Benzil → 2,3-Diphenylpyrido[2,3-b]pyrazine

HRID 2276586Notes

Reaction equation

HRID 2276586 reaction equation
[C:1]1([C:7]([C:9]([C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=2)=O)=O)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[N:17]1[CH:22]=[CH:21][CH:20]=[C:19]([NH2:23])[C:18]=1[NH2:24]>CO.C(O)(=O)C>[C:1]1([C:7]2[N:23]=[C:19]3[CH:20]=[CH:21][CH:22]=[N:17][C:18]3=[N:24][C:9]=2[C:11]2[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1

Participants

5

Reactant 2

HCID 8651BenzilHCID 99562,3-Diaminopyridine

Product 1

HCID 8175662,3-Diphenylpyrido[2,3-b]pyrazine

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 887MethanolSolvent

Conditions

Temperature
60 °C

Procedure

A solution of benzil (45.7 g, 217 mmol) and pyridine-2,3-diamine (23.7 g, 217 mmol) in methanol (514 ml) and acetic acid (57 ml) was heated at 160° C. for 10 mins using microwave radiation. The reaction mixture was concentrated in vacuo. To the crude residue in methanol (510 ml) was added activated charcoal (25 g) and the suspension was stirred at 60° C. for 1 h. The suspension was filtered hot, cooled and then was stirred in an ice bath. The solid was filtered, washed with cold methanol (50 ml) and dried in vacuo at 40° C. overnight to afford the title compound as pale brown crystals.

Workup

  1. concentrationThe reaction mixture was concentrated in vacuo
  2. additionTo the crude residue in methanol (510 ml) was added activated charcoal (25 g)
  3. filtrationThe suspension was filtered hot
  4. temperaturecooled
  5. stirringwas stirred in an ice bath
  6. filtrationThe solid was filtered
  7. washwashed with cold methanol (50 ml)
  8. customdried in vacuo at 40° C. overnight

Sources & evidence

ORD record
ord-937c90e9fcdc4012a6db69a34364f29f
Source dataset
uspto-grants-2015_09
Patent number
US09132127B2

Reaction notes

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