Chlorodifluoromethane → 2-(4-Chloro-2-fluoro-5-methoxyphenyl)-4-(difluoromethyl)-5-methyl-2,4-dihydro-3H-1,2,4-triazol-3-one

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Reaction Conditions

Reaction Steps

A stirred mixture of 10.0 g (0.039 mole) of 1-(4-chloro-2-fluoro-5-methoxyphenyl)-4,5-dihydro-3-methyl-1,2,4-triazol-5(1H)-one, 10.0 g (0.031 mole) of tetrabutylammonium bromide and 10.0 grams (0.25 mole) of sodium hydroxide in 250 mL of cyclohexane was warmed to 60° C. Chlorodifluoromethane (10.0 g, 0.12 mole) was bubbled into the reaction mixture. After complete addition the reaction mixture was warmed to reflux where it stirred for one hour. The hot solution was decanted from a pot residue and cooled to ambient temperature. Methylene chloride was added to the cooled mixture to dissolve a solid precipitate. The mixture was washed with 10% hydrochloric acid then with an aqueous 10% sodium hydroxide solution. The organic layer was dried with anhydrous magnesium sulfate and filtered. The filtrate was concentrated under reduced pressure to yield 5.0 g of 1-(4-chloro-2-fluoro-5-methoxyphenyl)-4-difluoromethyl-4,5-dihydro-3-methyl-1,2,4-triazol-5(1H)-one; mp 86°-88° C.

Provenance & Evidence