do not need to beused, the water-soluble alkali is used as an accelerant and can be removed in a water washing manner, so that the product has no transition metal residue, the product is easy to separate, the recovery rate is high, and the method is simple in condition, easy to operate and low in equipment requirement; and the water-soluble alkali is used as the accelerant, so the unique byproduct is water, the atom economy is high, and the method has good research and industrial application prospects.

Rapid, efficient and eco-friendly procedure for the synthesis of quinoxalines under solvent-free conditions using sulfated polyborate as a recyclable catalyst

An efficient and inexpensive sulfated polyborate catalyst was applied for the rapid synthesis of quinoxaline derivatives from various substituted o-phenylenediamines and 1,2-diketones/α-hydroxy ketones using sulfated polyborate is described. The catalyst has the advantage of Lewis as well as Bronsted acidity and recyclability without significant loss in catalytic activity. The key advantages of the present method are high yields, short reaction times, solvent-free condition, easy workup, and ability to tolerate a variety of functional groups, which give economical as well as ecological rewards. [Figure not available: see fulltext.]

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

Heating the title compounds 1 at reflux in acetic anhydride yields quinoxalines 3 and 4 via a presumed aryliminoiminyl radical 5, resulting from homolytic cleavage of the N-O bond in the intermediate ester 2. The observed regioselectivity of the reaction is also rationalized by implicating such a radical. (C) 2000 Elsevier Science Ltd.

THE REACTION OF QUINOXALINE- AND PHENAZINE-N-OXIDES WITH THIONYL CHLORIDE AND PARATOLUENESULFONYL CHLORIDE

2,3-Diphenylquinoxaline-N-oxide 1 with thionyl chloride gives only 5-chloro- and 6-chloroquinoxaline and very little deoxygenation.Phenazine-N5-oxide 2, in the same conditions, gives mainly 2-chlorophenazine and minor amounts of 1-chlorophenazine, but here deoxygenation is an important pathway.Freshly recrystallized para-toluenesulfonyl chloride gives a high chlorination-to-tosyloxylation ratio.All these results point to a variable ability of acid chlorides to yield homocycle chlorination or acyloxylation; this is confirmed by the observation that phenazine-N5-oxide and phosphoryl chloride give fair amounts of aryl phosphate.

An unexpected course of the Meisenheimer reaction : aryl phosphates in the reaction of phosphoryl chloride with 2,3-diphenylquinoxaline-N1-oxide.

Contrary to what is observed with other ?-deficient heteroaromatic N-oxides, the reaction of 2,3-diphenylquinoxaline-N1-oxide with OPCl3 gives only very poor yields of chlorinated quinoxalines.It is shown that the major product arises from an unprecedented attack by the nucleophilic oxygen atom of the reagent at a carbon atom of the homocycle of the O-phosphorylated N-oxide, leading ultimately to the corresponding mono- (or di-) aryl ester of phosphoric acid.Using a much smaller excess of OPCl3 and dilution of the medium with an inert solvent strongly increase the yield of chlorination products.It is suggested that, after the initial O-phosphorylation, phosphate formation might be the primary step in all the Meisenheimer reactions.