| 摘要 |
PURPOSE:To obtain the titled substance useful as a synthetic intermediate for agricultural germicides, medicines and agricultural chemicals in high yield, by reacting a beta-keto ester derivative with hydroxylamine in the presence of a base at a low temperature, and heat-treating the reaction mixture with an acid. CONSTITUTION:A compound of formula I (R<1> is lower alkyl, cycloalkyl, phenyl, thenoyl or furoyl, etc.; R<2> is H, alkyl, alkenyl, cycloalkyl or aralkyl, etc.; R<3> is lower alkyl) is reacted with hydroxylamine in the presence of a base, preferably an alkali metal hydroxide, at -78--10 deg.C, and an acid, e.g. hydrochloric acid, sulfuric acid or nitric acid, in an equivalent amount of preferably 5-15 times of that of the compound of formula I is added to the reaction product without isolating the reaction product in one step. The reaction mixture is then heated rapidly to 50-150 deg.C to afford the aimed compound of formula II. EFFECT:The formation of 5-hydroxy isomers can be suppressed to a completely negligible extent.
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