NEW MATERIAL:A compound expressed by formula I [R1 is H, 1-6C alkyl and haloalkyl, 3-6C cycloalkyl, 2-4C alkenyl, 3-4C alkynyl, (substituted) aryl, etc.; R2 is R1 or (substituted) 2-8C alkoxyalkyl; X1 and X2 are halogen; W is O or S].
EXAMPLE: 3-(1,1-Dimethylethyl)-5-[2-fluoro-4-chloro-5-(1-methylethyloxy) phenyl]-1,3,4-oxadiazol-2-one.
USE: An active ingredient of herbicides capable of exhibiting excellent herbicidal activity in a small amount thereof with high safety for cultivated crops and effectively controlling various weeds growing in paddy field and farmland during a period before germination to growth phase.
PREPARATION: A compound expressed by formula II is reacted with phosgene, trichloromethyl chloroformate or thiophosgene in an organic solvent at ambient temperature to 110°C for 1-8hr to afford the compound expressed by formula I.
ARAKI KOICHI
ITO MASAHITO
ENDO KEIJI
KAJI TAKASHI
NARA EMI
