1,4-Bis(bromomethyl)benzene

white to light yellow crystal powde

2.3.2.1 Synthesis of 1, 4-bis(bromomethyl)benzene 4 In a 250 ml round bottom flask p-xylene 1 (5 ml, 40.78 mmol), and 70 ml of carbon tetrachloride were taken and then the flask was kept on an oil bath. N-bromosuccinimide (29.86 g, 167.80 mmol) and benzoyl peroxide (5.83 g, 24.08 mmol) were added into the flask and the whole solution was refluxed for 12 h at 70 °C. After the completion of reaction, the solution was cooled to room temperature and thus formed solid imide which in turn was removed by filtration. From the filtrate, the solvent was eliminated by distillation to give the pale yellow solid, viz., 1, 4-bis(bromomethyl)benzene 4. The yield was 90percent and the melting point was 142-144 °C. FT-IR (KBr, cmIt was prepared as a method previously described [27]. Briefly, 29.6 mL (0.24 mol) dry p-xylene was introduced into the flask, stirring at 140 °C in an oil bath. When the xylene starts boiling, 24.6 mL (0.48 mol) of dry bromine were added dropwise over 2 h and using a 300-watt tungsten lamp lighted reaction. To continued at 140 °C for an additional 3 h. Then, the mixture is cooled over night and dissolved in resultant of warm chloroform. And the precipitate was dissolved in fresh chloroform solution and recrystallizing in it. Yield: 55.4 g (87.4percent). m.p.:143–146 °C. Anal. Calc. for CTo the solution of 2.0 mL (21.82 mmol) 1, 4-dimethylbenzene in CClp-Xylene (6.2 mL, 50 mmol) and N-bromosuccinimide (NBS) (21.3 g, 110 mmol) were added to a solution of CCl119 g of 50percent hydrogen peroxide (1.75 mol)Slowly add to 300 g in an ice bathOf 74 g (0.7 mol) 1, 4-xylene in DCE, 242 g (1.44 mol) of hydrobromic acid and 7 g of concentrated sulfuric acid, The resulting mixture was then irradiated with a visible light lamp (wavelength about 400 nm) for 12 hours, An organic layer (DCE) is formed, Precipitation crude product and aqueous layer, The crude product is also partially present in the organic layer.After removal of DCE from the crude product by evaporation under reduced pressure, Add 30 grams of methanol, After stirring at 60 ° C for one hour, Cool to room temperature, After filtration, 150 g of high-purity 1, 4-bis (bromomethyl) benzene was obtained (yield 80percent, purity 98.2percent).The photoreaction equipment of 100ml equipped with a stirrer and by a Liebig condenser (100 W high pressure mercury lamp), under a nitrogen atmosphere, 1H perfluorohexane (20 ml), p-xylene (5 g, 47 mmol) and bromine 8.9 g (56 mol, 1.2eq.) were charged, and were carried out under reflux (52 ) light irradiation for 18 hours. After the reaction, adding water, reducing the excess chlorine with sodium sulfite, separated, dried over sodium sulfate (Na2SO4), filtered, and the solvent removed at recrystallization of 1, 4-bis (bromomethyl) benzene 9 .4g (76percent yield). In addition, deterioration of some in the reaction solvent in the F-NMR measurement 1H- perfluorohexane was observed.0.1 g (12.2 mL) of p-xylene and 0.1 mol (17.6 g) of N-bromosuccinimide as a starting material, 36 mL of a chloride as a solvent, 2.4 g of benzoyl peroxide as an initiator, an inert gas And the reaction was carried out for 4 to 5 hours. The unreacted N-bromosuccinimide was removed by suction filtration, and the solvent was evaporated under reduced pressure. The remaining pale yellow liquid was frozen to give a pale yellow solid which was washed with an alcoholic solvent Recrystallization gave compound 1 (12.4 g) as a white solid in 47percent yieldA solution of 1.23 ml_ (10 mmol) of p-xylene, 3.54 g (20 mmol) of N-bromosuccinimide (NBS) and 45 mg (0.2 mmol) of benzoyl peroxide in 30 mL of benzene was heated under reflux (80 Under argon, p-xylene (5.04 g, 47.53 mmol), NBS (30 g) and BPO (2 g) were added to a bottle with carbon tetrachloride as a solvent and heated. While heating to 70 ° C, The solid and liquid in the bottle began to melt. After stabilization, heating was continued until the temperature reached 80 ° C. and the reaction was refluxed for 20 hours. The mixture was cooled and cooled. The upper layer was white solid and the lower layer was yellowish, cooled to 40 ° C., filtered, and the filtrate was taken into the refrigerator , After 24h, white crystals precipitated, about 5g, that is on the dibromobenzyl, yield 40percent.Under argon atmosphere, p-xylene (5.04g, 47.53mmol), NBS (30g) and BPO (2g dibenzoyl peroxide) (2g) were added to the flask with carbon tetrachloride as the solvent for heating. , When heated to 70°C, the solids and liquids in the bottle begin to melt, after stabilization, Continue heating, return to 80 °C, reflux for 20 hours, cooling and cooling, white solid on the upper layer, The lower light yellow liquid is cooled to 40°C, filtered, and the filtrate is put into the refrigerator.After 24 h, white crystals precipitated, about 5 g, ie, dibromobenzyl, with a yield of 40percent.The compounds according to the first embodiment are preferably prepared by a scheme as illustrated in Figure 1 . Reference will be made to this scheme in describing this Example. This example describes the synthesis wherein R1 and RAs described previously by Kikuchi et al.

Molecular Weight:263.96
XLogP3:3
Rotatable Bond Count:2
Exact Mass:263.89723
Monoisotopic Mass:261.89928
Heavy Atom Count:10
Complexity:73.3
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes