Acetic Acid → 2-(4-Chloro-2-fluoro-5-hydroxyphenyl)-4-methyl-5-(trifluoromethyl)-3(2H)-pyridazinone

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Reaction Conditions

Reaction Steps

Under a stream of nitrogen gas, 0.295 g of 3,3,3-trifluoro-2-oxopropanal 1-(4-chloro-2-fluoro-5-hydroxyphenylhydrazone), compound 3-1 was dissolved in 2.0 ml of pyridine. To this solution were added 0.113 ml of piperidine and 0.295 g of methylmalonic acid, and the mixture was heated to 70° C. and stirred for 2.5 hours. Then, 2.0 ml of acetic acid was added, and stirring was further continued at 130° C. for 7 hours. The reaction solution was left cooling to room temperature and concentrated under reduced pressure. The residue was diluted with 100 ml of diethyl ether. The diluted solution was washed twice with 20 ml of 3 N hydrochloric acid and once with 30 ml of saturated aqueous sodium bicarbonate solution, dried with magnesium sulfate, filtered, and concentrated under reduced pressure. The residue was subjected to column chromatography to give 0.184 g of 2-(2-fluoro-4-chloro-5-hydroxyphenyl)-4-methyl-5-trifluoromethylpyridazin-3-one, compound 5-1.

Provenance & Evidence