Hydrochloric Acid → 5-[5-(3,5-Dichloro-phenyl)-5-trifluoromethyl-4,5-dihydro-isoxazol-3-yl]-3-methyl-thiophene-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

LiOH (3.2 g) is added to a solution of 5-[5-(3,5-dichloro-phenyl)-5-trifluoromethyl-4,5-dihydro-isoxazol-3-yl]-3-methyl-thiophene-2-carboxylic acid ethyl ester (9.88 g) in a mixture of THF and water (240 ml, 9:1). After 16 hours at room temperature, LiOH (1.05 g) and THF (150 ml) was added. The reaction mixture was heated at 50° C. for 10 hours. HCl (2N) was added to the reaction mixture until pH 1-2 was obtained. The mixture was then extracted three times with ethyl acetate. The organic phases were combined, washed with water and a saturated aqueous solution of NaCl, dried over Na2SO4 and concentrated in vacuo to yield 5-[5-(3,5-dichloro-phenyl)-5-trifluoromethyl-4,5-dihydro-isoxazol-3-yl]-3-methyl-thiophene-2-carboxylic acid (9.3 g) as brown resin. The crude product is used without further purification.

Provenance & Evidence