Bromide ion → 5-Bromomethyl-2-(3-nitro-phenyl)-oxazolo[4,5-b]pyridine

HRID 1924046Notes

Reaction equation

HRID 1924046 reaction equation
[CH3:1][C:2]1[N:7]=[C:6]2[N:8]=[C:9]([C:11]3[CH:16]=[CH:15][CH:14]=[C:13]([N+:17]([O-:19])=[O:18])[CH:12]=3)[O:10][C:5]2=[CH:4][CH:3]=1.C1C(=O)N([Br:27])C(=O)C1.C(OOC(=O)C1C=CC=CC=1)(=O)C1C=CC=CC=1.[Br-]>C(Cl)(Cl)(Cl)Cl>[Br:27][CH2:1][C:2]1[N:7]=[C:6]2[N:8]=[C:9]([C:11]3[CH:16]=[CH:15][CH:14]=[C:13]([N+:17]([O-:19])=[O:18])[CH:12]=3)[O:10][C:5]2=[CH:4][CH:3]=1

Participants

6

Reactant 4

HCID 259Bromide ionHCID 7187Benzoyl PeroxideHCID 67184N-bromobutanimide2×HCID 596799065-Methyl-2-(3-nitro-phenyl)-oxazolo[4,5-b]pyridine

Product 1

HCID 596800675-Bromomethyl-2-(3-nitro-phenyl)-oxazolo[4,5-b]pyridine

Reagents, catalysts & solvents 1

HCID 5943Carbon TetrachlorideSolvent

Procedure

In a typical run, 400 mg of 5-methyl-2-(3-nitro-phenyl)-oxazolo[4,5-b]pyridine (1.57 mmol) was suspended in 50 mL of CCl4 along with 280 mg (1.57 mmol) of NBS and 20 mg of benzoyl peroxide. The reaction mixture was stirred under reflux for 4 hours. LC/MS showed about 50% conversion to the desired bromide. After another 2 hours of reflux, no additional change was observed. Another 1 eq of NBS was added and reflux was continued for another 4 hours. LC/MS showed complete conversion. The reaction mixture was concentrated and the resulting crude product was purified by chromatography (Isco, gradient elution, CH2Cl2 to 9:1 CH2Cl2/MeOH) to afford essentially quantitative yield of 5-bromomethyl-2-(3-nitro-phenyl)-oxazolo[4,5-b]pyridine.

Workup

  1. temperatureunder reflux for 4 hours
  2. temperatureAfter another 2 hours of reflux
  3. temperaturereflux
  4. concentrationThe reaction mixture was concentrated
  5. customthe resulting crude product was purified by chromatography (Isco, gradient elution, CH2Cl2 to 9:1 CH2Cl2/MeOH)

Sources & evidence

ORD record
ord-8dafd009b1334edba64b7c3a85703f8b
Source dataset
uspto-grants-2012_05
Patent number
US08178536B2

Reaction notes

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