ChemicalBook CAS DataBase List 3-BROMOBENZENE-1,2-DIOL

3-BROMOBENZENE-1,2-DIOL synthesis

8synthesis methods

Product Name:3-BROMOBENZENE-1,2-DIOL
CAS Number:14381-51-2
Molecular formula:C6H5BrO2
Molecular Weight:189.01

28165-49-3

14381-51-2

The general procedure for the synthesis of 3-bromocatechol from 2-bromo-6-methoxyphenol was as follows: to an anhydrous dichloromethane (40 mL) solution of 2-bromo-6-methoxyphenol (8.00 g, 39.4 mmol) was slowly added boron tribromide (1 M in dichloromethane, 43.1 mmol, 43.0 mL) at -78 °C. The reaction mixture was stirred for 1 hour at room temperature, then poured into ice water and continued to stir for 30 minutes. Subsequently, extraction was performed with dichloromethane (3 x 30 mL). The organic layers were combined, dried with anhydrous magnesium sulfate, and concentrated to give the target product 3-bromocatechol (6.90 g, 93% yield) as a brown oil. Thin layer chromatography (TLC) analysis showed an Rf value of 0.2 (unfolding agent: toluene/ethyl acetate = 9:1). The 1H NMR data of the product were as follows: δH 5.60 (1H, broad single peak, OH), 5.69 (1H, broad single peak, OH), 6.72 (1H, double peak, J=8.1 Hz), 6.87 (1H, double peak, J=1.5,8.1 Hz), 7.00 (1H, double peak, J=1.5,8.1 Hz); 13C NMR data: δC 109.5, 114.9, 121.9, 123.3, 140.3, 144.5.The 1H NMR spectra of the products were in agreement with the literature reports.

28165-49-3 Synthesis

28165-49-3
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14381-51-2
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Yield:14381-51-2 93%

Reaction Conditions:

Stage #1:6-bromoguaiacol with boron tribromide in dichloromethane at -78 - 20; for 1 h;
Stage #2: with water in dichloromethane for 0.5 h;Cooling with ice;

Steps:

4.2.17. 1-Bromo-2,3-dihydroxybenzene (3-bromocatechol)
To a cold (-78 °C) solution of 2-bromo-6-methoxyphenol (8.00 g, 39.4 mmol) in dry CH₂Cl₂ (40 mL) was added slowly BBr₃ (1 M in CH₂Cl₂, 43.1 mmol, 43.0 mL). After stirring at rt for 1 h, the mixture was poured onto ice-water, stirred for 30 min and extracted with CH₂Cl₂ (3×30 mL). The organic layer was dried (MgSO₄) then concentrated affording the title product as a brownish oil (6.90 g, 93%); R_f (toluene/EtOAc 9:1) 0.2; δ_H 5.60 (1H, br s, OH), 5.69 (1H, br s, OH), 6.72 (1H, dd, J 8.1, 8.1 Hz), 6.87 (1H, dd, J 1.5, 8.1 Hz), 7.00 (1H, dd, J 1.5, 8.1 Hz); δ_C 109.5, 114.9, 121.9, 123.3, 140.3, 144.5. ¹H NMR is in accordance with the literature data.²⁰