A use of compounds of formula wherein X is O, NR 7 or S, SO, SO 2; Y is C 1 -C 6 -alkyl, C 3 -C 6 -alkenyl, C 3 -C 6 -alkynyl where the radicals are unsubstituted or substituted by 1, 2, 3, 4 or 5 identical or different substituents selected from the group consisting of halogen, C 1 -C 6 -alkyl, C 1 -C 6 -haloalkyl, C 1 -C 6 -alkoxy, C 1 -C 6 -haloalkoxy, C(=O)O(C 1 -C 6 -alkyl) and phenyl which is unsubstituted or substituted by halogen, C 1 -C 6 -alkyl, C 1 -C 6 -haloalkyl; R 1 is selected from the group consisting of H and C 1 -C 6 -alkyl; R 2 is selected from the group consisting of H and C 1 -C 6 -alkyl; R 3 is selected from the group consisting of H, halogen, OH, CN, amino, NO 2, C 1 -C 6 -alkyl, C 3 -C 6 -alkenyl, C 3 -C 6 -alkynyl, C 1 -C 6 -alkoxy, C 2 -C 6 -alkenyloxy, C 2 -C 6 -alkynyloxy, (C 1- C 6 -alkoxy)-C 1 -C 6 -alkyl, (C 1 -C 6 -alkoxy)-C 1 -C 6 -alkoxy, (C 1 -C 6 -alkoxy)-C 3 -C 6 -alkenyl, (C 1 -C 6 -alkoxy)-C 3 -C 6 -alkynyl, where the aliphatic parts of the aforementioned radicals are unsubstituted, partly or completely halogenated; R 4 is selected from the group consisting of H, halogen, OH, CN, amino, NO 2, C 1 -C 6 -alkyl, C 3 -C 6 -alkenyl, C 3 -C 6 -alkynyl, C 1 -C 6 -alkoxy, C 2 -C 6 -alkenyloxy, C 2 -C 6 -alkynyloxy, (C 1 -C 6 -alkoxy)-C 1 -C 6 -alkyl, (C1-C 6 -alkoxy)-C 1 -C 6 -alkoxy, (C 1 -C 6 -alkoxy)-C 3 -C 6 -alkenyl, (CrC 6 -alkoxy)-C 3 -C 6 -alkynyl, where the aliphatic parts of the aforementioned radicals are unsubstituted, partly or completely halogenated; R 5 is selected from the group consisting of H, halogen, OH, CN, amino, NO 2, C 1 -C 6 -alkyl, C 3 -C 6 -alkenyl, C 3 -C 6 -alkynyl, C 1 -C 6 -alkoxy, C 2 -C 6 -alkenyloxy, C 2 -C 6 -alkynyloxy, (C 1 -C 6 -alkoxy)-C 1 -C 6 -alkyl, (C 1 -C 6 -alkoxy)-C 1 -C 6 -alkoxy, (C 1 -C 6 -alkoxy)-C 3 -C 6 -alkenyl, (C 1 -C 6 -alkoxy)-C 3 -C 6 -alkynyl, where the aliphatic parts of the aforementioned radicals are unsubstituted, partly or completely halogenated; R 6 is selected from the group consisting of H, C 1 -C 6 -alkyl, C 3 -C 6 -alkenyl, C 3 -C 6 -alkynyl, (C 1 -C 6 -alkoxy)-C 1 -C 6 -alkyl, (C 1 -C 6 -alkoxy)-C 3 -C 6 -alkenyl, (C 1 -C 6 -alkoxy)-C 3 -C 6 -alkynyl, phenyl, phenyl-C 1 -C 6 -alkyl, where the aliphatic and phenyl parts of the aforementioned radicals are unsubstituted, partly or completely halogenated; R 7 is selected from the group consisting of H, C 1 -C 6 -alkyl, C 3 -C 6 -alkenyl, C 3 -C 6 -alkynyl; including their