Reaktion #347109

Reaktionsgleichung

HCl

Sodium nitrate

4-bromo-3-hydroxy-6-methoxybenzoic acid

→

title compound

4-Bromo-3-hydroxy-6-methoxy-2-nitrobenzoic acid

Lösungsmittel

water

diethyl ether

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturAfter slowly raising the temperature to room temperature the mixture
2. 2
   ExtraktionExtraction between H2O (20 mL) and CH2Cl2 (3×30 mL)
3. 3
   Sonstigedrying the organic phase
4. 4
   Filtrationwith MgSO4, filtration and evaporation under reduced pressure
5. 5
   Sonstigegave
6. 6
   workup.ADDITIONa mixture of products
7. 7
   SonstigePurification by silica gel chromatography (HOAc-EtOAc-toluene 1:2:8)

Vorschrift

Sodium nitrate (361 mg, 4.25 mmol) was dissolved in water (4 mL) and LaNO3 *6H2O (18 mg, 0.04 mmol) and HCl (12M, 4 mL) were added. The solution was cooled to 0° C. and a slurry of 4-bromo-3-hydroxy-6-methoxybenzoic acid in diethyl ether (20 mL) was added to the reaction mixture in portions during 10 min. After slowly raising the temperature to room temperature the mixture was stirred for 7 h. Extraction between H2O (20 mL) and CH2Cl2 (3×30 mL), drying the organic phase with MgSO4, filtration and evaporation under reduced pressure gave a mixture of products. Purification by silica gel chromatography (HOAc-EtOAc-toluene 1:2:8) gave the title compound (0.6 g). 1H NMR (CD3OD): δ7.57 (s, 1H), 3.85 (s, 3H). MS (EI, 70 eV): m/z (rel. int.) 291/293 (M+, 21/19).

Quelle