Acetaldehyde → 3-Methyl-1-phenyl-4,5-dihydro-1H-1,2,4-triazol-5-one

HRID 1657191Notes

Reaction equation

HRID 1657191 reaction equation
[C:1]1([NH:7][NH2:8])[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[CH:9](=O)[CH3:10].[O-:12][C:13]#[N:14].[Na+].Cl[O-].[Na+]>C(O)(=O)C.O>[CH3:9][C:10]1[NH:14][C:13](=[O:12])[N:7]([C:1]2[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=2)[N:8]=1

Participants

7

Reactant 4

HCID 177AcetaldehydeHCID 7516PhenylhydrazineHCID 517096Sodium CyanateHCID 23665760Sodium Hypochlorite

Product 1

HCID 1355376213-Methyl-1-phenyl-4,5-dihydro-1H-1,2,4-triazol-5-oneYield 76.1%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolvent2×HCID 962WaterSolvent2×

Conditions

Temperature
10 °C

Procedure

In a 50 gallon reactor, a stirred solution of 12 pounds (0.111 lb mole) of phenylhydrazine in 115 pounds of glacial acetic acid was cooled to about 5° to 10° C., and a solution of 5.2 pounds (0.087 lb mole) of acetaldehyde in 6.1 pounds of acetic acid was added at a rate that maintained the reaction mixture temperature at about 12° to 15° C. The complete addition required about five minutes. Immediately upon completion of addition, a cold solution (about 15° C.) of 7.6 pounds (0.117 lb mole) of sodium cyanate in 72 pounds of water was added at a rate that maintained the reaction mixture temperature at about 8 to 12° C. The complete addition required about 30 minutes. Upon completion of addition, the reaction mixture was stirred for 20 minutes and then was warmed to about 20° C. A solution of 13.3 pounds (0.179 lb mole) of sodium hypochlorite in 119.7 pounds of water was then added at a rate that maintained the reaction mixture temperature at 25° to 40° C. The complete addition required about one hour. Upon completion of addition, the reaction mixture was stirred for about one hour, and then about 220 pounds (approximately 72%) of the acetic acid/water solvent was removed by distillation under vacuum (50 mm Hg). Water, 82 pounds, was added, and the resultant slurry was cooled to 25° C. The product was isolated by centrifugation and washed on the centrifuge with water. The product was dried at 70° C. under vacuum, yielding 14.8 pounds of 84.4% pure 4,5-dihydro-3-methyl-1-phenyl-1,2,4-triazol-5(1H)-one (64.2% yield).

Workup

  1. temperaturethat maintained the reaction mixture temperature at about 12° to 15° C
  2. additionThe complete addition required about five minutes
  3. additionImmediately upon completion of addition
  4. additionThe complete addition required about 30 minutes
  5. additionUpon completion of addition
  6. temperaturewas warmed to about 20° C
  7. temperaturethat maintained the reaction mixture temperature at 25° to 40° C
  8. additionThe complete addition required about one hour
  9. additionUpon completion of addition
  10. stirringthe reaction mixture was stirred for about one hour
  11. customabout 220 pounds (approximately 72%) of the acetic acid/water solvent was removed by distillation under vacuum (50 mm Hg)
  12. additionWater, 82 pounds, was added
  13. temperaturethe resultant slurry was cooled to 25° C
  14. customThe product was isolated by centrifugation
  15. washwashed on the centrifuge with water
  16. customThe product was dried at 70° C. under vacuum

Sources & evidence

ORD record
ord-366ddb3d218041abab1e0170b4677cb8
Source dataset
uspto-grants-1993_10
Patent number
US05256793

Reaction notes

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