Lawesson's reagent → 2-Methyl-5-trifluoromethyl-2H-pyrazole-3-thiol

HRID 1670367Notes

Reaction equation

HRID 1670367 reaction equation
[CH3:1][N:2]1[C:6](=O)[CH:5]=[C:4]([C:8]([F:11])([F:10])[F:9])[NH:3]1.COC1C=CC(P2(SP(C3C=CC(OC)=CC=3)(=S)S2)=[S:21])=CC=1>C1(C)C=CC=CC=1>[CH3:1][N:2]1[C:6](=[S:21])[CH:5]=[C:4]([C:8]([F:11])([F:10])[F:9])[NH:3]1

Participants

4

Reactant 2

HCID 87949Lawesson's reagentHCID 12386161-methyl-3-(trifluoromethyl)-1H-pyrazol-5-ol

Product 1

HCID 190676872-Methyl-5-trifluoromethyl-2H-pyrazole-3-thiolYield 105.7%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

5.25 g of 1-methyl-3-(trifluoromethyl)pyrazol-5-one (8-4) and 10.23 g of Lawesson's reagent were suspended in 300 ml of anhydrous toluene. The suspension was heated under reflux for 6 hours. The reaction solution was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (n-hexane:ethyl acetate=2:1) to produce 4.87 g of 1-methyl-3-(trifluoromethyl)pyrazol-5-thione (8-5).

Workup

  1. temperatureThe suspension was heated
  2. temperatureunder reflux for 6 hours
  3. concentrationThe reaction solution was concentrated under reduced pressure
  4. customThe residue was purified by silica gel column chromatography (n-hexane:ethyl acetate=2:1)

Sources & evidence

ORD record
ord-b6c4205a2576499d80ca371fd38e16f5
Source dataset
uspto-grants-2011_08
Patent number
US07994094B2

Reaction notes

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