NEW MATERIAL:A compound shown by formula I [X1 is halogen; X2 is H or halogen; X3 is halogen or trifluoromethyl; R1 and R2 are (i) lower alkyl, lower alkynyl, etc., or (ii) lower alkoxycarbonylalkyl, alkylcarbonyl, arylcarbonyl, etc., and at least one of R1 and R2 is selected from (ii)].
EXAMPLE: Methyl O-acetyl 5-(2-chloro-4-trifluoromethylphenoxy)-2-nitroben zohydroxamate.
USE: A herbicide. Showing excellent activity on broad-leaved weeds (e.g. Amaranthus viridis L., China jute) especially growing on paddy fields and not providing crops (e.g. maize and soybean) with phytotoxicity.
PREPARATION: An O-acyl-2-nitro-5-(substituted phenoxy)benzhydroxamic acid derivative shown by formula II is reacted with an alkylating agent or an acylating agent in an organic solvent under ice coolingW120°C to give a compound shown by formula I.
KUDO SACHIO
ENDO KEIJI
SUGAYA KIYOSHI
