Reacción #82256

Ecuación de reacción

hydrochloric acid

ethanol

potassium hydroxide

3-(5-bromobenzo[b]thien-2-yl)-2-ethoxycarbonyl-2-(4-methoxyphenyl)propionate

→

ethyl 3-(5-bromobenzo[b]thien-2-yl)-2-(4-methoxyphenyl)propionate

Rendimiento 91.1%

Disolventes

water

Condiciones de reacción

Tratamiento posterior

1. 1
   Otroobtained in the above step a), and the thus prepared mixture
2. 2
   OtroThe resulting reaction solution
3. 3
   workup.ADDITIONwas poured
4. 4
   Otroto collect
5. 5
   Otroprecipitated crystals
6. 6
   Filtraciónby filtration
7. 7
   workup.DISSOLUTIONThe thus collected crystals were dissolved in ethyl acetate
8. 8
   Otrodried
9. 9
   workup.DISTILLATIONAfter distilling off the solvent
10. 10
    workup.DISSOLUTIONthe resulting residue was dissolved in 200 ml of ethanol
11. 11
    workup.ADDITIONmixed With 3 ml of concentrated sulfuric acid
12. 12
    Temperaturarefluxed
13. 13
    Temperaturaunder heating for 2 hours
14. 14
    TemperaturaAfter cooling
15. 15
    Otrothe resulting reaction solution
16. 16
    Concentraciónwas concentrated
17. 17
    workup.ADDITIONmixed with chloroform
18. 18
    Lavadowashed with water
19. 19
    Otrodried
20. 20
    workup.DISTILLATIONAfter distilling off the solvent
21. 21
    Otrothe resulting residue was purified

Procedimiento

A solution of 7.3 g of potassium hydroxide dissolved in 20 ml of water was added to 200 ml of an ethanol solution containing 24.2 g of 3-(5-bromobenzo[b]thien-2-yl)-2-ethoxycarbonyl-2-(4-methoxyphenyl)propionate obtained in the above step a), and the thus prepared mixture was stirred for 4 days. The resulting reaction solution was poured into cooled dilute hydrochloric acid to collect precipitated crystals by filtration. The thus collected crystals were dissolved in ethyl acetate, and then dried. After distilling off the solvent, the resulting residue was dissolved in 200 ml of ethanol, mixed With 3 ml of concentrated sulfuric acid, and then refluxed under heating for 2 hours. After cooling, the resulting reaction solution was concentrated, mixed with chloroform, washed with water, and then dried. After distilling off the solvent, the resulting residue was purified by subjecting it to silica gel column chromatography using chloroform as an eluant, thereby obtaining 20 g of ethyl 3-(5-bromobenzo[b]thien-2-yl)-2-(4-methoxyphenyl)propionate.

Fuente