Sodium Hydroxide → 5-(1,1,1,3,3,3-Hexafluoro-2-hydroxypropan-2-yl)-4,5-dihydroisoxazole-3-carboxylic acid

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Reaction Steps

To a solution of ethyl 5-[2,2,2-trifluoro-1-hydroxy-1-(trifluoromethyl)ethyl]-4,5-dihydroisoxazole-3-carboxylate from example 8-1 (2.58 g, 8.34 mmol) in ethanol (5 ml) was added 1 N NaOH (16.7 mL). The mixture was stirred at r.t. for 1 h. Ethanol was removed under reduced pressure, and to the aqueous solution was added concentrated HCl (1.5 mL). The product was extracted 3 times with EtOAc and 2 times with isopropyl ether, and the combined organic layers were dried over MgSO4. Solvents were removed under reduced pressure to afford the carboxylic acid intermediate as an off-white solid (2.30 g, 98%). 1H NMR (DMSO-d6) δ 3.2-3.4 (m, 2H), 5.12 (t, 3H), 8.6 (br, 1H); ESIMS: m/z 280 (M−H).

Provenance & Evidence