Hydrochloric Acid → 4-[5-(3,5-Dichlorophenyl)-5-trifluoromethyl-4,5-dihydroisoxazol-3-yl]-2-nitro benzoic acid

Participants

Reaction Steps

In a solution of 0.36 g of 4-[5-(3,5-dichlorophenyl)-5-trifluoromethyl-4,5-dihydroisoxazol-3-yl]-2-nitrobenzoic acid ethyl ester in 8 ml of ethanol, a solution of 0.40 g of potassium hydroxide in 2 ml of water was added, and stirred at room temperature for 3 hours. After the completion of the reaction, the reaction mixture was poured in 15 ml of water, adjusted to pH 4 with concentrated hydrochloric acid, then extracted with ethyl acetate (20 ml×2), the organic phase was washed with water, and then dehydrated with saturated sodium chloride aqueous solution and dried over over anhydrous sodium sulfate and the solvent was distilled off under reduced pressure to obtain 0.40 g of crude 4-[5-(3,5-dichlorophenyl)-5-trifluoromethyl-4,5-dihydroisoxazol-3-yl]-2-nitro benzoic acid as pale yellow oily substance. The substance was dissolved in 10 ml of chloroform, and 0.24 g of 2-picolylamine, 0.01 g of 4-(N,N-dimethylamino)pyridine and 0.35 g of 1-[3-(diethylamino)propyl]-3-ethylcarbodiimide hydrochloride were added, and stirred at room temperature for 18 hours. After the completion of the reaction, the solvent was distilled off under reduced pressure. The residue was subjected to purification with medium-pressure preparative liquid chromatography (Yamazen Corporation, medium pressure preparative system; YFLC-Wprep) that was eluted with ethyl acetate-hexane (1:1 to 1:0 gradient), and 0.14 g of the aimed product was obtained as colorless resinous substance.

Provenance & Evidence