Trifluoroacetic anhydride → 6-ethyl-1H-indole

HRID 2215824Notes

Reaction equation

HRID 2215824 reaction equation
FC(F)(F)C(OC(=O)C(F)(F)F)=O.C(O[CH:17](OCC)[CH2:18][NH:19][C:20]1[CH:25]=[CH:24][CH:23]=[C:22]([CH2:26][CH3:27])[CH:21]=1)C>FC(F)(F)C(O)=O>[CH2:26]([C:22]1[CH:21]=[C:20]2[C:25]([CH:17]=[CH:18][NH:19]2)=[CH:24][CH:23]=1)[CH3:27]

Participants

4

Reactant 2

HCID 9845Trifluoroacetic anhydrideHCID 21949966(2,2-Diethoxyethyl)-(3-ethylphenyl)amine

Product 1

HCID 183302676-ethyl-1H-indoleYield 23%

Reagents, catalysts & solvents 1

HCID 6422Trifluoroacetic acidSolvent2×

Procedure

To a solution of trifluoroacetic anhydride (45 mL) in trifluoroacetic acid (45 mL) at 4° C. under N2 was added (2,2-diethoxyethyl)-(3-ethylphenyl)amine (11.47 g, 48.36 mmol). After stirring for 30 min, the cold mixture was diluted with trifluoroacetic acid (60 mL). The mixture was stirred at reflux for 2.5 d, concentrated and extracted with methylene chloride (3×100 mL). The combined organic layers were washed with saturated NaHCO3 (3×60 mL), saturated NaCl (60 mL), dried (MgSO4) and concentrated. Flash chromatography (SiO2, 25% EtOAc/hexanes) gave the title compound (1.6 g, 23%) as a brown crystalline solid. 1H NMR (CDCl3) δ 8.03 (bs, 1H), 7.57 (m, 1H), 7.18 (s, 1H), 7.12 (m, 1H), 6.68 (m, 1H), 6.46 (m, 1H), 2.73 (m, 2H), 1.26 (m, 3H)

Workup

  1. stirringThe mixture was stirred
  2. temperatureat reflux for 2.5 d
  3. concentrationconcentrated
  4. extractionextracted with methylene chloride (3×100 mL)
  5. washThe combined organic layers were washed with saturated NaHCO3 (3×60 mL), saturated NaCl (60 mL)
  6. dry with materialdried (MgSO4)
  7. concentrationconcentrated

Sources & evidence

ORD record
ord-140bd818cda14873b56a6f784d8589ae
Source dataset
uspto-grants-2006_09
Patent number
US07109229B2

Reaction notes

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