4,4′-Dibromobenzil

yellow crystalline powder

[Step 1] A synthesis method of 2, 3-bis(4-bromophenyl)quinoxaline is described. A synthesis scheme of 2, 3-bis(4-bromophenyl)quinoxaline is represented by (a-1). 30.2 g of [Step 1] Synthesis of 2, 3-bis(4-bromophenyl)quinoxaline A synthesis method of 2, 3-bis(4-bromophenyl)quinoxaline is described. A synthesis scheme of 2, 3-bis(4-bromophenyl)quinoxaline is shown in (B-1). Under a nitrogen gas stream, 30.2 g (82.0 mmol) of 4, 4'-dibromobenzyl, 9.31 g (86.1 mmol) of 1, 2-phenylenediamine, and 300 mL of chloroform were put into a 500 mL three-neck flask. This solution was refluxed at 80 C. for 5 hours. After a reaction was completed, the reaction solution was cooled to room temperature and washed with water. A water layer was extracted with chloroform, and the extracted solution was combined with an organic layer and then dried with magnesium sulfate. After drying, the mixture was subjected to suction filtration and the filtrate was concentrated. An obtained solid was dissolved in toluene, and this solution was subjected to suction filtration through Florisil, celite, and alumina. The filtrate was concentrated, and 30 g of a white, powdery solid of 2, 3-bis(4-bromophenyl)quinoxaline, which was a target matter, was obtained with the yield of 99%.A synthetic scheme of 2, 3-bis(4-bromophenyl)quinoxaline is shown in (C-1). In a 500 mL three-necked flask were placed 30 g (82 mmol) of Under a stream of nitrogen, 30.2 g (82.0 mmol) of General procedure: To a mixture of 1, 2-dicarbonyl compound 1a-e (1.0 mmol) and 1, 2-diamine 2a-b (1.0 mmol) inethanol (5 mL), supported CoNP (0.033g, 1 mol%) was added and the mixture was refluxed in anopen flask for 90 min. Reactions were monitored by thin layer chromatography (TLC) until totaldisappearance of the starting material. After completion of the reaction, the reaction mixture wascooled to room temperature, and resulting solid was collected by filtration and dissolved in ethylacetate (10 mL). The supported catalyst was recovered by filtration. After evaporation of solvent, theresulting solid product was purified by crystallization in ethanol.A chloroform solution (200 mL) of 30.0 g (81.5 mmol) of In a nitrogen atmosphere, a chloroform solution (200 mL) containing 30.0 g (81.5 mmol) of 4, 4'-dibromobenzyl and 9.00 g (83.2 mmol) of o-phenylenediamine was refluxed at 80 C for three hours. The reacted solution was washed with water after being cooled to a room temperature. An aqueous layer was extracted with chloroform and the solution obtained by extraction was washed with saturated saline together with the organic layer. After the organic layer was dried with magnesium sulfate, the mixture was filtered and the filtrate was condensed. Accordingly, 33 g (yield: 92 %) of objective 2, 3-bis(4-bromophenyl)quinoxaline was obtained as a white solid.In a nitrogen atmosphere, 4, 4'-dibromo-benzyl 30.0 g (81.5 mmol)And a chloroform solution (200 mL) containing o- phenylenediamine 9.00 g (83.2 mmol)It was refluxed for 3 hours at 80 . After cooling the reaction solution to room temperature, the reaction solution was washed with water. Extracting the resultant aqueous phase ( ) with chloroform, and the extract solution to the organic phase three () were combined and saturated brineIt was determined. After drying the organic phase over magnesium sulfate, a result of the suction filtration, and the filtrate was concentrated and the mixture, the target product, 2, 3-bis (4-bromophenyl) quinoxaline 33 g (92% yield) as a white solid obtained.General procedure for the synthesis of quinoxaline and pyrido[2, 3-b]pyrazine: In a small Schlenk tube, 1, 2-diamine (1 mmol), 1, 2-diketone (1 mmol), PTSA (5 mol %), and 40% aq NaPTS (5 ml) were taken and the reaction mixture was stirred at room temperature. The reaction process was monitored by thin layer chromatography (TLC). After completion of the reaction, the mixture was diluted with water (20 mL). The filtrate was washed with water and dried affording the corresponding products.General procedure: To a mixture of 1, 2-diaminobenzene (1 mmol) and 1, 2-dicarbonyl compound (1 mmol) in ethanol (10 mL), catalyst (10 mol%) was added and the solution was refluxed for appropriate time. The progress