Synthesis of 3-Hydroxyisoxazoles from β-Ketoesters and Hydroxylamine

Abstract

An efficient synthesis of 3-hydroxyisoxazoles from β-ketoesters and hydroxylamine was investigated. The reaction of the sodium salts of β-ketoesters and hydroxylamine at a low temperature, followed by quenching with an excess of cone. HC1 under heating gave predominantly 3-hydroxyisoxazoles involving 4-sulfenylated 3-hydroxyisoxazoles. Starting from the prepared 4-(2, 4-dichlorobenzyl)-3-hydroxy-5-methylisoxazole, a potential herbicidal compound, 4-(2, 4-dichlorobenzoyl)-3-hydroxy-5-methylisoxazole, was also synthesized in five steps.