Benzaldehyde → 3-Phenylpyrazin-2(1H)-one

HRID 1995057Notes

Reaction equation

HRID 1995057 reaction equation
[C-:1]#[N:2].[K+].[Cl-].[NH4+:5].[CH:6](=O)[C:7]1[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=1.Cl.[CH:15]([CH:17]=O)=O.[OH-:19].[Na+]>C(Cl)Cl.CO.O>[C:7]1([C:6]2[C:1](=[O:19])[NH:2][CH:15]=[CH:17][N:5]=2)[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=1

Participants

10

Reactant 6

HCID 240BenzaldehydeHCID 313Hydrochloric AcidHCID 7860GlyoxalHCID 9032Potassium CyanideHCID 14798Sodium HydroxideHCID 25517Ammonium Chloride

Product 1

HCID 1559663-Phenylpyrazin-2(1H)-one

Reagents, catalysts & solvents 3

HCID 887MethanolSolventHCID 962WaterSolventHCID 6344DichloromethaneSolvent

Conditions

Temperature
25 °C

Procedure

To a stirred solution of 0.3 mol. of potassium cyanide and 0.3 mol. of ammonium chloride in 100 ml. of water is added a solution of 0.3 mol. of benzaldehyde (Aldrich Chemical Co.) in 100 ml. of methanol. The reaction mixture is stirred at 25° C. for 6.0 hr. The oil layer is isolated and dissolved in methylene chloride. The solution is washed with water, dried and evaporated to give a brown oil. The oil is stirred with 150 ml. of concentrated hydrochloric acid for 1.0 hr. at 45° C. to precipitate phenylglycinamide hydrochloride. The precipitate is dissolved in 120 ml. of water stirred and cooled to 2° C. A solution of 4.8 g. (0.03 mol.) of 40% aqueous glyoxal is added, followed by dropwise addition of 6.0 ml. of 10 N sodium hydroxide. The reaction mixture is stirred for 5.0 hr. at 2° C. and then filtered. The filtrate is acidified to pH 6 with 3.0 ml. of 10 N hydrochloric acid and the precipitate of title compound is collected by filtration.

Workup

  1. customThe oil layer is isolated
  2. washThe solution is washed with water
  3. customdried
  4. customevaporated
  5. customto give a brown oil
  6. stirringThe oil is stirred with 150 ml
  7. customat 45° C. to precipitate phenylglycinamide hydrochloride
  8. dissolutionThe precipitate is dissolved in 120 ml
  9. stirringof water stirred
  10. temperaturecooled to 2° C
  11. additionfollowed by dropwise addition of 6.0 ml
  12. stirringThe reaction mixture is stirred for 5.0 hr
  13. filtrationat 2° C. and then filtered
  14. filtrationof 10 N hydrochloric acid and the precipitate of title compound is collected by filtration

Sources & evidence

ORD record
ord-b967161755a14de985ee6f8a78251f6e
Source dataset
uspto-grants-1983_09
Patent number
US04402958

Reaction notes

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