Potassium Carbonate → Indole

HRID 1721377Notes

Reaction equation

HRID 1721377 reaction equation
C(O[C:6]([N:8]1[CH2:11][CH:10]([CH2:12][CH:13]=O)[CH2:9]1)=O)(C)(C)C.[CH3:15][C:16]1N(CC2C=CC(NN)=CC=2)C=CN=1.C([O-])([O-])=O.[K+].[K+]>OS(O)(=O)=O>[NH:8]1[C:11]2[C:10](=[CH:12][CH:13]=[CH:15][CH:16]=2)[CH:9]=[CH:6]1

Participants

5

Reactant 3

HCID 11430Potassium CarbonateHCID 103979444-(2-Methylimidazol-1-ylmethyl)phenylhydrazineHCID 53415272tert-Butyl 3-(2-oxoethyl)azetidine-1-carboxylate

Product 1

HCID 798IndoleYield 105.1%

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent

Procedure

N-tert-Butyloxycarbonyl-3-formylmethylazetidine (0.3 g, 1.51 mmol) was added to a solution of 4-(2-methylimidazol-1-ylmethyl)phenylhydrazine (0.36 g, 1.51 mmol) in 4% H2SO4 (25 ml) and the resulting solution refluxed for 3h. The mixture was then cooled to room temperature, basified with K2CO3 and extracted with n-butanol (2×100 ml). The combined extracts were dried (MgSO4), evaporated, and the residue chromatographed through silica-gel eluting with CH2Cl2 /MeOH/NH3 (20:8:1) to give the title-indole (0.186 g, 46%), mp 88°-90° C.; δ (250 MHz, CD3OD) 2.02 (3H, s, CH3), 3.76-3.86 (4H, m, 2 of CH2), 4.04-4.20 (1H, m, CH of azetidine), 5.06 (2H, s, CH2), 6.70 (1H, d, J=1.4 Hz, Ar--H), 6.82 (1H, dd, J=1.5 and 8.4 Hz, Ar--H), 6.90 (1H, d, J=1.4 Hz, Ar--H), 7.12 (1H, s, Ar--H), 7.23 (1H, d, J =8.4Hz, At-H), 7.26 (1H, d, J =1.5Hz, Ar--H).

Workup

  1. temperaturethe resulting solution refluxed for 3h
  2. extractionextracted with n-butanol (2×100 ml)
  3. dry with materialThe combined extracts were dried (MgSO4)
  4. customevaporated
  5. customthe residue chromatographed through silica-gel
  6. washeluting with CH2Cl2 /MeOH/NH3 (20:8:1)

Sources & evidence

ORD record
ord-754707cd8dee48adbbef9800c77fa92c
Source dataset
uspto-grants-1996_04
Patent number
US05510362

Reaction notes

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