Piperazine → 1-(5-Bromopyridin-2-yl)piperazine

HRID 1952737Notes

Reaction equation

HRID 1952737 reaction equation
Br[C:2]1[CH:7]=[CH:6][C:5]([Br:8])=[CH:4][N:3]=1.[NH:9]1[CH2:14][CH2:13][NH:12][CH2:11][CH2:10]1>>[Br:8][C:5]1[CH:6]=[CH:7][C:2]([N:9]2[CH2:14][CH2:13][NH:12][CH2:11][CH2:10]2)=[N:3][CH:4]=1

Participants

3

Reactant 2

HCID 4837PiperazineHCID 693532,5-Dibromopyridine

Product 1

HCID 164142271-(5-Bromopyridin-2-yl)piperazine

Procedure

The pyridine intermediate was prepared by treating a suspension of 5-bromo-2-(piperazin-1-yl)pyridine (7.0 g, 28.9 mmol) with di-tert-butyldicarbonate (6.30 g, 28.9 mmol) and the resulting mixture stirred for 2 h. The solvent was removed under reduced pressure to give the desired product (8.76 g as a beige solid after recrystallisation from aqueous ethanol, m.p. 88-90°. δH (CDCl3) 8.18 (1 H, d, J 2.5 Hz), 7.52 (1H, dd, J 9.0, 2.5 Hz), 6.52 (1H, d, J 9.0 Hz), 3.50 (8H, m) and 1.47 (9H, s). The 5-bromo-2-(piperazin-1-yl)pyridine was prepared by heating a mixture of 2,5-dibromopyridine (10.0 g, 42.4 mmol) and piperazine (7.98g, 92.8 mmol) as a melt at 125° for 3 h. On cooling to room temperature the mixture was triturated with methanol-dichloromethane to afford the desired product (7.0g) as a beige solid. δH (CDCl3) 8.18 (1H, d, J 2.1 Hz), 7.25 (1H, dd, J 9.1, 2.1 Hz), 6.52 (1H, d, J 9.1 Hz), 3.47 (4H, m), 2.97 (4H, m) and 1.75 (1H br s).

Workup

  1. customafter recrystallisation from aqueous ethanol, m.p. 88-90°
  2. temperatureby heating
  3. customwas triturated with methanol-dichloromethane

Sources & evidence

ORD record
ord-f375410219604b4baab28ade92e59ef9
Source dataset
uspto-grants-2000_09
Patent number
US06114333

Reaction notes

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