Reaktion #81449

Reaktionsgleichung

1,2-dibromoethane

trimethylsilyl chloride

6-bromo-3-methyloxazolo[4,5-b]pyridin-2(3H)-one

benzyl bromide

→

3-methyl-6-benzyloxazolo[4,5-b]pyridin-2(3H)-one

Lösungsmittel

tetrahydrofuran

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturto cool until the temperature
2. 2
   Sonstigeis 35° C.
3. 3
   Temperaturis maintained for 30 minutes
4. 4
   TemperaturHeat at 50° C. for 20 minutes
5. 5
   TemperaturAfter the solution has been cooled
6. 6
   Sonstigethe zinc is removed by filtration
7. 7
   workup.ADDITIONa 10% aqueous hydrochloric acid solution is added until the aqueous phase
8. 8
   ExtraktionExtraction
9. 9
   TrocknenThe organic phase is dried over magnesium sulfate
10. 10
    Filtrationfiltered
11. 11
    Sonstigethe solvent is evaporated off under reduced pressure
12. 12
    SonstigeThe title product is purified by chromatography on silica gel (eluant: dichloromethane)
13. 13
    SonstigeThe yield obtained

Vorschrift

Zinc (227 mg, 3.48 mmol) is suspended in tetrahydrofuran (10 ml) and 1,2-dibromoethane (0.22 ml, 0.2 mmol) is added. The mixture is heated at 60° C. for 3 minutes, the solution is allowed to cool until the temperature is 35° C., and trimethylsilyl chloride (0.06 ml, 0.5 mmol) is slowly added. Stirring is maintained for 30 minutes and then benzyl bromide (0.11 ml, 0.9 mmol) is added. Wait a further 30 minutes before introducing 6-bromo-3-methyloxazolo[4,5-b]pyridin-2(3H)-one (200 mg, 0.87 mmol) and tetrakis(triphenylphosphine)palladium (4 mg). Heat at 50° C. for 20 minutes. After the solution has been cooled, the zinc is removed by filtration, the flitrate is taken up in water, and then a 10% aqueous hydrochloric acid solution is added until the aqueous phase becomes clear. Extraction is carried out with dichloromethane. The organic phase is dried over magnesium sulfate and filtered, and then the solvent is evaporated off under reduced pressure. The title product is purified by chromatography on silica gel (eluant: dichloromethane). The yield obtained is 91%. ##STR51##

Quelle