4-溴-2,5-二甲基苯甲醛

反应条件: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 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%)

反应条件: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 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%)

反应条件: temp:-10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 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)

反应条件: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: 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%)