1,4-dibromo-2,5-dimethylbenzene

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 31.2 ml of (50 mmol) of a 1.6 molar n-butyl lithium solution in hexane are added dropwise to a solution of 13.5 g (50 mmol) of 2,5-dibromo-p-xylene in 100 ml of tetrahydrofuran cooled to −78° C., the mixture is stirred for 30 minutes and then combined with 4.5 ml of (50 mmol) of isobutyronitrile. The reaction mixture is allowed to come back slowly to ambient temperature, stirred for 1 hour, then combined with 50 ml of 2N HCl and 70 ml of diethyl ether and stirred for another 16 hours. The aqueous phase is separated off and extracted 2× with diethyl ether. The combined organic phases are dried with Na2SO4, evaporated down and the residue is purified by flash chromatography (silica gel; petroleum ether to petroleum ether/ethyl acetate=9:1). to come back slowly to ambient temperature stirred for 1 hour stirred for another 16 hours The aqueous phase is separated off extracted 2× with diethyl ether The combined organic phases are dried with Na2SO4 evaporated down the residue is purified by flash chromatography (silica gel; petroleum ether to petroleum ether/ethyl acetate=9:1)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: At −78° C., 100 ml (0.16 mol) of a 1.6 molar n-butyl lithium solution in hexane is added dropwise to a solution of 43.63 g (0.162 mol) of 2,5-dibromo-p-xylene, and stirred for one hour. Then dry carbon dioxide is passed into the solution for 4 hours. It is slowly heated to ambient temperature and stirred for 16 hours. After the slow addition of 210 ml of 2N hydrochloric acid, the phases are separated, the aqueous phase is extracted 2× with 200 ml ether, the combined organic phases are washed with conc. NaCl solution and dried with Na2SO4. After the solvent has been eliminated in vacuo the crude product is mixed with 200 ml of 2N NaOH and the brown solution obtained is extracted 3× with 100 ml of diethyl ether. The aqueous phase is acidified with conc. HCl and the precipitate which then forms is suction filtered, washed with ice water and dried. stirred for 16 hours the phases are separated the aqueous phase is extracted 2× with 200 ml ether the combined organic phases are washed with conc. NaCl solution dried with Na2SO4 is mixed with 200 ml of 2N NaOH the brown solution obtained is extracted 3× with 100 ml of diethyl ether filtered washed with ice water dried

Conditions: temp:90.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 52.8 g (200 mmol) of 1,4-dibromo-2,5-Dimethyl benzene, 53.6 g (440 mmol) of phenylboronic acid, 2.3 g (2 mmol) of tetrakis(triphenylphosphine)palladium, 400 ml of 2M Na2CO3, 400 ml of EtOH and 800 ml toluene was degassed and placed under nitrogen, and then heated at 90° C. for 6 hours. After the reaction finish, the mixture was allowed to cool to room temperature. The organic layer was extracted with ethyl acetate and water, dried with anhydrous magnesium sulfate, the solvent was removed and the residue was purified by column chromatography on silica (hexane-dichloromethane) to give product 43.4 g (168 mmol, 84%) as a white solid. was degassed to cool to room temperature The organic layer was extracted with ethyl acetate and water dried with anhydrous magnesium sulfate the solvent was removed the residue was purified by column chromatography on silica (hexane-dichloromethane)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 60 g of 2,5-Dibromo-p-xylene (0.227 mole), 42.4 g of CuCN (0.568 mole) and 300 ml of dimethylformamide were added into a round-bottom flask, and then the reaction was performed at 130° C. for 12 hours. After completion of the reaction, the reaction mixture was added to the mixing solution of 300 ml of water and 300 ml of aqueous ammonia, and extracted crystal therefrom was filtered. Then, the crystal was added again to the mixing solution of 100 ml of water and 300 ml of aqueous ammonia, mixed and filtered. The obtained crystal was added to 2,000 ml of toluene, heated to dissolve, and treated with active carbon. The filtrate was evaporated in vacuum, and then 300 ml of hexane was added thereto to obtain 20 g of white crystal (0.128 mole, yield: 56%). After completion of the reaction extracted crystal therefrom was filtered Then, the crystal was added again to the mixing solution of 100 ml of water and 300 ml of aqueous ammonia mixed filtered The obtained crystal was added to 2,000 ml of toluene heated to dissolve treated with active carbon The filtrate was evaporated in vacuum 300 ml of hexane was added

