A novel process for the preparation of E-2-propyl-2-pentenoic acid and its physiologically compatible salts is described, in which di-n-propyl-ketone-cyanohydrin is used as the starting compound. The compound is either (a) dehydrated with thionyl chloride and the acid nitrile formed is subsequently saponified with a stoichiometric excess of potassium hydroxide, or (b) is initially converted into 2-hydroxy-2-propyl-pentanoic acid and the latter is subsequently dehydrated in the presence of a less than stoichiometric quantity of a tertiary amine at a temperature of at least 200.degree. C. The free acid is optionally converted into the salt form, preferably using the corresponding salts of carbon dioxide in an aqueous acetone solution.
本文描述了一种制备E-
2-丙基-2-戊烯酸及其生理兼容盐的新工艺,其中二-n-丙基-酮腈
水合物被用作起始化合物。该化合物要么(a)通过用
氯化硫酰
脲脱
水,随后用过量的
氢氧化钾皂化生成的酸腈,要么(b)最初转化为
2-羟基-2-丙基戊酸,然后在少于计量的三级胺存在下,在至少200℃的温度下脱
水。
游离酸可以选择转化为盐形式,最好使用
碳酸盐的相应盐在
水合
丙酮溶液中进行。