Sodium Hydroxide → 3-(4-Bromo-5-methyl-thiophen-2-yl)-5-(3,5-dichloro-phenyl)-5-trifluoromethyl-4,5-dihydro-isoxazole

Beteiligte Stoffe

Reaktionsschritte

Hydroxylamine hydrochloride (13 g) and NaOH (18 g) are added to a solution of 1-(4-bromo-5-methyl-thiophen-2-yl)-3-(3,5-dichloro-phenyl)-4,4,4-trifluoro-but-2-en-1-one (84 g, 71% purity) in EtOH (1000 ml) at room temperature. After 12 hours at room, the reaction mixture is concentrated in vacuo, diluted with diethylether and water. The aqueous phase is separated and further extracted two times with diethylether. The organic phases are combined, washed with a saturated aqueous solution of NaCl, dried over MgSO4 and concentrated in vacuo. The crude product is purified by chromatography on silica gel (1800 g) eluting with a mixture of heptane and dichloromethane (4:1) to yield 3-(4-bromo-5-methyl-thiophen-2-yl)-5-(3,5-dichloro-phenyl)-5-trifluoromethyl-4,5-dihydro-isoxazole (47 g) as a light brown crystals.

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