4,4-二甲基异噁唑-3-酮的合成

Synthesis of 4,4-Dimethyl-3-isoxazolidinone

以氯代特戊酰氯(Ⅱ)为原料,与盐酸羟胺(Ⅲ)反应,得3 氯 N 羟基 2,2 二甲基丙酰胺(Ⅳ)。Ⅳ与氢氧化钠反应,得4,4 二甲基异口恶唑 3 酮(Ⅰ),总收率达84%。优化的反应条件是:在酰化反应时通过降低反应温度来抑制盐酸羟胺与氯代特戊酰氯的分解,收率91 4%;在闭环反应中,反应时间为4～5h,收率92 5%,均采用价廉的w(NaOH)=30%工业液碱。并对产品结构进行了1HNMR,IR,MS确定。

3-Chloro-N-hydroxy-2,2-dimethylpropanamide(Ⅳ) was prepared by reaction of chloro-pivalyl chloride(Ⅱ) with hydroxylamine hydrochloride(Ⅲ).By decreasing the reaction temperature to inhibit decomposition of Ⅱ and Ⅲ,the yield of Ⅳ was 91.4%.Then Ⅳ reacted with sodium hydroxide for 4～5 h to form 4,4-dimethyl-3-isoxazolidinone(Ⅰ) in 92.5% yield.The overall yield was over 84%.The cheap alkali liquor〔w(NaOH)=30%〕was used in both reactions.Structure of the product was identified by ~1HNMR,IR and MS spectra.