116111-72-9

The invention relates to oxime ethers of the formula I STR1 wherein n is 1 or 2, each of R1 and R2 is hydrogen or C1 -C4 alkyl each of R3 and R4 is hydrogen, halogen, C1 -C4 alkyl, C1 -C4 haloalkyl, C1 -C4 alkoxy, C1 -C4 haloalkoxy, C1 -C4 alkylthio, C1 -C4 haloalkylthio, C1 -C4 alkylsulfinyl, C1 -C4 alkylsulfonyl, C1 -C4 haloalkylsulfinyl, C1 -C4 haloalkylsulfonyl or nitro; each of R5 and R6 independently of the other is hydrogen, C1 -C4 alkyl, C1 -C4 haloalkyl, phenyl or phenyl which is substituted by halogen, C1 -C4 alkyl, C1 -C4 haloalkyl, C1 -C4 alkoxy, C1 -C4 haloalkoxy, C1 -C4 alkylthio, C1 -C4 alkylsulfinyl, C1 -C4 alkylsulfonyl, carboxyl, carbamoyl, C 1 -C4 alkylcarbamoyl, nitro or cyano, or R5 and R6 together are also a 2- to 6-membered alkylene or alkenylene chain which may be substituted by C1 -C4 alkyl radicals; X is hydrogen, cyano, nitro, chlorine, C1 -C4 alkyl, C1 -C4 haloalkyl, C3 -C6 cycloalkyl, carboxyl, carbamoyl, C1 -C4 alkylcarbonyl, C1 -C4 alkoxycarbonyl or C1 -C4 alkylcarbamoyl. The oxime ethers of the formula I are able to act as antidotes or safeners to protect cultivated plants from the phytotoxic effects of herbicides. Such cultivated plants are preferably sorghum, cereals, maize and rice.

The proton-catalyzed fragmentation of 4-methylene-1,3-dioxolanes 2 by weak acids (pK > 4.3) or weak acidic ion exchangers leads in good yields to β-oxa-γ, δ-enones 5 which are thus easily and generally available for the first time.

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