2,4-Dibromonitrobenzene

Light yellow powder

To 20 mL of ice-cooled and vigorously stirred concentrated sulphuric acid 20 mL of concentrated nitric acid is added drop wise. After cooling to 0 °C 11.8 g 1, 3-dibromobenzene (50 mmol) is added slowly drop wise, keeping the temperature below 20 °C (30min). The cooling is removed and the mixture is stirred at room temperature for one hour. After cooling to 0 °C 40 g of ice is added slowly in portions. The precipitate is sucked off, washed several times with ice water and dried to give 13.96 g (48.3 mmol) of the desired product as light yellow crystals (97 percent). Melting point: 54-57 °C. Add 1, 3 dibromobenzene (25g) over sulfuric fumante acid (20 mL). Stir for 5 hours at room temperature and then pour into ice-water, extract with ethyl acetate, wash with saturated aqueous sodium chloride, dry over magnesium sulfate and concentrate under reduced pressure. Crystallize the residue with methanol to provide (26.8 g, 90percent) of the desired product a light yellow solid. MS [(ES+)] : [MAZ] = 281. 90 [(M+H) +]Sulfuric acid (744 mE) and nitric acid (144 mE) were mixed. In the temperature of 00 C., 1 , 3-dibromoben- zene (300 g, 1, 270 mmol) were slowly dropped and stirred for 30 minutes. Afier completion of the reaction, ice water was slowly dropped into the mixture, and the solid was filtered and extracted using ethylacetate in several times. The organic solvent was removed, and the silica-gel column process was performed to obtain 2, 4-dibromo-1 -nitrobenzene (261 g, yield: 73percent).To an iced cold solution of 1, 3-dibromobenzene (10g, 42.3mmol) in sulfuric acid (200ml) was added portionwise ammonium nitrate (3.39g, 42.3mmol) and the mixture was stirred at 0°C for 10 minutes and then poured into water. After extraction withTo an iced cold solution of 1, 3-dibromobenzene (10g, 42.3mmol) in sulfuric acid (200ml) was added portionwise ammonium nitrate (3.39g, 42.3mmol) and the mixture was stirred at 0°C for 10 minutes and then poured into water. After extraction with CHIntermediate 7: 6-Bromo-l-methyl-lH-benzoimidazole; Step 1: 2, 4-Dibromo-l-nitro-benzene; [0309] To an ice-cold solution of 1, 3-dibromobenzene (10 g, 42.4 mmol) in concentrated sulfuric acid (200 mL) was added ammonium nitrate (3.39 g, 42.4 mmol) portionwise. The reaction mixture was stirred at OAfter putting HNOExample 13; Part A:To concentrated sulfuric acid (75 ml_) at OAfter making a bath of -4°C putting ice in aqueous solution of saturated NaCl, nitric acid (1.5 equivalents) was putted into sulfuric acid solvent, and was waited until the temperature of the reaction solvent became 0°C. 1, 3-dibromobenzene (10 g, 42.4 mmol) was putted into a dropping funnel, and was dropwised to not exceed 10°C. After 30 minutes, the reaction mixture was quenched with water. The obtained solid was filtered, was washed with purified water several times, and was filtered through column to obtain compound 7-1 (7 g, 59 percent).Add 1, 3-dibromobenzene (45 g, 0.191 mol) to a 500 mL three-necked flask and add a mixed solution of sulfuric acid (133.59 g, 0.51 mol) and water (13.73 g, 0.763 mol).The solution was cooled to 0 ° C and nitric acid (32.21 g, 0.51 mol) was slowly added dropwise. When the addition was complete, the reaction system was transferred to room temperature for stirring and TLC followed.After the reaction is over, the reaction system is poured into ice water.Add 100mL ethyl acetate extraction.The aqueous phase is extracted once more with 100 mL of methylene chloride.Combine the organic phases.Drying over anhydrous sodium sulfate.Filtration and distillation of the solvent under reduced pressure, beating with petroleum ether gave 31.2 g of light yellow crystals.Yield: 58.23percent.Sulfuric acid (124 mL) and 60percent nitric acid (28 mL) were mixed, and then cooled to 0°C. Then, 1, 3-dibromobenzene (50 g, 0.21 mol) was slowly added dropwise thereto, followed by stirring for 30 minutes. After the stirring was completed, ice water was added thereto, followed by extraction with EA (300 mL). The organic layer was dried over anhydrous magnesium sulfate, followed by distillation under reduced pressure and then silica column purification, thereby obtaining Compound 11-1 (20 g, 34percent).

Medicine. Pesticide intermediates.

Molecular Weight:280.90
XLogP3:3.2
Hydrogen Bond Acceptor Count:2
Exact Mass:280.85100
Monoisotopic Mass:278.85305
Topological Polar Surface Area:45.8
Heavy Atom Count:11
Complexity:159
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes