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ChemicalBook CAS DataBase List 4-BROMO-2-HYDROXYACETOPHENONE

4-BROMO-2-HYDROXYACETOPHENONE synthesis

8synthesis methods
Preparation by diazotization of 5-amino-3-bromo-2- hydroxyacetophenone, followed by hydrolysis of the obtained diazonium salt (51%).
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Yield:30186-18-6 71.9%

Reaction Conditions:

Stage #1:methylmagnesium bromide;4-bromo-2-hydroxy-benzonitrile in tetrahydrofuran;toluene at 0 - 20; for 15 h;
Stage #2: with hydrogenchloride in tetrahydrofuran;water;toluene at 0; for 2 h;Heating / reflux;

Steps:

1.3
To a stirred solution of 4-Bromo-2-hydroxy-benzonitrile (3. 6 g, 18. 2MMOL) in anhydrous THF solution (20 mL) was added methylmagnesium bromide (1. 4 M in THF/toluene, 39.0 mL, 54. 6MMOL, 3 eq) at 0 °C under argon. The reaction mixture was slowly warm up to rt and stirred for 15 h. The mixture was cooled to 0 °C and quenched by the addition of water (5 mL) followed by concentrated HCI (10 mL). The resulting solution was refluxed for 2 h before cooled down to rt. The reaction mixture was then poured into EtOAc (100 mL) and water (100 mL). The layer was separated and the organic layer was washed with water (2 x 50 mL), dried over NA2SO4, filtrated, and concentrated under reduced pressure. The residue was then subjected to silica gel chromatography (20% EtOAc/Hexane) to provide 1- (4-BROMO-2-HYDROXY-PHENYL)- ethanone (2.81 g, 71.9%) as yellow OIL. 1H-NMR (CDCI3) : 8 12.32 (s, 1H, OH), 7.57 (d, J = 8. 7HZ, 1H), 7.17 (d, J = 1,9 Hz, 1H), 7.03 (dd, J = 1.9, 8.7 Hz, 1H), 2.62 (s, 3H).

References:

BAYER PHARMACEUTICALS CORPORATION WO2005/14566, 2005, A1 Location in patent:Page/Page column 61

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