Dichloromethane → 5-Chloro-2-methyl-4-(o-tolyl)-2,4-dihydro[1,2,4]triazol-3-one

HRID 1106704Notes

Reaction equation

HRID 1106704 reaction equation
C[N:2](C)[NH:3][C:4]([NH:6][C:7]1[CH:12]=[CH:11][CH:10]=[CH:9][C:8]=1[CH3:13])=[O:5].Cl[C:16]([Cl:26])(OC(=O)OC(Cl)(Cl)Cl)Cl.[CH2:27](Cl)Cl>>[Cl:26][C:16]1[N:6]([C:7]2[CH:12]=[CH:11][CH:10]=[CH:9][C:8]=2[CH3:13])[C:4](=[O:5])[N:3]([CH3:27])[N:2]=1

Participants

4

Reactant 3

HCID 6344DichloromethaneHCID 94429TriphosgeneHCID 46125821,1-Dimethyl-4-(O-tolyl)semicarbazide

Product 1

HCID 187898205-Chloro-2-methyl-4-(o-tolyl)-2,4-dihydro[1,2,4]triazol-3-oneYield 64%

Procedure

To a solution of 11.1 g of the title compound of Step A dissolved in 600 mL of methylene chloride under nitrogen was added 17.1 g of triphosgene. The solution was heated at reflux overnight, cooled, and then concentrated under reduced pressure. The resulting residue was dissolved in ethyl acetate, washed with water and then washed with saturated aqueous NaCl. The organic phase was dried (MgSO4), filtered, and concentrated under reduced pressure. The residue was purified by flash chromatography (30-50% ethyl acetate/hexanes as eluent) to afford 8.25 g (64% yield) of the title compound of Step B. 1H NMR (CDCl3): δ 7.42-7.30 (m,3H), 7.17 (d,1H), 3.54 (s,3H), 2.22 (s,3H).

Workup

  1. temperatureThe solution was heated
  2. temperatureat reflux overnight
  3. temperaturecooled
  4. concentrationconcentrated under reduced pressure
  5. dissolutionThe resulting residue was dissolved in ethyl acetate
  6. washwashed with water
  7. washwashed with saturated aqueous NaCl
  8. dry with materialThe organic phase was dried (MgSO4)
  9. filtrationfiltered
  10. concentrationconcentrated under reduced pressure
  11. customThe residue was purified by flash chromatography (30-50% ethyl acetate/hexanes as eluent)

Sources & evidence

ORD record
ord-17079502dcb3416b8b5f3071797516c7
Source dataset
uspto-grants-2000_05
Patent number
US06057352

Reaction notes

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