ChemicalBook CAS DataBase List 3-Bromo-2,4-dimethyl-phenol

3-Bromo-2,4-dimethyl-phenol synthesis

5synthesis methods

Product Name:3-Bromo-2,4-dimethyl-phenol
CAS Number:74571-81-6
Molecular formula:C8H9BrO
Molecular Weight:201.06

66314-77-0 Synthesis

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Yield:74571-81-6 37%

Reaction Conditions:

with sulfuric acid;NaNO₂ in lithium hydroxide monohydrate at 0 - 100; for 1.5 h;

Steps:

78.3 Step 3: 3-Bromo-2,4-dimethyl-phenol

3-Bromo-2,4-dimethyl-phenylamine (48.41 g, 242 mmol) was dispersed in 1.0 M aqueous sulfuric acid (363 mL) and cooled to 0 °C. Solution of sodium nitrite (25.05 g, 363 mmol) in water (55 mL) was added dropwise and the reaction mixture was stirred for 30 minutes at 0 °C.96.2% sulfuric acid (125 mL) was added slowly and the reaction mixture was heated to 100 °C for 1 hour. After cooling to room temperature, the reaction mixture was poured into iced water (1200 mL) and the product extracted with ethyl acetate (3 x 200 mL). The combined organic layers were washed with brine, dried over anhydrous sodium sulfate and concentrated. The obtained crude was purified by vacuum distillation (b.p.92 °C/2 torr) followed by recrystallization from hexanes at -20 °C to afford 3-bromo-2,4-dimethyl-phenol (17.96 g, 37%) as a yellow solid.¹H NMR (250 MHz, CDCl₃) δ (ppm): 6.96 (d, J = 8.0 Hz, 1H), 6.65 (d, J = 8.0 Hz, 1H), 4.79 (s, 1H), 2.36 (s, 3H), 2.34 (s, 3H).

References:

WO2022/76627,2022,A1 Location in patent:Paragraph 00324; 00326