Reaktion #1162841

ord-137b0c3d92f746d0a5784916ebbb2c8c

Reaktionsbedingungen

Detaillierte Bedingungen
See reaction.notes.procedure_details.

Aufarbeitung

  1. 1
    workup.STIRRINGstirred at 20° C. for 30 minutes
  2. 2
    EinengenThe mixture is concentrated to 25% volume by evaporation under reduced pressure
  3. 3
    workup.ADDITIONtreated with saturated aqueous ammonium chloride solution (300 mL)
  4. 4
    Extraktionextracted with ethyl acetate (2×200 mL)
  5. 5
    TrocknenThe combined extracts are dried (Na2SO4)
  6. 6
    Filtrationfiltered
  7. 7
    Sonstigethe solvent is evaporated off under reduced pressure
  8. 8
    Sonstigeto yield the crude product which
  9. 9
    Sonstigeis purified by column chromatography (silica gel, 10% acetone in hexane)

Vorschrift

N-Bromosuccinimide (3.65 g, 20.5 mmol) is added to a stirred solution of Intermediate 1a (6.80 g, 19.1 mmol) in dimethylsulphoxide (70 mL) and water (0.89 g, 0.50 mmol) at 15° C. The mixture is stirred for 2 hours and then treated with a solution of sodium hydroxide (4.0 g, 100 mmol) in dioxan-water and stirred at 20° C. for 30 minutes. The mixture is concentrated to 25% volume by evaporation under reduced pressure, treated with saturated aqueous ammonium chloride solution (300 mL) and extracted with ethyl acetate (2×200 mL). The combined extracts are dried (Na2SO4), filtered and the solvent is evaporated off under reduced pressure to yield the crude product which is purified by column chromatography (silica gel, 10% acetone in hexane) to give the title compound as a yellow oil, having the following physical characteristics:

Quelle

DOI: 10.6084/m9.figshare.5104873.v1Patent: US05905156uspto-grants-1999_05