Reaktion #157454

Reaktionsgleichung

3,4-difluorophenyl propionic acid

oxalyl chloride

AlCl3

→

title compound

5,6-difluoro-2,3-dihydro-1H-inden-1-one

Lösungsmittel

CH2Cl2

Reaktionsbedingungen

Aufarbeitung

1. 1
   Einengenconcentrated in vacuo (chased 1×PhMe, ca. 100 mL)
2. 2
   workup.DISSOLUTIONThe residue was dissolved in CS2 (300 mL)
3. 3
   workup.STIRRINGThe mixture was stirred 30 min at 0° C.
4. 4
   Temperaturheated
5. 5
   Temperaturunder reflux for 4 hr
6. 6
   TemperaturUpon cooling to room temperature the solution
7. 7
   workup.ADDITIONwas carefully poured
8. 8
   Sonstigeonto crushed ice
9. 9
   Sonstigethe carbon disulfide layer was separated
10. 10
    Extraktionthe aqueous layer extracted with EtOAc
11. 11
    TrocknenCombined organics were dried over MgSO4
12. 12
    Einengenthe concentrated in vacuo
13. 13
    SonstigeThe residue was purified by flash chromatography (EtOAc/hexanes)

Vorschrift

To a solution of 3,4-difluorophenyl propionic acid (30.45 g; 163.6 mmol) and 2 drops of DMF in CH2Cl2 (200 mL) was added oxalyl chloride (41.4 g, 327 mmol) over 20 min. The resulting solution was stirred for 24 hr and concentrated in vacuo (chased 1×PhMe, ca. 100 mL). The residue was dissolved in CS2 (300 mL), cooled to 0° C. and AlCl3 (76.4 g, 573 mmol) was added over 10 min. The mixture was stirred 30 min at 0° C., then heated under reflux for 4 hr. Upon cooling to room temperature the solution was carefully poured onto crushed ice, the carbon disulfide layer was separated and the aqueous layer extracted with EtOAc. Combined organics were dried over MgSO4 and the concentrated in vacuo. The residue was purified by flash chromatography (EtOAc/hexanes), affording the title compound as a white solid. 1H NMR (400 MHz, CDCl3) δ 7.50 (t, 1H, J=8.0 Hz), 7.24 (t, 1H, J=6.6 Hz), 3.09 (t, 2H, J=5.5 Hz), 2.72-2.69 (m, 2H).

Quelle