Reacción #463570

Ecuación de reacción

6-hydroxy-chromene-2-one

water

1,2-dibromoethane

potassium carbonate

→

product

Rendimiento 26.0%

6-(2-Bromo-ethoxy)-chromen-2-one

Rendimiento 26.0%

Disolventes

ethyl acetate

acetone

Condiciones de reacción

Tratamiento posterior

1. 1
   Otrocan be synthesized in accordance with the procedure
2. 2
   Temperaturaat reflux for 48 hours
3. 3
   OtroThe cooled reaction mixture
4. 4
   FiltraciónThe mixture is filtered
5. 5
   Lavadothe insoluble material is washed with a small amount of additional ethyl acetate
6. 6
   OtroThe combined filtrates are separated
7. 7
   Lavadothe aqueous layer is washed several times with fresh ethyl acetate
8. 8
   LavadoThe combined organic layers are washed with 5% aqueous sodium carbonate solution and brine
9. 9
   Secadodried (sodium sulfate)
10. 10
    Otroevaporated
11. 11
    OtroThe residue is purified by flash chromatography (1% methanol in dichloromethane elution)

Procedimiento

A mixture of 6-hydroxy-chromene-2-one, which can be synthesized in accordance with the procedure set forth by T. Harayama, K. Katsuno, H. Nishioka, M. Fujii, Y. Nishita, H. Ishii, and Y. Kaneko, Heterocycles, 1994;39:613, (3.2 g, 19.7 mmol), 1,2-dibromoethane (6.7 mL, 14.6 g, 78 mmol), and potassium carbonate (5.4 g, 39 mmol) in 150 mL of acetone is stirred at reflux for 48 hours. The cooled reaction mixture is added to 1.0 L of water and 250 mL of ethyl acetate. The mixture is filtered, and the insoluble material is washed with a small amount of additional ethyl acetate. The combined filtrates are separated, and the aqueous layer is washed several times with fresh ethyl acetate. The combined organic layers are washed with 5% aqueous sodium carbonate solution and brine, then dried (sodium sulfate), and evaporated. The residue is purified by flash chromatography (1% methanol in dichloromethane elution) to give 1.4 g (26%) of product. A sample recrystallized from ethyl acetate-hexane had melting point (mp) 101-102° C.

Fuente