NEW MATERIAL:Optically active R isomers of phenoxycarboxylic acids of formula I (X and Y are H, halogen, CF3 or 1-5C alkyl; R1 and R2 are 1-5C alkyl which may be substituted with 2-6C alkoxycarbonyl, cyano, 1-5C alkylthio which may be substituted with 2-6C alkylcarbonyl, OR4 or formula II; R4 is H, 1-5C alkyl or 1-5C trifluoroalkyl; R5 and R6 are H, 1-5C alkyl, 1-5C alkylsulfonyl or phenyl; R3 is H or 1-5C alkyl) or salts thereof in case of R4 = H.
USE: Useful as a herbicide showing a selective herbicidal action almost without damage to growth of thin leaf crops and capable of selectively killing down broad leaf weeds.
PREPARATION: A compound of formula I is obtained through a compound of formula V synthesized from a compound of formula III and a compound of formula IV.
HIRAMATSU TOSHIYUKI
ICHIKAWA YATARO
