Reaktion #43721

Reaktionsgleichung

methyl chloroacetate

4-bromo-2-hydroxybenzaldehyde

potassium hydroxide

potassium carbonate

→

title compound

6-Bromo-1-benzofuran-2-carboxylic acid

Lösungsmittel

water

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONinitially charged
2. 2
   Temperaturcooled to 0° C.
3. 3
   SonstigeThe solvent is removed under reduced pressure
4. 4
   workup.ADDITIONThe residue is diluted with water
5. 5
   FiltrationThe product is filtered off
6. 6
   Sonstigedried under high vacuum
7. 7
   SonstigeFor fine purification
8. 8
   Sonstigethe product is purified on silica gel 60 (mobile phase: toluene→toluene/acetic acid 50:1→toluene/ethyl acetate/acetic acid 35:5:1)
9. 9
   SonstigeThe solvent is removed under reduced pressure

Vorschrift

8.0 g (39.8 mmol) of 4-bromo-2-hydroxybenzaldehyde and 1.47 g (3.98 mmol) of tetra-N-butylammonium iodide are, together with 22 g (159.19 mmol) of anhydrous potassium carbonate, initially charged. 9.07 g (83.57 mmol) of methyl chloroacetate are added. The reaction mixture is heated at 130° C. for 4 h and then cooled to 0° C. using an ice bath. 100 ml of THF and 13.4 g (238.8 mmol) of potassium hydroxide in 50 ml of water are added and the mixture is then stirred at RT overnight. The solvent is removed under reduced pressure. The residue is diluted with water and acidified with conc. hydrochloric acid. The product is filtered off and dried under high vacuum. For fine purification, the product is purified on silica gel 60 (mobile phase: toluene→toluene/acetic acid 50:1→toluene/ethyl acetate/acetic acid 35:5:1). The solvent is removed under reduced pressure. 3.8 g (40% of theory) of the title compound are isolated.

Quelle