3,5-Dibromophenol

White to brown solid

3, 5-Dibromoanisole (15.57 g, 58.5 mmol) and tetrabutylammonium bromide (1.0 g, 3.1 mmol) were suspended in 48percent hydrobromic acid (100 mL) and refluxed for 3 days. After cooling to room temperature the reaction mixture was extracted with methylene chloride (3.x.60 mL). The combined organic layers were washed with water, dried over magnesium sulfate, and evaporated. The crude product was filtered over a pad of silica gel (ethyl acetate/heptane 10:1). After removal of the solvent, 14.23 g (97percent of 3, 5-dibromophenol was obtained as pale brown needles.(b) 3, 5-Dibromophenol. 3, 5-Dibromoanisole (15.57 g, 58.5 mmol) and tetrabutylammonium bromide (1.0 g, 3.1 mmol) were suspended in 48percent hydrobromic acid (100 mL) and refluxed for 3 days. After cooling to room temperature the reaction mixture was extracted with methylene chloride (3.x.60 mL). The combined organic layers were washed with water, dried over magnesium sulfate, and evaporated. The crude product was filtered over a pad of silica gel (ethyl acetate/heptane 10:1). After removal of the solvent, 14.23 g (97percent of 3, 5-dibromophenol was obtained as pale brown needles.[0295] (b) 3, 5-Dihromophenol. 3, 5-Dibromoanisole (15.57 g, 58.5 mmol) and tetrabutylammonium bromide (1.0 g, 3.1 mmol) were suspended in 48percent hydrobromic acid (100 mL) and refluxed for 3 days. After cooling to room temperature the reaction mixture was extracted with methylene chloride (3x60 mL). The combined organic layers were washed with water, dried over magnesium sulfate, and evaporated. The crude product was filtered over a pad of silica gel (ethyl acetate/heptane 10:1). After removal of the solvent, 14.23 g (97percent of 3, 5-dibromophenol was obtained as pale brown needles.To a 250 mL two-necked flask was added 3, 5-dibromoanisole (9) (5 g, 18.8 mmol, 1 eq.) Under argon, Anhydrous CH2Cl2 (80 mL) was added, BBr3 (3.5 mL, 37.6 mmol, 2 eq.) Was added dropwise at 0 ° C and maintained at 0 ° C for 3 hours and then allowed to warm to room temperature, The reaction was stopped after darkening for 2 days. The reaction was extracted with CH2Cl2 (50 mL x 3) Combine organic phase, Distilled water (50 mL x 3), Dried over anhydrous magnesium sulfate, The magnesium sulfate was removed by filtration, Steaming the solvent, The residue was purified by silica gel column chromatography (eluent: ether / petroleum ether = 1/9) 4.2 g of a white solid, Yield 90percent. Mp = 86-89 ° C.Aluminium chloride (11.7 g, 87.6 mmol) was added in portions to a solution of 1, 3-dibromo-5-benzyloxybenzene (10.0 g, 29.2 mmol; see step (i) above) and N, N-dimethylaniline (35.4 g, 292 mmol) in CHAluminium chloride (11.7 g, 87.6 mmol) was added in portions to a solution of 1, 3- dibromo-5-benzyloxybenzene (10.0 g, 29.2 mmol; see step (i) above) and [N, N-] dimethylaniline (35.4 g, 292 mmol) in CH2CI2 (100 mL) at room temperature under a nitrogen atmosphere. After 30 min, the mixture was partitioned with IN HCI (300 mL) and EtOAc (5 x 150 mL). The combined organic extracts were washed with saturated [NAHC03] (150 mL) and brine (150 mL) then, dried [(NA2SO4), ] filtered and concentrated in vacuo. Flash chromatography on silica gel eluting with Hex: EtOAc (9: 1) afforded the sub- title compound (6.1 g, 82percent) as a white solid. 'H NMR (300 MHz, [CDCI3)] 8 7.21 (s, 1H), 6.97 (s, 2H), 5.88 (bs, 1H).Pentabromophenol (1.0 g, 2.05 mmol) and AICIPentabromophenol (1.0 g, 2.05 mmol) and AlCl3 (4.1 g, 30.75 mmol) were mixed in toluene (20 mL) and heated at reflux temperature under a nitrogen atmosphere overnight. The reaction mixture was cooled, cautiously added to ice, filtered and the filtrate was extracted with EtOAc (3 50 mL). The organics were dried (Na2SO4) and concentrated in vacuo. The residue obtained was purified by chromatography on silica gel with EtOAc:heptane (1:4, v/v) as eluent to afford the title compound as a white solid (230 mg, 0.91 mmol, 45percent).

Molecular Weight:251.90
XLogP3:3.5
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:1
Exact Mass:251.86084
Monoisotopic Mass:249.86289
Topological Polar Surface Area:20.2
Heavy Atom Count:9
Complexity:87.1
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes