1,5-Dibromopentane → N-(5-Bromopentyl)phthalimide

HRID 378645Notes

Reaction equation

HRID 378645 reaction equation
[C:1]1(=[O:11])[NH:5][C:4](=[O:6])[C:3]2=[CH:7][CH:8]=[CH:9][CH:10]=[C:2]12.[K].[Br:13][CH2:14][CH2:15][CH2:16][CH2:17][CH2:18]Br>CC(C)=O>[Br:13][CH2:14][CH2:15][CH2:16][CH2:17][CH2:18][N:5]1[C:1](=[O:11])[C:2]2=[CH:10][CH:9]=[CH:8][CH:7]=[C:3]2[C:4]1=[O:6]

Participants

4

Reactant 2

HCID 81001,5-DibromopentaneHCID 24194345Phthalimide potassium salt

Product 1

HCID 136770N-(5-Bromopentyl)phthalimide

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent

Procedure

Potassium phthalimide (92.5 g) was added in six portions over 4 hours to a boiling solution of 1,5-dibromopentane (230 g) in acetone (670 ml). The mixture was boiled under reflux for 24 hours, then cooled and filtered. The filtrate was evaporated to dryness and the residue dissolved in petroleum ether, b.p. 60-80° C. ethyl acetate (1:1) and the solution filtered. The filtrate was evaporated to dryness and the residue washed with several portions of petroleum ether, b.p. 60-80° C. to remove excess dibromopentane. The remaining oil was dried under vacuum at 50° C. The petrol washings were evaporated to dryness and distilled under vacuum to give recovered dibromopentane and a second fraction b.p. 86-120° C. at 17 mbar. This fraction solidified on cooling and scratching. A little of this solid was used to seed the remaining oil and the combined solids were recrystallised from absolute ethanol (300 ml) to give N-(5-bromopentyl)phthalimide, m.p. 62-63° C.

Workup

  1. temperatureunder reflux for 24 hours
  2. temperaturecooled
  3. filtrationfiltered
  4. customThe filtrate was evaporated to dryness
  5. dissolutionthe residue dissolved in petroleum ether
  6. filtrationb.p. 60-80° C. ethyl acetate (1:1) and the solution filtered
  7. customThe filtrate was evaporated to dryness
  8. washthe residue washed with several portions of petroleum ether, b.p. 60-80° C.
  9. customto remove excess dibromopentane
  10. customThe remaining oil was dried under vacuum at 50° C
  11. customThe petrol washings were evaporated to dryness
  12. distillationdistilled under vacuum
  13. customto give
  14. customrecovered dibromopentane
  15. temperatureon cooling
  16. customthe combined solids were recrystallised from absolute ethanol (300 ml)

Sources & evidence

ORD record
ord-0970550938b14adda3d64720c2e5751e
Source dataset
uspto-grants-2000_02
Patent number
US06031109

Reaction notes

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