Method for preparing (2,2,2-trifluoroethyl)sulfanylaniline derivatives

A method for preparing (2,2,2-trifluoroethyl)sulfanylaniline derivatives of formula (I):

• in which R1 and R2 are each independently (C1-C3) alkyl or halogen,
• which is characterized in that a 3-aminobenzenethiol of formula (II):
• in which R1 and R2 have the definitions given above,
• is reacted with 1,1,1-trifluoro-2-chloroethane in the presence of a base in a solvent mixture, wherein the solvent mixture comprises:
• (i) a first solvent selected from N-methylpyrrolidone, N-ethylpyrrolidone, N-methylformamide, dimethylformamide, N,N-dimethylacetamide (DMAc), 1,3-dimethyl-2-imidazolidinone, tetramethylurea, sulfolane, dimethyl sulfoxide, acetonitrile, propionitrile, butyronitrile, polyethylene glycols, ethylene carbonate and propylene carbonate;
• and
• (ii) a second solvent selected from tetrahydrofuran (THF), 1,2-dimethoxyethane (DME), 1,4-dioxane, diethyl ether, methyl tertbutyl ether (MTBE), tert-amyl methyl ether (TAME), 2-methyl-THF, cyclopentyl methyl ether, bis(2-methoxyethyl) ether, anisole, ethyl acetate, isopropyl acetate, butyl acetate, pentyl acetate, 3,3-dimethylbutanone, diethyl carbonate, dimethyl carbonate, toluene, xylenes and ethylbenzene.