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

Participants

Reaction Steps

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).

Provenance & Evidence