Trifluoroacetic anhydride → 5-(3,5-dichloro-phenyl)-3-[4-(1H-pyrazol-4-yl)-naphthalen-1-yl]-5-trifluoromethyl-4,5-dihydro-isoxazole

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Reaction Steps

Trifluoroacetic acid anhydride (0.18 ml) is added to a solution of 4-{4-[5-(3,5-dichloro-phenyl)-5-trifluoromethyl-4,5-dihydro-isoxazol-3-yl]-naphthalen-1-yl}-pyrazole-1-carboxylic acid tert-butyl ester (135 mg) in dichloromethane (1 ml). After 1 hour at room temperature an aqueous solution of sodium hydroxide (30%) is added. The aqueous phase is extracted with dichloromethane and the combined organic phases are dried over MgSO4 and concentrated in vacuo. The crude product is purified on a semi-preparative HPLC to yield 5-(3,5-dichloro-phenyl)-3-[4-(1H-pyrazol-4-yl)-naphthalen-1-yl]-5-trifluoromethyl-4,5-dihydro-isoxazole as a colorless solid: m.p. 117-120° C. (compound 1.17, table 1).

Provenance & Evidence