agriculturally acceptable salts for controlling unwanted vegetation. X is O, NR 7 or S, SO, SO 2; Y is C 1 -C 6 -alkyl, C 3 -C 6 -alkenyl, C 3 -C 6 -alkynyl where the radicals are unsubstituted or substituted by 1, 2, 3, 4 or 5 identical or different substituents selected from the group consisting of halogen, C 1 -C 6 -alkyl, C 1 -C 6 -haloalkyl, C 1 -C 6 -alkoxy, C 1 -C 6 -haloalkoxy, C(=O)O(C 1 -C 6 -alkyl) and phenyl which is unsubstituted or substituted by halogen, C 1 -C 6 -alkyl, C 1 -C 6 -haloalkyl; R 1 is selected from the group consisting of H and C 1 -C 6 -alkyl; R 2 is selected from the group consisting of H and C 1 -C 6 -alkyl; R 3 is selected from the group consisting of H, halogen, OH, CN, amino, NO 2, C 1 -C 6 -alkyl, C 3 -C 6 -alkenyl, C 3 -C 6 -alkynyl, C 1 -C 6 -alkoxy, C 2 -C 6 -alkenyloxy, C 2 -C 6 -alkynyloxy, (C 1- C 6 -alkoxy)-C 1 -C 6 -alkyl, (C 1 -C 6 -alkoxy)-C 1 -C 6 -alkoxy, (C 1 -C 6 -alkoxy)-C 3 -C 6 -alkenyl, (C 1 -C 6 -alkoxy)-C 3 -C 6 -alkynyl, where the aliphatic parts of the aforementioned radicals are unsubstituted, partly or completely halogenated; R 4 is selected from the group consisting of H, halogen, OH, CN, amino, NO 2, C 1 -C 6 -alkyl, C 3 -C 6 -alkenyl, C 3 -C 6 -alkynyl, C 1 -C 6 -alkoxy, C 2 -C 6 -alkenyloxy, C 2 -C 6 -alkynyloxy, (C 1 -C 6 -alkoxy)-C 1 -C 6 -alkyl, (C1-C 6 -alkoxy)-C 1 -C 6 -alkoxy, (C 1 -C 6 -alkoxy)-C 3 -C 6 -alkenyl, (CrC 6 -alkoxy)-C 3 -C 6 -alkynyl, where the aliphatic parts of the aforementioned radicals are unsubstituted, partly or completely halogenated; R 5 is selected from the group consisting of H, halogen, OH, CN, amino, NO 2, C 1 -C 6 -alkyl, C 3 -C 6 -alkenyl, C 3 -C 6 -alkynyl, C 1 -C 6 -alkoxy, C 2 -C 6 -alkenyloxy, C 2 -C 6 -alkynyloxy, (C 1 -C 6 -alkoxy)-C 1 -C 6 -alkyl, (C 1 -C 6 -alkoxy)-C 1 -C 6 -alkoxy, (C 1 -C 6 -alkoxy)-C 3 -C 6 -alkenyl, (C 1 -C 6 -alkoxy)-C 3 -C 6 -alkynyl, where the aliphatic parts of the aforementioned radicals are unsubstituted, partly or completely halogenated; R 6 is selected from the group consisting of H, C 1 -C 6 -alkyl, C 3 -C 6 -alkenyl, C 3 -C 6 -alkynyl, (C 1 -C 6 -alkoxy)-C 1 -C 6 -alkyl, (C 1 -C 6 -alkoxy)-C 3 -C 6 -alkenyl, (C 1 -C 6 -alkoxy)-C 3 -C 6 -alkynyl, phenyl, phenyl-C 1 -C 6 -alkyl, where the aliphatic and phenyl parts of the aforementioned radicals are unsubstituted, partly or completely halogenated; R 7 is selected from the group consisting of H, C 1 -C 6 -alkyl, C 3 -C 6 -alkenyl, C 3 -C 6 -alkynyl;