HYDANTOIN DERIVATIVE, THESE PRODUCTION, HERBICIDE CONTAININ THE SAME AS ACTIVE INGREDIENT

PROBLEM TO BE SOLVED: To obtain a new hydantoin derivative which has excellent herbicidal activity and is readily producible. SOLUTION: This derivative is represented by formula I [X is O, S; X is H, a halogen, a 1-8C alkyl; X is H, a halogen, a 1-8C alkyl, -Y-CH(R )C(=O)OR (Y is O, S; R is H, a 1-4C alkyl; R is a 1-6C alkyl, an aralkyl); X is H, a halogen, a 1-8C alkyl, ZR (Z is O, S; R is H, a 1-11C alkyl)], typically 2-(4- chloro-5-cyclopentyloxy-2-fluorophenyl)-5,6-dihydroimidazo[1,5-a]pyrid ine-1,3-[2H,7 H]dione. In order to obtain this derivative, for example, an aryl iso(thio)cyanate derivative of formula III [X ' is H, a halogen, a 1-8C alkyl; X ' is H, a halogen, a 1-8C alkly, ZR ' (R ' is a 1-11C alkly, a 3-8C cycloalkyl)] is allowed to react with a dehydropipecolinic acid derivative of formula IV (R is a H, an 1-6C alkyl).