Herbicidal heterocycles
a heterocycle and herbicide technology, applied in the field of pyrazoles and pyrazolines, can solve the problems of increasing consumer costs
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example 1
Preparation of 5-[3-(1,1-dimethylethyl)-1H-pyrazol-1-yl]-3-[3-(trifluoromethyl)phenyl]-4-thiazolidinone
[0159] To tetrahydrofuran (15 mL) at about −10° C. stirred under a nitrogen atmosphere were added diethyl azodicarboxylate (0.66 mL, 4.18 mmol), 5-hydroxy-3-[3-(trifluoromethyl)phenyl]-4-thiazolidinone (1 g, 3.8 mmol), 3-(1,1-dimethylethyl)-1H-pyrazole (0.48 g, 3.8 mmol) and triphenylphosphine (1.2 g, 4.41 mmol). After the addition, the reaction mixture was allowed to warm up to room temperature, and stirred overnight under a nitrogen atmosphere. The reaction mixture was concentrated, and the residue taken into a small amount of methylene chloride and then filtered. The filtrate was loaded on silica gel in a medium pressure liquid chromatography column and eluted with a solution of 20% ethyl acetate and 80% hexanes followed by a solution of 33% ethyl acetate and 67% hexanes to give 0.26 g of a crude product. The crude product was further purified by medium pressure liquid chromato...
example 2
Preparation of 5-[3-(1,1-dimethylethyl)-1H-pyrazol-1-yl]-3-[3-(trifluoromethyl)phenyl]-4-thiazolidinone
[0161] To a stirred solution of thionyl chloride (5.3 mL, 73 mmol) in 120 mL of methylene chloride at ˜10° C. was slowly added 3-(1,1-dimethylethyl)-1H-pyrazole (11.32 g, 91 mmol). The resulting solution was stirred for ˜20 minutes and was then cooled further to ˜0° C. To this solution was added N,N-diisopropylethylamine (26.5 mL, 152 mmol) dropwise at ˜0° C. and then 5-hydroxy-3-[3-trifluoromethyl)phenyl]-4-thiazolidinone (16 g, 61 mmol) portionwise at temperatures between 0° C. and 10° C. After the addition, the reaction mixture was allowed to warm up to room temperature, and stirred at room temperature for 3 days. To the reaction mixture was then added 120 mL of concentrated sodium bicarbonate aqueous solution. The methylene chloride layer was separated and the aqueous layer was extracted twice with methylene chloride (˜120 mL each). The methylene chloride layers were combined,...
example 3
Preparation of 3-[3-(1,1-dimethylethyl)-1H-pyrazol-1-yl]-1-[3-(trifluoromethyl)phenyl]-2-pyrrolidinone
[0163] To a solution of 3-(1,1-dimethylethyl)-1H-pyrazole (0.22 g, 1.8 mmol) in N,N-dimethylformamide (20 mL) under nitrogen at room temperature was added 60% sodium hydride in mineral oil (90 mg, 2.16 mmol). After the addition, the mixture was stirred at room temperature for ˜15 minutes, and 3-hydroxy-1-[3-(trifluoromethyl)phenyl]-2-pyrrolidinone methanesulfonate (0.5 g, 1.8 mmol) was added. The resulting reaction mixture was stirred at room temperature overnight and then poured into water (˜100 mL). The aqueous layer was extracted twice with ethyl acetate (˜30 mL each; brine solution was added to separate the two layers). The organic extracts were combined, dried over MgSO4 and filtered. The filtrate was concentrated and the residue purified by column chromatography (silica gel, ˜20% ethyl acetate / 80% hexanes) to give the title compound, a compound of this invention, as a yellow ...
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