Reaction #9379

Reaction equation

AlCl3

Thionyl chloride

2,3-dichloro-benzoic acid

benzene

→

6,7-dichloro-1-indanone

Yield 80.0%

Solvents

dichloroethane

Conditions

Workup

1. 1
   Temperatureto reflux until no more gas evolution
2. 2
   Concentrationwas concentrated
3. 3
   workup.ADDITIONThe concentrate was diluted with dichloroethane
4. 4
   OtherEthylene was bubbled through the mixture for 4 h
5. 5
   Otherquenched with 4 N HCl
6. 6
   OtherThe resulting layers were separated
7. 7
   Extractionthe aqueous layer was extracted with Et2O (3×250 mL)
8. 8
   WashThe combined organic extracts were washed with H2O (3×150 mL), saturated NaHCO3 (3×150 mL), brine (1×150 mL)
9. 9
   Dryingdried over MgSO4
10. 10
    Concentrationconcentrated
11. 11
    workup.ADDITIONThe concentrate was added to a slurry of AlCl3 (9.0 g) and NaCl (2.4 g) at 130° C
12. 12
    workup.STIRRINGThe resulting mixture was stirred at 180° C. for 2 hours after which it
13. 13
    Temperaturewas cooled to room temperature
14. 14
    Otherquenched with ice
15. 15
    ExtractionThe mixture was extracted with CH2Cl2 (3×500 mL)
16. 16
    Concentrationthe combined organic extracts were concentrated
17. 17
    Otherpurified by column chromatography

Procedure

Thionyl chloride (5.73 mL, ˜79 mmol) and 2,3-dichloro-benzoic acid (commercially available from Aldrich) (10.0 g, 52.4 mmol) in benzene was heated to reflux until no more gas evolution was observed. After cooling to rt the mixture was concentrated. The concentrate was diluted with dichloroethane and added to AlCl3 (7.0 g, ˜53 mmol) in dichloroethane at 10–20° C. Ethylene was bubbled through the mixture for 4 h. The mixture was stirred overnight and quenched with 4 N HCl. The resulting layers were separated and the aqueous layer was extracted with Et2O (3×250 mL). The combined organic extracts were washed with H2O (3×150 mL), saturated NaHCO3 (3×150 mL), brine (1×150 mL), dried over MgSO4 and concentrated. The concentrate was added to a slurry of AlCl3 (9.0 g) and NaCl (2.4 g) at 130° C. The resulting mixture was stirred at 180° C. for 2 hours after which it was cooled to room temperature and quenched with ice followed by concentrated HCl. The mixture was extracted with CH2Cl2 (3×500 mL) and the combined organic extracts were concentrated and purified by column chromatography using 20% EtOAc:hexane eluant to give 6.8 g (80%) of 6,7-dichloro-1-indanone. Use of 6,7-dichloro-indan-1-one in Method NINETEEN produced 4-(4,5-dichloro-indan-2-yl)-1,3-dihydro-imidazole-2-thione (Compound 153).

Source