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

HRID 1756275Notes

Reaction equation

HRID 1756275 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
20 °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. temperaturethat maintained the reaction mixture temperature at about 8° to 12° C
  5. additionThe complete addition required about 30 minutes
  6. additionUpon completion of addition
  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-3d2f93a1e08844ceaffc3fe9cab7662b
Source dataset
uspto-grants-1995_08
Patent number
US05440045

Reaction notes

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