Water → 4-[(2-Fluoro-3-trifluoromethylphenyl)-hydroxyimino-methyl]-piperidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

A mixture of 4-(2-Fluoro-3-trifluoromethyl-benzoyl)-piperidine-1-carboxylic acid tert-butyl ester (9.00 g, 24.0 mmol), hydroxylamine hydrochloride (2.00 g, 28.8 mmol) and pyridine (50 mL) was stirred at room temperature under nitrogen overnight. The yellow reaction solution was poured into cold water (500 mL) and the mixture aged at 0° C. for 1 h. The product was collected by filtration, washed with water, and dried under vacuum at 50° C. to afford 9.54 g of a while solid. Trituration of the solid with hot 25% ethyl acetate/heptane afforded 8.50 g (91%) of the desired product as a white solid. Proton NMR showed product to be a 3.8 to 1 mixture of isomers.

Provenance & Evidence