ChemicalBook CAS DataBase List 3-bromo-5-methylbenzoic acid

3-bromo-5-methylbenzoic acid synthesis

9synthesis methods

Product Name:3-bromo-5-methylbenzoic acid
CAS Number:58530-13-5
Molecular formula:C8H7BrO2
Molecular Weight:215.04

1-bromo-3,5-dimethylbenzene (15 g, 81 mmol, 1.0 eq) in a mixture of pyridine (133 mL) and H2O (83 mL) was heated to 80°C. KMnO4 (25.6 g, 162 mmol, 2.0 eq) was added in portions over 45 min. After the addition was completed, heating was continued at 80°C for 1.5 h. The hot solution was then filtered, and the filtrate was acidified by addition of concentrated hydrochloric acid. The aqueous solution was extracted with EtOAc and the combined organic extracts washed with water and brine, dried (Na2SO4), filtered and evaporated in vacuo. The residue was purified by column chromatography (CH2Cl2 : MeOH, 80:1 to 40:1) to give 3-bromo-5-methylbenzoic acid. White solid, yield (5.2 g, 29 %). LC-MS: m/z 212.9, 215 [M+H]+. 1H NMR (400 MHz, MeOD) δ 7.91 (s, 1H), 7.79 (s, 1H), 7.57 (s, 1H), 2.38 (s, 3H).
synthesis of 3-bromo-5-methylbenzoic acid

synthesis of 3-bromo-5-methylbenzoic acid

648439-19-4
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$45.00/100mg

58530-13-5
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$8.00/1g

Yield: 60%

Reaction Conditions:

with potassium permanganate in water;acetone for 1 h;Reflux;

Steps:

43 3-Bromo-5-methylbenzoic acid
Example 43 3-Bromo-5-methylbenzoic acid A solution of KMnO₄ (39.3 g, 249 mmol) in water (600 mL) was added slowly to a solution of (3-bromo-5-methylphenyl)methanol (25.0 g, 124 mmol) in acetone (500 mL). The mixture was kept at reflux for 60 mins. After cooling to room temperature, the mixture was acidified with HCl (2N, 100 mL). A brown precipitate formed and was dissolved by adding a solution of saturated sodium bicarbonate (100 mL); then acetone was evaporated in vacuum. Ammonia (150 mL) was added. The mixture was filtered over Celite and the filtrate acidified with concentrated HCl. The product was extracted with diethyl ether (3*150 mL). The combined organic phases were dried (Na₂SO₄) and concentrated in vacuum to obtain 16.0 g of the acid, 3-bromo-5-methylbenzoic acid, as white crystals (yield: 60%). ¹H NMR (400 MHz, CDCl₃) δ 8.05 (s, 1H), 7.85-7.84 (m, 1H), 7.58 (s, 1H), 2.40 (s, 3H).

References:

Glaxo Group Limited US2009/203657, 2009, A1 Location in patent:Page/Page column 53