Water → 1-(5-methoxycarbonyl-4-nitro-2-trifluoromethyl-phenyl)-1H-[1,2,4]triazole-3-carboxylic acid ethyl ester

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Reaction Conditions

Reaction Steps

A solution of 613 mg (14.0 mmol) of sodium hydride in 10 ml of 1-methyl-2-pyrrolidinone is cooled to 0-5° C. and treated dropwise with a solution of 1.74 g (12.4 mmol) of 1H-[1,2,4]triazole-3-carboxylic acid ethyl ester in 10 ml of 1-methyl-2-pyrrolidinone over 8 minutes. The mixture is stirred for 1 hour at 0-5° C. and a solution of 3.00 g (11.2 mmol) of 5-fluoro-2-nitro4-trifluoromethyl-benzoic acid methyl ester in 10 ml of 1-methyl-2-pyrrolidinone is added. The mixture is allowed to warm slowly to room temperature and stirred for 18 hours under N2. It is poured into water and extracted with ethyl acetate. The organic phase is separated and dried over Na2SO4, filtered and concentrated in vacuo. The residue is purified by flash chromatography (SiO2, hexane/ethyl acetate 1:1) and the mixed fractions are recrystallized in toluene to provide overall 3.12 g (71%) of 1-(5-methoxycarbonyl-4-nitro-2-trifluoromethyl-phenyl)-1H-[1,2,4]triazole-3-carboxylic acid ethyl ester, m.p. 190-192° C.

Provenance & Evidence