Novel 5-acyloxy-4(5H)-oxazolonium salts of the formula ##STR1## in which R.sup.1 represents an optionally substituted aliphatic group with up to 12 carbon atoms, an optionally substituted cycloalkyl group with 3 to 10 carbon atoms, an optionally substituted phenyl or naphthyl group or an optionally substituted heterocyclic group and R.sup.2 and R.sup.3 are identical or different and represent a hydrogen atom or an optionally substituted aliphatic group with up to 8 carbon atoms or an optionally substituted phenyl group and X.sup..crclbar. represents the anion of an inorganic or organic acid having a pK.sub.a value of less than 2, are obtained in solution when an acyl cyanide of the general formula R.sup.1 --CO--CN (II) is reacted with a carboxylic acid anhydride of the general formula R.sup.2 --CO--O--CO--R.sup.3 (III) wherein R.sup.1, R.sup.2 and R.sup.3 each have the abovementioned meaning, in the presence of one or more inorganic or organic acids having a pK.sub.a value of less than 2, and if appropriate in the presence of a solvent, and if appropriate at a temperature between 0.degree. and 120.degree. C. The novel oxazolonium salts (I) can be used as intermediate products for the preparation of known, herbicidally active 3,4,6-trisubstituted 1,2,4-triazin-5(4H)-ones.
公式为##STR1##的新型5-酰氧基-4(5H)-
噁唑隆盐,其中R.sup.1代表一个最多有12个碳原子的可选取代脂肪族基团,一个最多有10个碳原子的可选取代环烷基基团,一个可选取代苯基或
萘基团或一个可选取代杂环基团,R.sup.2和R.sup.3相同或不同,表示氢原子或一个最多有8个碳原子的可选取代脂肪族基团或一个可选取代苯基,X.sup..crclbar.表示具有pK.sub.a值小于2的无机或有机酸的阴离子,在溶液中获得,当通式为R.sup.1--CO--CN (II)的酰基
氰与通式为R.sup.2--CO--O--CO--R.sup.3 (III)的
羧酸酐反应时,在具有pK.sub.a值小于2的一个或多个无机或有机酸的存在下,必要时在溶剂的存在下,必要时在0度和120度之间的温度下。新型
噁唑隆盐(I)可用作制备已知的具有除草活性的3,4,6-三取代-1,2,4-
噻唑-5(4H)-酮的中间体。