2-Bromo-6-nitrobenzaldehyde

his example describes the synthesis of Aldehyde 10: To a stirred solution of 9 (4.94 g, 22.3 mmol) and DMF (22.3 mL) was added DMF'DMA (8.18 g, 9.59 mL, 68.6 mmol). After heating at 135°C for 16 h, the dark red solution was cooled to 0°C and added to a rapidly stirred solution OfNaIOThe compound (II) o-nitrobenzaldehyde (0.80 g, 5.30 mmol) and concentrated sulfuric acid (98 wtpercent, 6.4 ml) were placed in a reaction flask and stirred under a cold well for 10 minutes.Then, NBS (1.13 g, 6.36 mmol) was slowly added and stirred for 5 minutes, and finally transferred to an oil bath at 45 ° C and allowed to react under light for 45 minutes.After the reaction was completed, it was cooled to room temperature, and the reaction mixture was poured into crushed ice and quenched, and then extracted with ethyl acetate (50 ml).Wash with saturated aqueous sodium hydrogencarbonate (50 ml), dry over anhydrous sodiumdry, Obtained 281 mg of bromo o-nitrobenzaldehyde (III) as a brownish yellow solid, yield 92.0percent, purity ≥98percent.(28-6) (28-6) Treatment of 1 (986 mg, 6.53 mmol) with NBS (878 mg, 4.93 mmol) in H2SO4 (conc. 5.0 mL), as described in the paper gave after chromatography (hexanes/EtOAc, 8:2) the following fractions in order of elution: (I) 4-bromo-2-nitrobenzaldehyde (2)N-Bromosuccinimide (NBS) (1.48 g, 8.32 mmol) was added to a solution of 1 (1.01 g, 6.71 mmol) in H2SO4 (concentrated 5.0 mL). The resulting mixture was stirred at ambient temperature (3 h). The reaction was quenched with ice and extracted with ethyl acetate (320mL). The combined organic phases were washed with saturated NaCl (aqueous, 30 mL), dried (MgSO4), and filtered through a silica gel plug, and the solvents were evaporated under reduced pressure. The resulting brown oil was purified by column chromatography (hexanes=EtOAc, 8:2) to afford the following fractions in order of elution: (I) 7 (28 mg, 0.09 mmol, 1percent) as an off-white solid; (II) 2 (328 mg, 21percent), 4 (140 mg, 9percent), and 3, 4-dibromo-2-nitrobenzaldehyde (6) (94 mg, 5percent); (III) 5 (310 mg, 20percent), 8 (65 mg, 3percent), 1 (168 mg, 17percent); (IV) 3 (54 mg, 0.23 mmol, 4percent).Treatment of 1 (459 mg, 3.03 mmol) and NBS (677 mg, 3.80 mmol) in H2SO4 (3.0 mL) at 60 oC as described above afforded the following fractions in order of elution: (I) 7 (21 mg, 0.07 mmol, 2percent); (II) 2 (66 mg, 9percent) and 4 (24 mg, 3percent); (III): 2 (5 mg, 0.7percent) and 3, 4-dibromo-2-nitrobenzaldehyde 6 (85 mg, 9percent); (IV) 5 (59 mg, 8percent), 8 (13 mg, 1percent), and 1 (18 mg, 4percent); (V) 3 (20 mg, 0.09 mmol, 3percent).Treatment of 1 (504 mg, 3.33 mmol) and NBS (1.48 g, 8.30 mmol) in H2SO4 (3.0 mL) as described above provided after purification by chromatography (hexanes/EtOAc, 85:15) the following fractions in order of elution: (I) 7 (65 mg, 0.21 mmol, 9percent); (II) 2 (153 mg, 20percent), 4 (58 mg, 8percent), and 6 (128 mg, 12percent); (III) 5 (108 mg, 14percent), 8 (129 mg, 13percent), and 1 (17 mg, 3percent); (IV) 3 (57 mg, 0.25 mmol, 8percent).Compound bromo-o-nitrobenzaldehyde (III) (0.229 g, 1.00 mmol) and 4-tert-butylphenylboronic acid (IV-1) (0.267 g, 1.5 mmol), Pd(dppf)Cl2 (73.1 mg, 0.1) Mm), K2CO3 (0.273 mg) and toluene (10 ml) were placed in a reaction flask, and the reaction was stirred under reflux at 120 ° C for 12 hours.After the reaction was completed, it was cooled to room temperature, and the reaction mixture was extracted with methylene chloride.The filtrate was concentrated under reduced pressure, and the obtained concentrate was subjected to silica gel column chromatography, with a mixture of petroleum ether and ethyl acetate at a volume ratio of 9:1 as an eluent.Collect the eluate containing the target compound, distill off the solvent and dry.The compound (V-1) was obtained in an amount of 0.170 g, a yield of 60percent, and a purity of '98percent.