The present invention provides an industrial process for efficiently preparing a 3-(substituted phenyl)-5-isopropylidene-1,3-oxazolidine-2,4-dione derivative having a potent herbicidal activity without using phosgene or the like. The present invention relates to a process for preparing a 3-(substituted phenyl)-5-alkylidene-1,3-oxazolidine-2,4-dione derivative represented by general formula (III), which comprises reaction of an N-(substituted phenyl)carbamate represented by general formula (I) with a 2-hydroxy-3-alkenoate represented by-general formula (II) or with a 3-alkoxy-2-hydroxyalkanoate represented by general formula (IV): ##STR1## (wherein Ar is a substituted phenyl group, R.sup.1 is an alkyl group having a carbon number of from 1 to 6, R.sup.2 and R.sup.3 are independently hydrogen atoms or alkyl groups having carbon numbers of from 1 to 12, and R.sup.4 and R.sup.5 are independently alkyl groups having carbon numbers of from 1 to 6).
本发明提供了一种工业过程,用于高效制备具有强大除草活性的3-(取代苯基)-5-异丙基亚甲基-1,3-
噁唑烷-2,4-二酮衍
生物,而不使用
光气等。本发明涉及一种制备3-(取代苯基)-5-烷基亚甲基-1,3-
噁唑烷-2,4-二酮衍
生物的过程,该衍
生物由通式(III)表示,其中包括将通式(I)表示的N-(取代苯基)
氨基甲酸酯与通式(II)表示的2-羟基-3-烯酸酯或通式(IV)表示的3-烷氧基-2-羟基烷酸酯反应:##STR1##(其中Ar是取代苯基,R^1是碳数为1至6的烷基,R^2和R^3分别是氢原子或碳数为1至12的烷基,R^4和R^5分别是碳数为1至6的烷基)。