Hydrochloric Acid → 3-(Methoxycarbonyl)amino-4-methoxy-isoxazole-5-carboxylic acid

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Reaction Conditions

Reaction Steps

A mixture of 2.50 g (0.011 mmol) of methyl-3-(methoxycarbonyl)amino-4-methoxy-isoxazole-5-carboxylate (prepared according to the method described in W. Kloetzer, J. Schantz, Monatsh. Chem., 1965, 102–115) and 1.30 g of powdered sodium hydroxide dissolved in 9 ml of water is heated at 90° C. for 3 hours. After cooling, the mixture is acidified to pH=2 with concentrated hydrochloric acid, controlling the temperature so as not to exceed 5° C. After 1 hour of stirring at 0° C., the precipitate obtained is filtered off and washed with cold water. There is obtained 2.01 g (86% yield) of a white solid (M+1=217).

Provenance & Evidence