Sodium Hydroxide → 6-methyl-2,3-dihydro-1H-indole

HRID 1475299Notes

Reaction equation

HRID 1475299 reaction equation
[CH3:1][C:2]1[CH:10]=[C:9]2[C:5]([CH:6]=[CH:7][NH:8]2)=[CH:4][CH:3]=1.C([BH3-])#N.[Na+].[OH-].[Na+]>C(O)(=O)C.O>[CH3:1][C:2]1[CH:10]=[C:9]2[C:5]([CH2:6][CH2:7][NH:8]2)=[CH:4][CH:3]=1

Participants

6

Reactant 3

HCID 14798Sodium HydroxideHCID 1379281H-Indole, 6-methyl-HCID 5003444Sodium cyanoborohydride

Product 1

HCID 122033306-methyl-2,3-dihydro-1H-indoleYield 51%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 962WaterSolvent

Conditions

Temperature
0 °C

Procedure

6-Methyl indole (0.50 g, 3.8 mmol) was dissolved in glacial acetic acid (19.1 mL) and cooled to 0° C. Sodium cyanoborohydride (0.48 g, 7.6 mmol) was added portionwise and the mixture warmed to ambient temperature and stirred for 2 h. The reaction was diluted with water (8.0 mL), made alkaline with 40% aqueous NaOH and extracted with EtOAc (3×10 mL). The combined organic extracts were washed with brine (3×30 mL), dried over sodium sulfate, filtered and concentrated. Purification by column chromatography on silica gel (gradient elution, 0-100% EtOAc/petrol), gave the title compound (0.256 g, 51%) as a purple oil. 1H NMR (Me-d3-OD): 6.96 (1H, d), 6.53 (2H, d), 3.44 (2H, t), 2.94 (2H, t), 2.23 (3H, s).

Workup

  1. temperaturethe mixture warmed to ambient temperature
  2. extractionextracted with EtOAc (3×10 mL)
  3. washThe combined organic extracts were washed with brine (3×30 mL)
  4. dry with materialdried over sodium sulfate
  5. filtrationfiltered
  6. concentrationconcentrated
  7. customPurification by column chromatography on silica gel (gradient elution, 0-100% EtOAc/petrol)

Sources & evidence

ORD record
ord-5911b77369dd4269b2134a1e8cd5d3a5
Source dataset
uspto-grants-2015_04
Patent number
US09018214B2

Reaction notes

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