Ammonium Chloride → 1,3-Dihydro-2H-pyrrolo(2,3-b)pyridin-2-one

HRID 2415085Notes

Reaction equation

HRID 2415085 reaction equation
Br[C:2]1(Br)[C:10]2[C:5](=[N:6][CH:7]=[CH:8][CH:9]=2)[NH:4][C:3]1=[O:11].[NH4+].[Cl-]>C1COCC1.[Zn]>[NH:4]1[C:5]2[C:10](=[CH:9][CH:8]=[CH:7][N:6]=2)[CH2:2][C:3]1=[O:11]

Participants

5

Reactant 2

HCID 25517Ammonium ChlorideHCID 138640943,3-Dibromo-1H-pyrrolo[2,3-b]pyridin-2(3H)-one

Product 1

HCID 138640951,3-Dihydro-2H-pyrrolo(2,3-b)pyridin-2-one

Reagents, catalysts & solvents 2

HCID 23994ZincCatalystHCID 8028TetrahydrofuranSolvent

Procedure

A solution of 3,3-dibromo-7-azaoxindole (2.0 g, 7.2 mmol) in THF (50 mL) is stirred at room temperature and a saturated aqueous solution of NH4Cl is added. Activated zinc powder is added and the reaction mixture is stirred for 2 h. The zinc is removed by filtration through a pad of diatomaceous earth and the organic layer is separated. The aqueous layer is extracted with THF (10 mL) and the combined organic layers are dried over anhydrous MgSO4, filtered and evaporated. The residue is slurried in 10:1 CHCl3:MeOH (15 mL) and filtered through a pad of silica gel and the filtrate is evaporated. The residue is triturated with water and the solid is collected by filtration and dried under vacuum to give 7-azaoxindole, 0.668g (70%). 1H NMR (DMSO-d6) δ10.94 (s, 1H), 8.02 (d, 1H, J=5.2 Hz), 7.52 (d, 1H, J=6.8 Hz), 6.90 (dd, 1H, J=6.8, 5.2 Hz), 3.53 (s, 2H). MS(AP−ve) 133 (100) (M−H)

Workup

  1. customThe zinc is removed by filtration through a pad of diatomaceous earth
  2. customthe organic layer is separated
  3. extractionThe aqueous layer is extracted with THF (10 mL)
  4. dry with materialthe combined organic layers are dried over anhydrous MgSO4
  5. filtrationfiltered
  6. customevaporated
  7. filtrationMeOH (15 mL) and filtered through a pad of silica gel
  8. customthe filtrate is evaporated
  9. customThe residue is triturated with water
  10. filtrationthe solid is collected by filtration
  11. customdried under vacuum

Sources & evidence

ORD record
ord-259bf176c4e44accb62124b242027432
Source dataset
uspto-grants-2004_11
Patent number
US06818632B2

Reaction notes

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