Pentanenitrile, 4,4-dimethyl-3-oxo- → 3-Isoxazolamine, 5-(1,1-dimethylethyl)-

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Reaction Steps

In adding the hydroxylamine hydrochloride to the reaction mixture, it appears that a quick addition is preferable. Best results appear to be obtained by adding an aqueous solution of the hydroxylamine hydrochloride to the basic solution of the pivalyl acetonitrile, and then, within the first 15 to 30 minutes, adjusting the pH to within the range of from about 5.0 to about 8.0, preferably from about 6.0 to about 7.0, with the pH range of choice being pH about 6.2 to about 6.5. This careful control of the pH of the reaction mixture is important in order to obtain the maximum yield of the 3-amino-5-(t-butyl)isoxazole since the reaction is very sensitive to the pH. A pH lower than about 5.0 results in the formation of an isoxazolone compound as the principal product. Higher pH values, that is, above about pH 8.0, result in unacceptably large amounts of the 5-amino-3-(t-butyl)isoxazole, compared to the amount of the desired 3-amino-5-(t-butyl)isoxazole. Even at pH 7.0, the ratio of the desired 3-amino compound to the 5-amino compound is less desirable.

Provenance & Evidence