Phosphorus oxychloride → 5-Chloro-2,3-Diphenylpyrazine

HRID 1830759Notes

Reaction equation

HRID 1830759 reaction equation
O[C:2]1[CH:7]=[N:6][C:5]([C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=2)=[C:4]([C:14]2[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=2)[N:3]=1.O=P(Cl)(Cl)[Cl:22]>C(Cl)Cl>[Cl:22][C:2]1[CH:7]=[N:6][C:5]([C:8]2[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=2)=[C:4]([C:14]2[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=2)[N:3]=1

Participants

4

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 178516746HCID 178516746, compound

Product 1

HCID 36544935-Chloro-2,3-Diphenylpyrazine

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Conditions

Temperature
100 °C

Procedure

A stirred solution of 2-Hydroxy-5,6-diphenylpyrazine (430 mg, 1.7 mmol) in 5.2 mL POCl3 in a capped reaction vial was heated to 100° C. for 4 hours. The orange solution was cooled to room temperature and stirred rapidly in a mixture of CH2Cl2 (100 mL) and ice cold 10% Na2CO3 (100 mL) for 15 minutes. The organic layer was isolated and washed 2×100 mL with 10% Na2CO3. The organics were isolated, dried (MgSO4), filtered and concentrated to the chloropyrazine, which existed as white solid (450 mg, quantitative). 1H-NMR (400 MHz, CDCl3) δ8.59 (s, 1H), 7.45-7.39 (m, 4H), 7.36-7.24 (m, 6H).

Workup

  1. temperatureThe orange solution was cooled to room temperature
  2. customThe organic layer was isolated
  3. washwashed 2×100 mL with 10% Na2CO3
  4. customThe organics were isolated
  5. dry with materialdried (MgSO4)
  6. filtrationfiltered
  7. concentrationconcentrated to the chloropyrazine, which

Sources & evidence

ORD record
ord-c79f63db48454ca6830bb4037bca4400
Source dataset
uspto-grants-2006_06
Patent number
US07067506B2

Reaction notes

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