Reacción #7729

Ecuación de reacción

water

N-bromosuccinimide

triphenylphosphine

ethyl [(4-hydroxy-2-pyrimidinyl)thio]acetate

→

Ethyl [(4-bromo-2-pyrimidinyl)thio]acetate

Disolventes

dioxane

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturawith cooling
2. 2
   Temperaturathe mixture is heated
3. 3
   Temperaturaat reflux for 45 min
4. 4
   Extracciónis then extracted 3× with in each case 300 ml of methyl tert-butyl ketone
5. 5
   LavadoThe organic phase is washed 2× with water and 1× with concentrated NaCl solution
6. 6
   Secadodried over magnesium sulphate
7. 7
   Concentraciónconcentrated
8. 8
   workup.STIRRINGThe residue is stirred in 60 ml of methyl tert-butyl ketone
9. 9
   Filtraciónfiltered off
10. 10
    ConcentraciónThe mother liquor is concentrated
11. 11
    Otrothe residue is purified by silica gel chromatography (dichloromethane)

Procedimiento

Under argon, 52.5 g (0.20 mol) of triphenylphosphine are initially charged in 600 ml of dioxane, and 35.6 g (0.20 mol) of N-bromosuccinimide are added a little at a time, with cooling. The mixture is stirred at RT for 30 min. 8.6 g (0.04 mol) of ethyl [(4-hydroxy-2-pyrimidinyl)thio]acetate are then added and the mixture is heated at reflux for 45 min. A total of 2 l of water are added to the mixture, which is then extracted 3× with in each case 300 ml of methyl tert-butyl ketone. The organic phase is washed 2× with water and 1× with concentrated NaCl solution, dried over magnesium sulphate and concentrated. The residue is stirred in 60 ml of methyl tert-butyl ketone and filtered off. The mother liquor is concentrated and the residue is purified by silica gel chromatography (dichloromethane).

Fuente