Methanol → 2-methyl-1H-indol-5-ol

HRID 889893Notes

Reaction equation

HRID 889893 reaction equation
C[O:2][C:3]1[CH:4]=[C:5]2[C:9](=[CH:10][CH:11]=1)[NH:8][C:7]([CH3:12])=[CH:6]2.B(Br)(Br)Br.C(Cl)(Cl)Cl.CO>ClCCl>[NH4+:8].[OH-:2].[CH3:12][C:7]1[NH:8][C:9]2[C:5]([CH:6]=1)=[CH:4][C:3]([OH:2])=[CH:11][CH:10]=2

Participants

7

Reactant 4

HCID 887MethanolHCID 6212ChloroformHCID 25134Boron tribromideHCID 706425-Methoxy-2-methylindole

Product 2

HCID 14923Ammonium HydroxideHCID 833362-methyl-1H-indol-5-olYield 119.5%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

A solution of 5-Methoxy-2-methyl-1H-indole (2 g, 12.4 mmol) in 10 mL dichloromethane was cooled to −78° C. A 1.0 M solution of BBr3 in dichloromethane (30 mL, 30.0 mmol) was added and the resultant mixture was stirred at −78° C. for three hours. The reaction was carefully quenched into ice water and extracted with dichloromethane two times. The combined organic layers were washed with brine, dried over magnesium sulfate, and evaporated under reduced pressure to give a dark oil. Silica gel chromatography (98:1.8:0.2 CHCl3:CH3OH:NH4OH) of the residue gave a 60% yield of 2-methyl-1H-indol-5-ol (1.09 g) as a tan solid. C9H9NO: GC/MS: r.t.=2.88 min., m/z 146. 1H NMR (CD3OD): δ 7.03 (d, 1H, J=8.7 Hz), 6.77 (s, 1H), 6.53 (D, 1H, J=8.7 Hz), 5.92 (s, 1H), 2.32 (s, 3H) ppm.

Workup

  1. customThe reaction was carefully quenched into ice water
  2. extractionextracted with dichloromethane two times
  3. washThe combined organic layers were washed with brine
  4. dry with materialdried over magnesium sulfate
  5. customevaporated under reduced pressure
  6. customto give a dark oil

Sources & evidence

ORD record
ord-bab3e63b84844b1384996834bc981496
Source dataset
uspto-grants-2006_02
Patent number
US06995171B2

Reaction notes

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