Diammonium hydrogen phosphate → 5-Bromo-3-cyanoindole

HRID 2250260Notes

Reaction equation

HRID 2250260 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[NH:7][CH:6]=[C:5]2[CH:11]=O.P([O-])([O-])(O)=O.[NH4+:18].[NH4+]>[N+](CCC)([O-])=O.C(O)(=O)C>[Br:1][C:2]1[CH:3]=[C:4]2[C:8](=[CH:9][CH:10]=1)[NH:7][CH:6]=[C:5]2[C:11]#[N:18]

Participants

5

Reactant 2

HCID 24540Diammonium hydrogen phosphateHCID 701375-Bromoindole-3-carbaldehyde

Product 1

HCID 36233545-Bromo-3-cyanoindoleYield 87.2%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 79031-NitropropaneSolvent

Procedure

A mixture of 5-bromo-indole-3-carboxaldehyde (5 g, 22.3 mmol), diammonium hydrogen phosphate (15.6 g, 31.8 mmol) in 1-nitropropane (66 mL) and acetic acid (22 mL) were heated at reflux for 16 h. After cooling to room temperature, the solvents were removed under reduced pressure and water added to the dark residue. After a short while, 5-bromo-1H-indole-3-carbonitrile precipitated rapidly. The solid was filtered, washed severally with water and dried for several hours to afford 4.3 g (86%) of the desired product. 1H-NMR (CD3OD) δ 7.40 (m, 2H), 7.77 (s, 1H), 7.97 (s, 1H). Mass spec.: 222.95 (MH)+.

Workup

  1. temperaturewere heated
  2. temperatureat reflux for 16 h
  3. customthe solvents were removed under reduced pressure and water
  4. additionadded to the dark residue
  5. customAfter a short while, 5-bromo-1H-indole-3-carbonitrile precipitated rapidly
  6. filtrationThe solid was filtered
  7. washwashed severally with water
  8. customdried for several hours

Sources & evidence

ORD record
ord-e64725207560451f8062b23c26176c13
Source dataset
uspto-grants-2008_01
Patent number
US07314883B2

Reaction notes

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