Conditions: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 4 g (15 mmol, 1 eq.) of 1,4-dibromo-2,5-dimethylbenzene are solubilized in 50 mL of distilled THF, in a Schlenk tube under argon. The medium is then cooled to −78° C., then 6.6 mL (16.6 mmol, 1.1 eq.) of BuLi (2.5M in hexane) are added dropwise. After stirring at this temperature for 1 hour, 5.3 mL (68 mmol, 4.5 eq.) of freshly distilled DMF are added. The reaction medium is again stirred at this temperature for 1 hour, and then the temperature returns to ambient temperature overnight. Next, the medium is diluted with a solution of ammonium chloride and then extracted three times with ethyl acetate. The organic phases are combined, dried over magnesium sulphate, and concentrated under reduced pressure. The residue is purified by silica column chromatography (eluent: ethyl acetate/petroleum ether: 80/20), so as to give a white solid (m: 1.3 g, yield: 40%). The reaction medium is again stirred at this temperature for 1 hour to ambient temperature overnight extracted three times with ethyl acetate dried over magnesium sulphate concentrated under reduced pressure The residue is purified by silica column chromatography (eluent: ethyl acetate/petroleum ether: 80/20) so as to give a white solid (m: 1.3 g, yield: 40%)

Conditions: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 4 g (15 mmol, 1 eq.) of 1,4-dibromo-2,5-dimethylbenzene are solubilized in 50 mL of distilled THF, in a Schlenk tube under argon. The medium is then cooled to −78° C., then 6.6 mL (16.6 mmol, 1.1 eq.) of BuLi (2.5M in hexane) are added dropwise. After stirring at this temperature for 1 hour, 5.3 mL (68 mmol, 4.5 eq.) of freshly distilled DMF are added. The reaction medium is again stirred at this temperature for 1 hour, and then the temperature returns to ambient temperature overnight. Next, the medium is diluted with a solution of ammonium chloride and then extracted three times with ethyl acetate. The organic phases are combined, dried over magnesium sulphate, and concentrated under reduced pressure. The residue is purified by silica column chromatography (eluent: ethyl acetate/petroleum ether: 80/20), so as to give a white solid (m: 1.3 g, yield: 40%). The reaction medium is again stirred at this temperature for 1 hour to ambient temperature overnight extracted three times with ethyl acetate dried over magnesium sulphate concentrated under reduced pressure The residue is purified by silica column chromatography (eluent: ethyl acetate/petroleum ether: 80/20) so as to give a white solid (m: 1.3 g, yield: 40%)

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:-10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 1,4-dibromo-2,5-dimethylbenzene (5.0 g, 18.94 mmol, Aldrich) in anhydrous THF (20 mL) was cooled to about −10° C. Isopropyl magnesium chloride (3.95 mL, 2.0 M in THF, 7.9 mmol) was added. The mixture was allowed to stir at about −10° C. for about 0.25 h. Next n-butyl lithium (6.31 mL, 2.5 M in hexanes, 15.8 mmol) was added dropwise keeping the temperature at or below about 0° C. Once the addition was complete the reaction was stirred at about −10° C. for about 1 h. Next a solution of DMF in 10 mL anhydrous THF (20.52 mmol) was added dropwise keeping the temperature at or below about 0° C. The reaction was stirred at ambient temperature for about 3 hours. The reaction was poured into about 50 mL of about 5 M aqueous citric acid solution (exothermic) and stirred at room temperature for about 10 minutes. The layers were separated and the aqueous layer was extracted once with toluene (50 mL). The combined organic layers were washed with water (20 mL), then concentrated in vacuo. The residue was purified by column chromatography (SiO2, diethyl ether/petroleum ether 5:95) to give 4-bromo-2,5-dimethylbenzaldehyde (3.66 g, 17.18 mmol, 91%) as a pale crystalline solid: 1H-NMR (CDCl3, Bruker 400 MHz) δ 2.43 (3 H, s); 2.60 (3 H, s); 7.47 (1 H, s); 7.63 (1 H, s) 10.2 (1 H, s). below about 0° C Once the addition was stirred at about −10° C. for about 1 h below about 0° C The reaction was stirred at ambient temperature for about 3 hours stirred at room temperature for about 10 minutes The layers were separated the aqueous layer was extracted once with toluene (50 mL) The combined organic layers were washed with water (20 mL) concentrated in vacuo The residue was purified by column chromatography (SiO2, diethyl ether/petroleum ether 5:95)