Cl.[NH2:2]O.C([O-])(O)=O.[Na+].[F:9][C:10]([F:20])([F:19])[C:11]([CH3:18])([CH3:17])[C:12](=[O:16])[CH2:13][C:14]#[N:15].Cl.[OH-].[Na+]>O.CO>[F:9][C:10]([F:19])([F:20])[C:11]([C:12]1[O:16][N:15]=[C:14]([NH2:2])[CH:13]=1)([CH3:18])[CH3:17]To a mixture of hydroxylamine, hydrochloride (3.10 g, 44.7 mmol) in H2O (25 mL) cooled to 0° C. was added NaHCO3 (3.94 g, 46.9 mmol) to adjust to pH=7.5. Then to the mixture was added a solution of 5,5,5-trifluoro-4,4-dimethyl-3-oxopentanenitrile (4 g, 22.33 mmol) in MeOH (25 mL). The mixture was stirred at 65° C. for 15 h. After cooled, the mixture was acidified with conc. HCl to pH=1.0 and then refluxed for 2 h. After cooling, the mixture was neutralized by 4 mol/L NaOH to pH=8.0. The mixture was extracted with DCM/MeOH (10:1). The organic layer was dried over Na2SO4, filtered and concentrated to yield a white solid of 5-(1,1,1-trifluoro-2-methylpropan-2-yl)isoxazol-3-amine (2 g, 9.06 mmol, 40.6% yield): 1H NMR (400 MHz, CDCl3) δ 5.78 (s, 1H), 3.93 (s., 2H), 1.51 (s, 6H); ES-LCMS m/z 195 (M+1).
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