Nitric Acid → HCID 19080754, compound

Participants

Reaction Steps

1-Ethyl-5-methoxy-3-(trifluoromethyl)pyrazole (15.2 g, 0.0785 mmol) was added dropwise with stirring and cooling at about 0° C. to 150 mL of concentrated sulfuric acid and then 10.5 mL of 70 percent nitric acid (0.235 mmol) was added, also dropwise with stirring at about 0° C. The mixture was then allowed to warm to ambient temperature and stir overnight. An aliquot was removed, neutralized to a pH of about 11, extracted with dichloromethane, and analyzed by gas chromatography. Since there was still some starting material present another about 0.8 mmol of concentrated nitric acid was added with stirring and the mixture was allowed to react for 5 hours. Analysis of an aliquot as before did not reveal any remaining starting material so the mixture was poured slowly into 500 g of ice. The mixture was stirred for 15 min and was then extracted with dichloromethane (4×200 mL). The extracts were combined to obtain an acidic blue-green organic mixture. This was diluted with 100 mL of water and neutralized with 50 percent aqueous sodium hydroxide. The mixture, which turned yellow-orange, was separated into phases and the organic layer was dried over magnesium sulfate, filtered, and concentrated under reduced pressure to obtain 12.4 g of the title compound as a yellow oil.

Provenance & Evidence