One of the active principles of Amanita muscaria, 5-aminomethyl-3-hydroxyisoxazole (I) has been synthesised from 3-bromo-5-methylisoxazole by way of 3-methoxyisoxazole-5-acetic acid (XIII), and from 3-methoxyisoxazole-5-carboxylic acid (XXa) by reduction of its amide with diborane. Analogues of (I) with methyl and ethyl substituents in the 4-position have been prepared similarly from 3-hydroxy-4,5-dimethylisoxazole