Maleimide → 1,2,3,4-Tetrahydrocarbazole

HRID 1020909Notes

Reaction equation

HRID 1020909 reaction equation
[CH3:1]N(C)C1C=CN=C2C=1C=CN2.[C:13]1([C:18]2[NH:29][C:21]3=N[CH:23]=[CH:24][C:25](N(C)C)=[C:20]3[CH:19]=2)[CH2:17][CH2:16][CH2:15]C=1.C1(=O)NC(=O)C=C1.[Br-].[Yb+3].[Br-].[Br-]>C1(C)C=CC=CC=1>[CH2:1]1[C:21]2[NH:29][C:18]3[C:19](=[CH:15][CH:16]=[CH:17][CH:13]=3)[C:20]=2[CH2:25][CH2:24][CH2:23]1

Participants

6

Reactant 4

HCID 10935MaleimideHCID 21811693HCID 21811693, compoundHCID 2521232513759-89-2HCID 67273450HCID 67273450, compound

Product 1

HCID 136641,2,3,4-TetrahydrocarbazoleYield 88%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

This compound was prepared using the same general procedure as outlined for la starting with 4-dimethylamino-7-azaindole. To a 25 mL round-bottomed flask containing a magnetic stirring bar equipped with a reflux condenser and a three-way stopcock connected to an argon balloon was charged with (2-cyclopent-1-enyl-1H-pyrrolo[2,3-b]pyridine-4-yl)-dimethylamine (12 mg, 0.05 mmol) followed by toluene (2 mL), maleimide (157 mg, 0.79 mmol) and ytterbium(III) bromide (19 mg, 0.04 mmol). The reaction mixture was refluxed for 1 h and the toluene evaporated under vacuum. The crude material was triturated with methanol (10 mL) filtered and washed with methanol. The filtrate was concentrated and purified by silica gel column chromatography to obtain tetrahydrocarbazole (15 mg, 88% yield). An oven dried, 25 mL round-bottomed flask containing a magnetic stirring bar was charged with 7-dimethylamino-1,2,3,3a,3b,6a,11,11b-octahydro-5,10,11-triaza-benzo[a]trindene-4,6-dione (15 mg, 0.04 mmol) followed by acetonitrile (4 mL). DDQ (35 mg, 0.15 mmol) was added at 15° C. and then stirred at rt for 1 h and at reflux for 6 h. Acetonitrile was evaporated under vacuum and dissolved in ethyl acetate then washed with saturated sodium bicarbonate, brine, dried (MgSO4) and concentrated to give a crude material. The crude material was purified by silica gel column chromatography to give Sac (2.3 mg, 15% yield). MS (m/z): 321 (M+1).

Workup

  1. customThis compound was prepared
  2. additionTo a 25 mL round-bottomed flask containing a magnetic stirring bar
  3. customequipped with a reflux condenser
  4. temperatureThe reaction mixture was refluxed for 1 h
  5. customthe toluene evaporated under vacuum
  6. customThe crude material was triturated with methanol (10 mL)
  7. filtrationfiltered
  8. washwashed with methanol
  9. concentrationThe filtrate was concentrated
  10. custompurified by silica gel column chromatography

Sources & evidence

ORD record
ord-946f2f5b839e421b855679375b8cb226
Source dataset
uspto-grants-2014_05
Patent number
US08716493B2

Reaction notes

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