of the reaction was monitored by TLC. After completion of the reaction, ethyl acetate was added to the solidified mixture and the insoluble catalyst was separated by filtration. After evaporation of the solvent, the resulting solid product was recrystallized from ethanol to obtain pure product.General procedure: To a mixture of 1, 2-diaminobenzene (1 mmol) and 1, 2-dicarbonyl compound (1 mmol), RHA-SO3H (15 mg) was added and the mixture was stirred at room temperature for the appropriate time. The progress of the reaction was monitored by TLC (EtOAc: n-hexane 2:8). After completion of the reaction, ethyl acetate (20 mL) was added to the mixture and the solid catalyst was separated. Then the solvent was evaporated and the resulting solid product was recrystallized from ethanol, producing the pure product in high yields.General procedure: A mixture of 1, 2-diamine (1 mmol) and alpha-dicarbonyl compound (1 mmol) was intimately mixed with pre-activated KF-alumina (1:4) (0.5 g) (Basic; Grade: Brockmann 1, and activated by heating under vacuum at 150 C until bubbling ceases and then cooled to room temperature under vacuum) and stirred solid mixture with a magnetic spin bar at room temperature for hours as indicated in refPreviewPlaceHolderTable 4. After the reaction was complete, the solid mixture washed with diethyl ether (3 × 10 mL) and the solid was filtered off. The filtrate was concentrated and passed through a short column of silica gel to afford the quinoxalines. The desired product was pure on TLC and characterized by spectral (1H and 13C NMR) data and compared to those reported.[Step 1] A synthesis method of 2, 3-bis(4-bromophenyl)quinoxaline is described.; A synthesis scheme of 2, 3-bis(4-bromophenyl)quinoxaline is represented by (a-1). [Show Image] 30.2 g of Synthesis of Quinoxaline Dihalide Member (Intermediate 1); 1, 2-Phenylenediamine (2.9 g), and 4, 4'-dibromobenzyl (11 g) are placed into a three-necked flask having 500 ml capacity and provided with a thermometer, a condenser, and a magnetic stirrer, and the mixture is dissolved into 200 ml of isopropylether. The solution is heated to reflux at a room temperature for 1 hour while the solution is magnetically stirred. It is confirmed by means of TLC (hexane/ethyl acetate=3/1) that the spots of 1, 2-phenylenediamine disappear, and then, the product is cooled to a room temperature. Since a crystal separates out during the reaction, it is filtered by means of suction filtration. The crystal is further washed with 50 ml of methanol, and then the crystal is subjected to vacuum drying at 70 C. for 15 hours to obtain 10 g of the [intermediate 1].General procedure: A mixture of 2-nitro aniline (1 mmol), hydrazine monohydrate (2.2 mmol) and GO (20 mg) was taken in a screw-capped glass tube and stirred the reaction mixture for 3-4 h at 100 C temperature. After the complete reduction (as monitored by tlc and by the colour change of the reaction mixture from yellow to total black), 1, 2-dicarbonyl compound (or alpha-hydroxy ketone) (1 mmol) was added to the reaction mixture and stirred for few hours at 60 C (80 C for alpha-hydroxy ketone), as mentioned in the Table 2. After completion of the reaction (checked by tlc), the reaction mixture was cooled to room temperature. Water and ethyl acetate were added to the reaction mixture and centrifuge (5000 rpm) the whole reaction mixture to separate the GO (which is now converted to rGO). This process was repeated for three times. The combined organic-aqueous part was then taken in a separating funnel and the organic layer was separated from aqueous layer, and finally dried over anhydrous Na2SO4. Evaporation of the solvent afforded the desired quinoxaline (satisfactorily pure), which was further purified by passing through a short column of silica gel and using the light petroleum ether:ethyl acetate (97:3) as the eluent. All products were characterized by 1H, 13C NMR data and compared with the reported melting points for known solid compounds.

Molecular Weight:368.02
XLogP3:4.8
Hydrogen Bond Acceptor Count:2
Rotatable Bond Count:3
Exact Mass:367.88706
Monoisotopic Mass:365.88910
Topological Polar Surface Area:34.1
Heavy Atom Count:18
Complexity:282
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes