Hydrochloric Acid → 4,6-Dichloro-1H-indole

HRID 2379113Notes

Reaction equation

HRID 2379113 reaction equation
[Cl:1][C:2]1[CH:10]=[C:9]([Cl:11])[CH:8]=[C:7]2[C:3]=1[CH:4]=[C:5](C(O)=O)[NH:6]2.Cl>N1C2C(=CC=CC=2)C=CC=1.[Cu]>[Cl:1][C:2]1[CH:10]=[C:9]([Cl:11])[CH:8]=[C:7]2[C:3]=1[CH:4]=[CH:5][NH:6]2

Participants

5

Reactant 2

HCID 313Hydrochloric AcidHCID 1279884,6-Dichloro-1H-indole-2-carboxylic acid

Product 1

HCID 144196244,6-Dichloro-1H-indoleYield 93.9%

Reagents, catalysts & solvents 2

HCID 23978CopperCatalystHCID 7047QuinolineSolvent

Procedure

Dissolve 4,6-dichloro-indole-2-carboxylic acid (1.0g, 4.35mmol) in quinoline (25mL). Add copper powder (100mg) and heat to 220° C. for 3 hours. Pour the resulting black solution into cold concentrated hydrochloric acid (300mL) and extract into ethyl ether (500mL). Filter, wash with 1M hydrochloric acid (2×200mL), water (100mL) and dry (MgSO4). Evaporate the solvent in vacuo to give a brown oil (0.76g). Purify by silica gel chromatography (17% ethyl acetate/hexane) to give the title compound as an amber oil (0.66g, 81%). 1H NMR (CDCl3 /TMS): 6.56-6.59 ppm (1H, m), 7.10-7.13 ppm (2H, m), 7.16-7.18 ppm (1H, m). 13C NMR (CDCl3), ppm: 101.48, 110.16, 120.24, 125.77, 125.94, 126.54, 122.79, 106.54.

Workup

  1. extractionextract into ethyl ether (500mL)
  2. filtrationFilter
  3. washwash with 1M hydrochloric acid (2×200mL), water (100mL)
  4. dry with materialdry (MgSO4)
  5. customEvaporate the solvent in vacuo

Sources & evidence

ORD record
ord-fe2f912407e94f44bddf7f315c6a36c2
Source dataset
uspto-grants-1994_11
Patent number
US05360814

Reaction notes

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