Iodine → 3-Bromo-1,3,4,5-tetrahydro-2H-1-benzazepin-2-one

HRID 2418766Notes

Reaction equation

HRID 2418766 reaction equation
[NH:1]1[C:7]2[CH:8]=[CH:9][CH:10]=[CH:11][C:6]=2[CH2:5][CH2:4][CH2:3][C:2]1=[O:12].P(Cl)(Cl)(Cl)(Cl)Cl.II.[Br:21]Br>C(Cl)(Cl)Cl>[Br:21][CH:3]1[CH2:4][CH2:5][C:6]2[CH:11]=[CH:10][CH:9]=[CH:8][C:7]=2[NH:1][C:2]1=[O:12]

Participants

6

Reactant 4

HCID 807IodineHCID 24408BromineHCID 24819Phosphorus pentachlorideHCID 2485801,3,4,5-Tetrahydro-2H-1-benzazepin-2-one

Product 1

HCID 27571843-Bromo-1,3,4,5-tetrahydro-2H-1-benzazepin-2-one

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent

Procedure

To a solution of 2,3,4,5-tetrahydro-1H-[1]benzazepin-2-one (2.5 g) in chloroform (30 ml), phosphorus pentachloride (3.2 g) was added in portions, while maintaining the temperature at 0°-5°. When the addition was complete, iodine (30 mg) was added followed by bromine (2.5 g), which was added dropwise over 5 minutes. The mixture was then refluxed for 4 hours. The chloroform solution was evaporated and the residue was partitioned between ice-water (30 ml) and dichloromethane (75 ml). The organic phase was dried over magnesium sulfate and evaporated under reduced pressure. The crude residue was purified by chromatography over silica gel, eluting with ether and hexane (7:3). Concentration of the appropriate fractions yielded 3-bromo-2,3,4,5-tetrahydro-1H-[1]-benzazepin-2-one, m.p. 146°-148°.

Workup

  1. temperaturewhile maintaining the temperature at 0°-5°
  2. additionWhen the addition
  3. additionwas added dropwise over 5 minutes
  4. temperatureThe mixture was then refluxed for 4 hours
  5. customThe chloroform solution was evaporated
  6. customthe residue was partitioned between ice-water (30 ml) and dichloromethane (75 ml)
  7. dry with materialThe organic phase was dried over magnesium sulfate
  8. customevaporated under reduced pressure
  9. customThe crude residue was purified by chromatography over silica gel
  10. washeluting with ether and hexane (7:3)

Sources & evidence

ORD record
ord-d5b9adf806e2418b9962e1e4eed6603e
Source dataset
uspto-grants-1984_09
Patent number
US04473575

Reaction notes

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