Thiourea → 5-(Difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl-carbamimidothioic acid methyl ester hydrobromide

Participants

Reaction Steps

To a solution of 19.1 g (purity: 75.0%, 46.3 mmol) of 4-bromomethyl-5-difluoromethoxy-1-methyl-3-trifluoromethyl-1H-pyrazole in 30 ml of ethanol was added 3.5 g (46.3 mmol) of thiourea, followed by 1 hour of heating and refluxing under stirring. The solvent was removed by evaporation under reduced pressure and the residue was washed with a mixed solvent of ethyl acetate and n-hexane to obtain 13.8 g (yield: 77.5%) of 2-(5-difluoromethoxy-1-methyl-3-trifluoromethyl-1H-pyrazole-4-ylmethyl)-isothiourea hydrobromide as white crystals (melting point: 130 to 131° C.).

Provenance & Evidence