1-(3-Substituted benzyl)-3-halogeno-4-(1-halogenoalkyl)-2-pyrrolidinones of the general formula (I): ##STR1## where X represents a hydrogen atom or halogen atom, Y and Z each represents a chlorine atom or bromine atom, and R represents an alkyl group with 2 to 4 carbon atoms, are herbicides useful in rice paddy fields to control weeds therein, especially Echinochloa crusgalli and can be produced subjecting the corresponding 3-dihalogeno compounds to dehalogenation to remove one of the halogen atoms or by cyclizing a 2,2-dihalogenoacetamide derivative represented by the general formula (II) under the presence of an appropriate catalyst; ##STR2## in which X, Y, Z and R respectively have the same meanings as described above.
通式(I)中,1-(3-取代苯基)-3-卤代-4-(1-卤代烷基)-2-
吡咯酮,其中X代表氢原子或卤素原子,Y和Z分别代表
氯原子或
溴原子,R代表具有2至4个碳原子的烷基基团,是在稻田中控制其中杂草,特别是稗草的
除草剂,并且可以通过将相应的3-二卤代化合物进行去卤化以去除其中的一个卤素原子,或者通过在适当催化剂的存在下使通式(II)所表示的2,2-二卤代乙酰胺衍
生物环化来制备;其中X、Y、Z和R分别具有上述相同的含义。