1,5-DIBROMO-2,4-DIFLUOROBENZENE

Preparation 131 , 5-dibromo-2, 4-difluorobenzeneTo a solution of l-bromo-2, 4-difluorobenzene (19.3 mL, 171 mmol) in CH2CI2 (100 mL) was added iron (3.15 g, 56 mmol). To this stirred suspension was added a solution of bromine (1 1 mL, 214 mmol) in CH2CI2 (25 mL) drop wise over 30 min. The resulting mixture was stirred at rt overnight. The reaction mixture was slowly poured into saturated aqueous NaPreparation 1 1 , 5-dibromo-2, 4-difluorobenzene To a solution of l-bromo-2, 4-difluorobenzene (19.3 mL, 171 mmol) in CH2CI2 (100 mL) was added iron (3.15 g, 56 mmol). To this stirred suspension was added a solution of bromine (1 1 mL, 214 mmol) in CH2CI2 (25 mL) drop wise over 30 min. The resulting mixture was stirred at rt overnight. The reaction mixture was slowly poured into saturated aqueous Na39 mmol (7.52 g) of 1-bromo-2, 4-difluorobenzene were loaded into a 100-ml flask, and the temperature of the 1-bromo-2, 4-difluorobenzene was heated to 60°C. Next, 0.15 g of iron was added, and then 39 mmol (6.23 g) of bromine were dropped over 3 hours while the temperature of the mixture was kept at 60°C. After the completion of the dropping, the resultant was further subjected to a reaction at 60°C for 2 hours. After the temperature of the resultant reaction liquid had been cooled to room temperature, the reaction liquid was charged into a cold aqueous solution of sodium hydroxide, and the reaction product was extracted with hexane. An organic layer was washed with pure water and a saturated sodium chloride solution, and was dehydrated with anhydrous sodium sulfate. After that, the solvent was removed. The resultant residue was purified by means of silica gel chromatography (developing solvent: hexane), whereby 8.81 g of a compound A as colorless oil were obtained (84percent yield).2, 4-difluorobromobenzene (3 g, 15.5 mmol) and 260 mg of iron filings were placed in a two-neck flask, and 15 ml of dichloromethane was then added thereto. The two-neck flask was cooled in an ice bath, and a solution including bromine (1 ml, 18.7 mmol) and 15 ml of dichloromethane was added dropwise to the two-neck flask using an isobaric funnel. Next, the contents in the two-neck flask were heated under reflux for 3 hours. During heating, brown gas was produced. Then, the temperature was reduced to 20° C., and 50 ml of a sodium metabisulfite (NaIron powder (16.49 g, 291 mmol) is added to 1-bromo-2, 4-difluorobenzene (110 mL, 968 mmol) in 1, 2-dichloroethane (968 mL) in a 3-neck flask at ambient temperature under a stream of nitrogen. A solution of bromine (59.7 mL, 1.16 mol) in 1, 2-dichloroethane (968 mL) is added dropwise over 1 hour and the reaction mixture is stirred at ambient temperature for 18 h. The reaction mixture is cooled to 0° C. and a saturated aqueous solution of sodium bisulfate (1.11 L, 533 mmol) is added portionwise and the mixture is separated. The aqueous phase is extracted with dichloromethane. The organic layer is washed with a saturated aqueous solution of sodium bicarbonate, water, and brine. The organic layer is dried over sodium sulfate, and the solvent is removed under reduced pressure to give a residue purified with a pad of silica using diethyl ether to give the title compound (229 g, 76percent). Preparation 131 , 5-dibromo-2, 4-difluorobenzeneTo a solution of l-bromo-2, 4-difluorobenzene (19.3 mL, 171 mmol) in CH2CI2 (100 mL) was added iron (3.15 g, 56 mmol). To this stirred suspension was added a solution of bromine (1 1 mL, 214 mmol) in CH2CI2 (25 mL) drop wise over 30 min. The resulting mixture was stirred at rt overnight. The reaction mixture was slowly poured into saturated aqueous Na2S203 (200 mL), and the resulting mixture was stirred at rt for 30 min. This was extracted with CH2C12 (3 x 80 mL). The combined extracts were washed with brine, dried over MgS04, filtered and concentrated in vacuo to give 1, 5-dibromo- 2, 4-difluorobenzene (40 g, 86 % yield) as a brown oil. XH NMR (500 MHz, CHLOROFORM-d) delta 7.79 (t, J=7.0 Hz, 1H), 7.00 (t, J=8.2 Hz, 1H).Preparation 1 1 , 5-dibromo-2, 4-difluorobenzene To a solution of l-bromo-2, 4-difluorobenzene (19.3 mL, 171 mmol) in CH2CI2 (100 mL) was added iron (3.15 g, 56 mmol). To this stirred suspension was added a solution of bromine (1 1 mL, 214 mmol) in CH2CI2 (25 mL) drop wise over 30 min. The resulting mixture was stirred at rt overnight. The reaction mixture was slowly poured into saturated aqueous Na2S203 (200 mL), and the resulting mixture was stirred at rt for 30 min. This was extracted with CH2C12 (3 x 80 mL). The combined extracts were washed with brine, dried over MgS04, filtered and concentrated in vacuo to give 1, 5-dibromo- 2, 4-difluorobenzene (40 g, 86 % yield) as a brown oil. XH NMR (500 MHz, CHLOROFORM-d) delta 7.79 (t, J=7.0 Hz, 1H), 7.00 (t, J=8.2 Hz, 1H).39 mmol (7.52 g) of 1-bromo-2, 4-difluorobenzene were loaded into a 