Sodium Hydroxide → 3-[1,1-Dimethyl-2-(tetrahydropyran-2-yloxy)-ethyl]-isoxazol-5-ylamine

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Reaction Steps

To a stirred solution of 134 g (0.60 mol) of 4,4-dimethyl-3-oxo-5-(tetrahydro-pyran-2-yloxy)-pentanenitrile and 51.3 g (1.28 mol) of sodium hydroxide in water (1.3 L) are added 48.9 g (0.30 mol) of hydroxylamine sulfate. The reaction mixture is stirred at reflux for 18 hours. After this time, the reaction mixture is cooled to room temperature and extracted with ethyl acetate (3×0.8 L). The organic layers are combined and washed with brine (1 L), dried over Na2SO4 and filtered. The filtrate is concentrated under reduced pressure. The residual brown oil is triturated with hexanes (0.8 L) while stirring and the resulting precipitate is isolated by filtration and dried in a vacuum oven for 2 d to yield 85 g of 3-[1,1-dimethyl-2-(tetrahydro-pyran-2-yloxy)-ethyl]-isoxazol-5-ylamine as a yellow solid. Yield 60%; m/z 241 [M+H], 157 [M+H-84]; 1H NMR (400 MHz, DMSO-d6) δ ppm 1.18 (3H, s), 1.19 (3H, s), 1.45-1.75 (6H, m), 3.26 (1H, d, J=9.3 Hz), 3.4 (1H, m), 3.59 (1H, d, J=9.3 Hz), 3.68 (1H, m), 4.5 (1H, m), 4.88 (1H, s), 6.43 (2H, s).

Provenance & Evidence