Phosphorus oxybromide → 3-(2,4-Dichlorophenyl)-2,5-dimethylpyrazine

HRID 1824061Notes

Reaction equation

HRID 1824061 reaction equation
P(Br)(Br)([Br:3])=O.[Cl:6][C:7]1[CH:12]=[C:11]([Cl:13])[CH:10]=[CH:9][C:8]=1[C:14]1[C:15]([CH3:22])=[N+:16]([O-])[CH:17]=[C:18]([CH3:20])[N:19]=1.CN(C1C2C(N(C)C)=CC=CC=2C=CC=1)C>C(Cl)Cl>[Br:3][C:17]1[C:18]([CH3:20])=[N:19][C:14]([C:8]2[CH:9]=[CH:10][C:11]([Cl:13])=[CH:12][C:7]=2[Cl:6])=[C:15]([CH3:22])[N:16]=1.[Cl:6][C:7]1[CH:12]=[C:11]([Cl:13])[CH:10]=[CH:9][C:8]=1[C:14]1[C:15]([CH3:22])=[N:16][CH:17]=[C:18]([CH3:20])[N:19]=1

Participants

6

Reactant 3

HCID 24613Phosphorus oxybromideHCID 88675Proton spongeHCID 221472913-(2,4-Dichlorophenyl)-2,5-dimethylpyrazine 1-oxide

Product 2

HCID 221473513-(2,4-Dichlorophenyl)-2,5-dimethylpyrazineYield 38%HCID 221474252-Bromo-5-(2,4-dichlorophenyl)-3,6-dimethylpyrazineYield 35%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

POBr3 (573 mg) was added to the solution of 3-(2,4-dichlorophenyl)-2,5-dimethylpyrazine 1-oxide (270 mg) and proton sponge (197 mg) in CH2Cl2 at 0° C. The reaction mixture was warmed to r.t. for 10 h. The reaction mixture was washed with 1N HCl, NaHCO3 and brine, dried (MgSO4), filtered and concentrated. Flash chromatography (silica gel Heptane:EtOAC 100:1) gave the title compound (110 mg, 35%) and 3-(2,4-dichlorophenyl)-2,5-dimethylpyrazine (100 mg, 38%). 1H NMR (CDCl3) δ 2.40, 2.71, 7.28, 7.40, 7.54; MS (ESI+) for C12H9Cl2N2Br1 m/z 333.0 (M+H)+.

Workup

  1. washThe reaction mixture was washed with 1N HCl, NaHCO3 and brine
  2. dry with materialdried (MgSO4)
  3. filtrationfiltered
  4. concentrationconcentrated

Sources & evidence

ORD record
ord-d5fafed2d75d4a4994e708e52bcea263
Source dataset
uspto-grants-2006_05
Patent number
US07041672B2

Reaction notes

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