100-ml flask, and the temperature of the 1-bromo-2, 4-difluorobenzene was heated to 60C. Next, 0.15 g of iron was added, and then 39 mmol (6.23 g) of bromine were dropped over 3 hours while the temperature of the mixture was kept at 60C. After the completion of the dropping, the resultant was further subjected to a reaction at 60C for 2 hours. After the temperature of the resultant reaction liquid had been cooled to room temperature, the reaction liquid was charged into a cold aqueous solution of sodium hydroxide, and the reaction product was extracted with hexane. An organic layer was washed with pure water and a saturated sodium chloride solution, and was dehydrated with anhydrous sodium sulfate. After that, the solvent was removed. The resultant residue was purified by means of silica gel chromatography (developing solvent: hexane), whereby 8.81 g of a compound A as colorless oil were obtained (84% yield).2, 4-difluorobromobenzene (3 g, 15.5 mmol) and 260 mg of iron filings were placed in a two-neck flask, and 15 ml of dichloromethane was then added thereto. The two-neck flask was cooled in an ice bath, and a solution including bromine (1 ml, 18.7 mmol) and 15 ml of dichloromethane was added dropwise to the two-neck flask using an isobaric funnel. Next, the contents in the two-neck flask were heated under reflux for 3 hours. During heating, brown gas was produced. Then, the temperature was reduced to 20 C., and 50 ml of a sodium metabisulfite (Na2S2O5) aqueous solution (10%) was mixed with the contents in the two-neck flask by stirring for 1 hour for terminating the reaction therein. Thereafter, the contents in the two-neck flask were washed several times with deionized water to collect an organic layer, the organic layer was dehydrated using sodium sulfate (Na2SO4), and the solvent in the organic layer was removed, followed by column chromatography (SiO2, n-hexane), thereby obtaining white crystals (3.5 g, 83% yield). (0067) The spectrum analysis for the white crystals is: 1H NMR (400 MHz, CDCl3): delta 7.74 (t, J=7.6 Hz, 1H), 6.96 (t, J=8.0 Hz, 1H); 19F NMR (376 MHz, CDCl3, 298 K): delta -103.8 (dd, J=7.5 Hz, J=7.5 Hz). The white crystals were confirmed to be Compound L3-1 having a chemical structure represented byIron powder (16.49 g, 291 mmol) is added to 1-bromo-2, 4-difluorobenzene (110 mL, 968 mmol) in 1, 2-dichloroethane (968 mL) in a 3-neck flask at ambient temperature under a stream of nitrogen. A solution of bromine (59.7 mL, 1.16 mol) in 1, 2-dichloroethane (968 mL) is added dropwise over 1 hour and the reaction mixture is stirred at ambient temperature for 18 h. The reaction mixture is cooled to 0 C. and a saturated aqueous solution of sodium bisulfate (1.11 L, 533 mmol) is added portionwise and the mixture is separated. The aqueous phase is extracted with dichloromethane. The organic layer is washed with a saturated aqueous solution of sodium bicarbonate, water, and brine. The organic layer is dried over sodium sulfate, and the solvent is removed under reduced pressure to give a residue purified with a pad of silica using diethyl ether to give the title compound (229 g, 76%). 1H NMR (400 MHz, CDCl3) delta 7.70 (dd, J=4.6, 6.8 Hz, 1H), 6.95-6.92 (m, 1H).Under ice cooling, a solution of 25.35 g of 1-bromo-2, 4-difluorobenzene in 100 mL of concentrated sulfuric acid was added with 25.7 g of N-bromosuccinimide, and stirred for 30 minutes at this temperature and for 2 days at room temperature. After cooling on ice, the reaction solution was added with ice, and extracted with 300 mL of diethyl ether. The organic layer was successively washed with water, saturated aqueous sodium hydrogen carbonate and saturated brine, and then dried over anhydrous magnesium sulfate. The solvent was evaporated, and the resulting crude product was purified and separated by silica gel column chromatography (n-hexane), to afford 34.6 g of the title compound as a colorless oil.1H-NMR ( 400 MHz, CDCl3 ) delta 6.99 ( 1H, t, J = 8.4 Hz ), 7.77 ( 1H, t, J = 6.8 Hz )A total of 1.6 g of 1-bromo-2, 4-difluorobenzene was suspended in 8.29 ml of sulfuric acid, and 1.62 g of N-bromosuccinimide was added under ice-cooling. After stirring at room temperature for 17 hours, the reaction mixture was poured onto ice-water and extracted with ethyl acetate. The resulting organic layer was washed with saturated aqueous sodium hydrogencarbonate solution and brine, dried over magnesium sulfate and the solvent was evaporated. The residue was purified and separated by silica gel column chromatography (hexane), to give 2.18 g of the title compound as a pale yellow oil.1H-NMR ( 400MHz, CDCl3 ) d 6.99 ( 1H, t, J = 8. 0 Hz ), 7.77 ( 1H, t, J = 6. 8 Hz )

Molecular Weight:271.88
XLogP3:3.5
Hydrogen Bond Acceptor Count:2
Exact Mass:271.84708
Monoisotopic Mass:269.84913
Heavy Atom Count:10
Complexity:108
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes