Herbicides

1. A compound of formula (I)

wherein

R 1 is methyl, ethyl, n-propyl, iso-propyl, cyclopropyl, halomethyl, haloethyl, halogen, vinyl, ethynyl, methoxy, ethoxy, halomethoxy or haloethoxy,

R 2 and R 3 are, independently of each other hydrogen, halogen, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkoxy, C 1 -C 6 haloalkoxy, C 2 -C 6 alkenyl, C 2 -C 6 haloalkenyl, C 2 -C 6 alkynyl, C 3 -C 6 alkenyloxy, C 3 -C 6 haloalkenyloxy, C 3 -C 6 alkynyloxy, C 3 -C 6 cycloalkyl, C 1 -C 6 alkylthio, C 1 -C 6 alkylsulfinyl, C 1 -C 6 alkylsulfonyl, C 1 -C 6 alkylsulfonyloxy, C 1 -C 6 haloalkylsulfonyloxy, cyano, nitro; phenyl or phenyl substituted by C 1 -C 4 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, cyano, nitro, halogen, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl or C 1 -C 3 alkylsulfonyl; or heteroaryl or heteroaryl substituted by C 1 -C 4 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, cyano, nitro, halogen, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl or C 1 -C 3 alkylsulfonyl;

R 4 is hydrogen, methyl, ethyl, n-propyl, iso-propyl, halomethyl, haloethyl, halogen, vinyl, ethynyl, methoxy, ethoxy, halomethoxy or haloethoxy,

n is 0, 1, 2 or 3,

X is O, S, S(O) or S(O) 2 ,

R 5 is hydrogen or methyl,

R 6 and R 7 are independently of each other hydrogen, methyl or ethyl, where, when n is 2 or 3, the meanings of the 4 or 6 substituents R 6 and R 7 do not have to be the same,

R 8 is C 1 -C 18 alkyl, C 1 -C 18 haloalkyl, C 3 -C 7 cycloalkyl, C 3 -C 7 cycloalkyl substituted by methyl or ethyl, C 1 -C 6 alkoxyC 1 -C 12 alkyl, C 1 -C 6 alkylthioC 1 -C 12 alkyl, C 3 -C 18 alkenyl or C 3 -C 18 alkenyl substituted by halogen, or C 3 -C 18 alkynyl or C 3 -C 18 alkynyl substituted by halogen, or

R 5 , when n denotes 1 or 2, and R 8 together form a C 2 -C 5 alkylene chain, which is unsubstituted or substituted by methyl or ethyl, or an C 2 -C 5 alkenylene chain, which is unsubstituted or substituted by methyl or ethyl, where, when n is 2, the meanings of the 4 substituents R 6 and R 7 do not have to be the same, or

R 6 , when n denotes 1, and one of R 5 , R 7 and R 8 together form a C 2 -C 5 alkylene chain, which is unsubstituted or substituted by methyl or ethyl, or an C 2 -C 5 alkenylene chain, which is unsubstituted or substituted by methyl or ethyl, and

G is hydrogen, an alkali metal, alkaline earth metal, sulfonium, ammonium or a latentiating group;

and wherein, when G is a latentiating group then G is C 1 -C 8 alkyl, C 2 -C 8 haloalkyl, phenylC 1 -C 8 alkyl (wherein the phenyl is optionally substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl, C 1 -C 3 alkylsulfonyl, halogen, cyano or by nitro), heteroarylC 1 -C 8 alkyl (wherein the heteroaryl is optionally substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl, C 1 -C 3 alkylsulfonyl, halogen, cyano or by nitro), C 3 -C 8 alkenyl, C 3 -C 8 haloalkenyl, C 3 -C 8 alkynyl, C(X a )—R a , C(X b )—X c —R b , C(X d )—N(R c )—R d , —SO 2 —R e , —P(X e )(R f )—R g or CH 2 —X f —R h ;

wherein X a , X b , X c , X d , X e and X f are independently of each other oxygen or sulfur; and wherein

R a is hydrogen, C 1 -C 18 alkyl, C 2 -C 18 alkenyl, C 2 -C 18 alkynyl, C 1 -C 10 haloalkyl, C 1 -C 10 cyanoalkyl, C 1 -C 10 nitroalkyl, C 1 -C 10 aminoalkyl, C 1 -C 5 alkylaminoC 1 -C 5 alkyl, C 2 -C 8 dialkylaminoC 1 -C 5 alkyl, C 3 -C 7 cycloalkylC 1 -C 5 alkyl, C 1 -C 5 alkoxyC 1 -C 5 alkyl, C 3 -C 5 alkenyloxyC 1 -C 5 alkyl, C 3 -C 5 alkynyloxyC 1 -C 5 alkyl, C 1 -C 5 alkylthioC 1 -C 5 alkyl, C 1 -C 5 alkylsulfinylC 1 -C 5 alkyl, C 1 -C 5 alkylsulfonylC 1 -C 5 alkyl, C 2 -C 8 alkylideneaminoxyC 1 -C 5 alkyl, C 1 -C 5 alkylcarbonylC 1 -C 5 alkyl, C 1 -C 5 alkoxycarbonylC 1 -C 5 alkyl, aminocarbonylC 1 -C 5 alkyl, C 1 -C 5 alkylaminocarbonylC 1 -C 5 alkyl, C 2 -C 8 dialkylaminocarbonylC 1 -C 5 alkyl, C 1 -C 5 alkylcarbonylaminoC 1 -C 5 alkyl, N—C 1 -C 5 alkylcarbonyl-N—C 1 -C 5 alkylaminoC 1 -C 5 alkyl, C 3 -C 6 trialkylsilylC 1 -C 5 alkyl, phenylC 1 -C 5 alkyl (wherein the phenyl is optionally substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl, C 1 -C 3 alkylsulfonyl, halogen, cyano, or by nitro), heteroarylC 1 -C 5 alkyl (wherein the heteroaryl is optionally substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl, C 1 -C 3 alkylsulfonyl, halogen, cyano, or by nitro), C 2 -C 5 haloalkenyl, C 3 -C 8 cycloalkyl; phenyl or phenyl substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or nitro; or heteroaryl or heteroaryl substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or nitro;

R b is C 1 -C 18 alkyl, C 3 -C 18 alkenyl, C 3 -C 18 alkynyl, C 2 -C 10 haloalkyl, C 1 -C 10 cyanoalkyl, C 1 -C 10 nitroalkyl, C 2 -C 10 aminoalkyl, C 1 -C 5 alkylaminoC 1 -C 5 alkyl, C 2 -C 8 dialkylaminoC 1 -C 5 alkyl, C 3 -C 7 cycloalkylC 1 -C 5 alkyl, C 1 -C 5 alkoxyC 1 -C 5 alkyl, C 3 -C 5 alkenyloxyC 1 -C 5 alkyl, C 3 -C 5 alkynyloxyC 1 -C 5 alkyl, C 1 -C 5 alkylthioC 1 -C 5 alkyl, C 1 -C 5 alkylsulfinylC 1 -C 5 alkyl, C 1 -C 5 alkylsulfonylC 1 -C 5 alkyl, C 2 -C 8 alkylideneaminoxyC 1 -C 5 alkyl, C 1 -C 5 alkylcarbonylC 1 -C 5 alkyl, C 1 -C 5 alkoxycarbonylC 1 -C 5 alkyl, aminocarbonylC 1 -C 5 alkyl, C 1 -C 5 alkylaminocarbonylC 1 -C 5 alkyl, C 2 -C 8 dialkylaminocarbonylC 1 -C 5 alkyl, C 1 -C 5 alkylcarbonylaminoC 1 -C 5 alkyl, N—C 1 -C 5 alkylcarbonyl-N—C 1 -C 5 alkylaminoC 1 -C 5 alkyl, C 3 -C 6 trialkylsilylC 1 -C 5 alkyl, phenylC 1 -C 5 alkyl (wherein the phenyl is optionally substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl, C 1 -C 3 alkylsulfonyl, halogen, cyano, or by nitro), heteroarylC 1 -C 5 alkyl (wherein the heteroaryl is optionally substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl, C 1 -C 3 alkylsulfonyl, halogen, cyano, or by nitro), C 3 -C 5 haloalkenyl, C 3 -C 8 cycloalkyl; phenyl or phenyl substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or nitro; or heteroaryl or heteroaryl substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or nitro; and

R c and R d are each independently of each other hydrogen, C 1 -C 10 alkyl, C 3 -C 10 alkenyl, C 3 -C 10 alkynyl, C 2 -C 10 haloalkyl, C 1 -C 10 cyanoalkyl, C 1 -C 10 nitroalkyl, C 1 -C 10 aminoalkyl, C 1 -C 5 alkylaminoC 1 -C 5 alkyl, C 2 -C 8 dialkylaminoC 1 -C 5 alkyl, C 3 -C 7 cycloalkylC 1 -C 5 alkyl, C 1 -C 5 alkoxyC 1 -C 5 alkyl, C 3 -C 5 alkyenyloxyC 1 -C 5 alkyl, C 3 -C 5 alkynyloxyC 1 -C 5 alkyl, C 1 -C 5 alkylthioC 1 -C 5 alkyl, C 1 -C 5 alkylsulfinylC 1 -C 5 alkyl, C 1 -C 5 alkylsulfonylC 1 -C 5 alkyl, C 2 -C 8 alkylideneaminoxyC 1 -C 5 alkyl, C 1 -C 5 alkylcarbonylC 1 -C 5 alkyl, C 1 -C 5 alkoxycarbonylC 1 -C 5 alkyl, aminicarbonylC 1 -C 5 alkyl, C 1 -C 5 alkylaminocarbonylC 1 -C 5 alkyl, C 2 -C 8 dialkylaminocarbonylC 1 -C 5 alkyl, C 1 -C 5 alkylcarbonylaminoC 1 -C 5 alkyl, N—C 1 -C 5 alkylcarbonyl-N—C 2 -C 5 alkylaminoalkyl, C 3 -C 6 trialkylsilylC 1 -C 5 alkyl, phenylC 1 -C 5 alkyl (wherein the phenyl is optionally substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 5 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl, C 1 -C 3 alkylsulfonyl, halogen, cyano, or by nitro), heteroarylC 1 -C 5 alkyl (wherein the heteroaryl is optionally substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl, C 1 -C 3 alkylsulfonyl, halogen, cyano, or by nitro), C 2 -C 5 haloalkenyl, C 3 -C 8 cycloalkyl; phenyl or phenyl substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or nitro; heteroaryl or heteroaryl substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or nitro; heteroarylamino or heteroarylamino substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or nitro; diheteroarylamino or diheteroarylamino substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or nitro; phenylamino or phenylamino substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or by nitro; diphenylamino or diphenylamino substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or by nitro; or C 3 -C 7 cycloalkylamino, di-C 3 -C 7 cycloalkylamino or C 3 -C 7 cycloalkoxy;

or R c and R d may join together to form a 3-7 membered ring, optionally containing one heteroatom selected from O or S; and

R e is C 1 -C 10 alkyl, C 2 -C 10 alkenyl, C 2 -C 10 alkynyl,C 1 -C 10 haloalkyl, C 1 -C 10 cyanoalkyl, C 1 -C 10 nitroalkyl, C 1 -C 10 aminoalkyl, C 1 -C 5 alkylaminoC 1 -C 5 alkyl, C 2 -C 8 dialkylaminoC 1 -C 5 alkyl, C 3 -C 7 cycloalkylC 1 -C 5 alkyl, C 1 -C 5 alkoxyC 1 -C 5 alkyl, C 3 -C 5 alkenyloxyC 1 -C 5 alkyl, C 3 -C 5 alkynyloxyC 1 -C 5 alkyl, C 1 -C 5 alkylthioC 1 -C 5 alkyl, C 1 -C 5 alkylsulfinylC 1 -C 5 alkyl, C 1 -C 5 alkylsulfonylC 1 -C 5 alkyl, C 2 -C 8 alkylideneaminoxyC 1 -C 5 alkyl, C 1 -C 5 alkylcarbonylC 1 -C 5 alkyl, C 1 -C 5 alkoxycarbonylC 1 -C 5 alkyl, aminocarbonylC 1 -C 5 alkyl, C 1 -C 5 alkylaminocarbonylC 1 -C 5 alkyl, C 2 -C 8 dialkylaminocarbonylC 1 -C 5 alkyl, C 1 -C 5 alkylcarbonylaminoC 1 -C 5 alkyl, N—C 1 -C 5 alkylcarbonyl-N—C 1 -C 5 alkylaminoC 1 -C 5 alkyl, C 3 -C 6 trialkylsilylC 1 -C 5 alkyl, phenylC 1 -C 5 alkyl (wherein the phenyl is optionally substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl, C 1 -C 3 alkylsulfonyl, halogen, cyano, or by nitro), heteroarylC 1 -C 5 alkyl (wherein the heteroaryl is optionally substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl, C 1 -C 3 alkylsulfonyl, halogen, cyano, or by nitro), C 2 -C 5 haloalkenyl, C 3 -C 8 cycloalkyl; phenyl or phenyl substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or nitro; heteroaryl or heteroaryl substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or by nitro; heteroarylamino or heteroarylamino substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or by nitro; diheteroarylamino or diheteroarylamino substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or nitro; phenylamino or phenylamino substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or nitro; diphenylamino or diphenylamino substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or nitro; or C 3 -C 7 cycloalkylamino, diC 3 -C 7 cycloalkylamino, C 3 -C 7 cycloalkoxy, C 1 -C 10 alkoxy, C 1 -C 10 haloalkoxy, C 1 -C 5 alkylamino or C 2 -C 8 dialkylamino;

R f and R g are each independently of each other C 1 -C 10 alkyl, C 2 -C 10 alkenyl, C 2 -C 10 alkynyl, C 1 -C 10 alkoxy, C 1 -C 10 haloalkyl, C 1 -C 10 cyanoalkyl, C 1 -C 10 nitroalkyl, C 1 -C 10 aminoalkyl, C 1 -C 5 alkylaminoC 1 -C 5 alkyl, C 2 -C 8 dialkylaminoC 1 -C 5 alkyl, C 3 -C 7 cycloalkylC 1 -C 5 alkyl, C 1 -C 5 alkoxyC 1 -C 5 alkyl, C 3 -C 5 alkenyloxyC 1 -C 5 alkyl, C 3 -C 5 alkynyloxyC 1 -C 5 alkyl, C 1 -C 5 alkylthioC 1 -C 5 alkyl, C 1 -C 5 alkylsulfinylC 1 -C 5 alkyl, C 1 -C 5 alkylsulfonylC 1 -C 5 alkyl, C 2 -C 8 alkylideneaminoxyC 1 -C 5 alkyl, C 1 -C 5 alkylcarbonylC 1 -C 5 alkyl, C 1 -C 5 alkoxycarbonylC 1 -C 5 alkyl, aminocarbonylC 1 -C 5 alkyl, C 1 -C 5 alkylaminocarbonylC 1 -C 5 alkyl, C 2 -C 8 dialkylaminocarbonylC 1 -C 5 alkyl, C 1 -C 5 alkylcarbonylaminoC 1 -C 5 alkyl, N—C 1 -C 5 alkylcarbonyl-N—C 2 -C 5 alkylaminoalkyl, C 3 -C 6 trialkylsilylC 1 -C 5 alkyl, phenylC 1 -C 5 alkyl (wherein the phenyl is optionally be substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 5 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl, C 1 -C 3 alkylsulfonyl, halogen, cyano, or by nitro), heteroarylC 1 -C 5 alkyl (wherein the heteroaryl is optionally substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl, C 1 -C 3 alkylsulfonyl, halogen, cyano, or by nitro), C 2 -C 5 haloalkenyl, C 3 -C 8 cycloalkyl; phenyl or phenyl substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or nitro; heteroaryl or heteroaryl substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or by nitro; heteroarylamino or heteroarylamino substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 haloalkoxy, halogen, cyano or by nitro; diheteroarylamino or diheteroarylamino substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or nitro; phenylamino or phenylamino substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or nitro; diphenylamino or diphenylamino substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or nitro; or C 3 -C 7 cycloalkylamino, diC 3 -C 7 cycloalkylamino, C 3 -C 7 cycloalkoxy, C 1 -C 10 haloalkoxy, C 1 -C 5 alkylamino or C 2 -C 8 dialkylamino; or benzyloxy or phenoxy, wherein the benzyl and phenyl groups may in turn be substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or nitro; and

R h is C 1 -C 10 alkyl, C 3 -C 10 alkenyl, C 3 -C 10 alkynyl, C 1 -C 10 haloalkyl, C 1 -C 10 cyanoalkyl, C 1 -C 10 nitroalkyl, C 2 -C 10 aminoalkyl, C 1 -C 5 alkylaminoC 1 -C 5 alkyl, C 2 -C 8 dialkylaminoC 1 -C 5 alkyl, C 3 -C 7 cycloalkylC 1 -C 5 alkyl, C 1 -C 5 alkoxyC 1 -C 5 alkyl, C 3 -C 5 alkenyloxyC 1 -C 5 alkyl, C 3 -C 5 alkynyloxyC 1 -C 5 alkyl, C 1 -C 5 alkylthioC 1 -C 5 alkyl, C 1 -C 5 alkylsulfinylC 1 -C 5 alkyl, C 1 -C 5 alkylsulfonylC 1 -C 5 alkyl, C 2 -C 8 alkylideneaminoxyC 1 -C 5 alkyl, C 1 -C 5 alkylcarbonylC 1 -C 5 alkyl, C 1 -C 5 alkoxycarbonylC 1 -C 5 alkyl, aminocarbonylC 1 -C 5 alkyl, C 1 -C 5 alkylaminocarbonylC 1 -C 5 alkyl, C 2 -C 8 dialkylaminocarbonylC 1 -C 5 alkyl, C 1 -C 5 alkylcarbonylaminoC 1 -C 5 alkyl, N—C 1 -C 5 alkylcarbonyl-N—C 1 -C 5 alkylaminoC 1 -C 5 alkyl, C 3 -C 6 trialkylsilylC 1 -C 5 alkyl, phenylC 1 -C 5 alkyl (wherein the phenyl is optionally substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl, C 1 -C 3 alkylsulfonyl, halogen, cyano or by nitro), heteroarylC 1 -C 5 alkyl (wherein the heteroaryl is optionally substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl, C 1 -C 3 alkylsulfonyl, halogen, cyano or by nitro), phenoxyC 1 -C 5 alkyl (wherein the phenyl is optionally substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl, C 1 -C 3 alkylsulfonyl, halogen, cyano or by nitro), heteroaryloxyC 1 -C 5 alkyl (wherein the heteroaryl is optionally substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl, C 1 -C 3 alkylsulfonyl, halogen, cyano or by nitro), C 3 -C 5 haloalkenyl, C 3 -C 8 cycloalkyl; phenyl or phenyl substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen or by nitro; or heteroaryl or heteroaryl substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, halogen, cyano or by nitro.

2. A compound according to claim 1 , wherein R 1 is methyl, ethyl, vinyl, ethynyl, methoxy or halogen.

3. A compound according to claim 2 , wherein R 1 is methyl, ethyl, methoxy or halogen.

4. A compound according to claim 3 , wherein R 1 is methyl or ethyl.

5. A compound according to claim 1 , wherein R 2 is hydrogen, halogen, methyl, ethyl, phenyl or phenyl substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, cyano, nitro, halogen, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl or C 1 -C 3 alkylsulfonyl.

6. A compound according to claim 5 , wherein R 2 is methyl.

7. A compound according to claim 1 , wherein R 3 is hydrogen, halogen, methyl, ethyl, phenyl or phenyl substituted by C 1 -C 3 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, cyano, nitro, halogen, C 1 -C 3 alkylthio, C 1 -C 3 alkylsulfinyl or C 1 -C 3 alkylsulfonyl.

8. A compound according to claim 1 , wherein R 2 and R 3 idependently of each other are hydrogen, methyl, ethyl, halogen, optionally substituted phenyl or optionally substituted heteroaryl.

9. A compound according to claim 1 , wherein R 4 is hydrogen, methyl, ethyl, vinyl or ethynyl.

10. A compound according to claim 9 , wherein R 4 is hydrogen, methyl or ethyl.

11. A compound according to claim 1 , wherein R 5 is hydrogen.

12. A compound according to claim 1 , wherein R 6 and R 7 are each hydrogen.

13. A compound according to claim 1 , wherein R 6 and R 7 are methyl or ethyl.

14. A compound according to claim 1 , wherein R 6 is hydrogen and R 7 is methyl or ethyl.

15. A compound according to claim 1 , wherein X denotes S(O) or S(O) 2 ; and R 8 is C 1 -C 18 alkyl, C 3 -C 7 cycloalkyl, C 3 -C 7 cycloalkyl substituted by methyl or ethyl, C 1 -C 6 alkoxyC 1 -C 12 alkyl, C 1 -C 6 alkylthioC 1 -C 12 alkyl, C 3 -C 18 alkenyl, C 3 -C 18 alkynyl or C 3 -C 18 alkynyl substituted by halogen.

16. A compound according to claim 15 , wherein R 8 is C 1 -C 6 alkyl or C 3 -C 7 cycloalkyl.

17. A compound according to claim 16 , wherein R 8 is methyl, ethyl or propyl.

18. A compound according to claim 1 , wherein X denotes O or S; and R 8 is methyl, ethyl, propyl, butyl, pentyl or hexyl, C 7 -C 18 alkyl, C 3 -C 7 cycloalkyl, C 3 -C 7 cycloalkyl substituted by methyl or ethyl, C 1 -C 6 alkoxyC 1 -C 12 alkyl, C 1 -C 6 alkylthioC 1 -C 12 alkyl, C 3 -C 18 alkenyl, C 3 -C 18 alkynyl or C 3 -C 18 alkynyl substituted by halogen.

19. A compound according to claim 18 , wherein R 8 is methyl, ethyl or propyl.

20. A compound according to claim 19 , wherein R 8 is ethyl or propyl.

21. A compound according to claim 1 , wherein

X denotes S(O) or S(O) 2 ;

R 8 is C 1 -C 18 alkyl, C 3 -C 7 cycloalkyl, C 3 -C 7 cycloalkyl substituted by methyl or ethyl, C 1 -C 6 alkoxyC 1 -C 12 alkyl, C 1 -C 6 alkylthioC 1 -C 12 alkyl, C 3 -C 18 alkenyl, C 3 -C 18 alkynyl or C 3 -C 18 alkynyl substituted by halogen; and

R 6 and R 7 are methyl or ethyl, or R 6 is hydrogen and R 7 is methyl or ethyl.

22. A compound according to claim 1 , wherein R 8 —X—[CR 6 R 7 ] 1 -is different from CH 3 OCH 2 - and CH 3 SCH 2 —.

23. A compound according to claim 1 , wherein G is C(X a )—R a or C(X b )—X c —R b .

24. A compound according to claim 1 , wherein G is hydrogen, an alkali metal or alkaline earth metal.

25. A compound according to claim 24 , wherein G is hydrogen.

26. A compound according to claim 1 , wherein n is 1 or 2.

27. A compound according to claim 1 , wherein R 5 , when n denotes 1 or 2, and R 8 together form a C 2 -C 5 alkylene chain.

28. A compound according to claim 1 , wherein R 5 , when n denotes 1, and R 8 together form a propylene chain and R 6 and R 7 are each hydrogen.

29. A compound according to claim 1 , wherein R 5 , when n denotes 1 or 2, and R 8 together form an ethylene chain and R 6 and R 7 are each hydrogen.

30. A compound according to claim 29 , wherein n denotes 2.

31. A compound according to claim 1 , wherein R 5 , when n denotes 1 or 2, and R 8 together form an ethylene chain and R 6 and R 7 are each hydrogen and X is O.

32. A compound according to claim 1 , wherein R 5 , when n denotes 1 or 2, and R 8 together form an ethylene chain and R 6 and R 7 are each hydrogen and X is S(O) or S(O) 2 .

33. A compound according to claim 1 , wherein R 1 , R 2 and R 4 are independently of each other methyl or ethyl and R 3 is hydrogen.

34. A compound according to claim 1 , wherein R 1 is methyl or ethyl, R 2 is hydrogen, R 3 is phenyl or phenyl substituted by C 1 -C 4 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, cyano, nitro or halogen, or heteroaryl or heteroaryl substituted by C 1 -C 4 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, cyano, nitro or halogen.

35. A compound according to claim 1 , wherein R 1 is methyl or ethyl, R 2 is phenyl or phenyl substituted by C 1 -C 4 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, cyano, nitro or halogen, or heteroaryl or heteroaryl substituted by C 1 -C 4 alkyl, C 1 -C 3 haloalkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkoxy, cyano, nitro or halogen, R 3 is hydrogen and R 4 is hydrogen, methyl or ethyl.

36. A process for the preparation of a compound of formula (I) according to claim 1 , wherein G is hydrogen, which comprises reacting a compound of the formula (Y)

wherein R 5 , R 6 , R 7 , R 8 and X and n have the meanings assigned to them in claim 1 , and Ar is an optionally substituted aromatic ring with an aryl boronic acid of the formula (Z)

wherein R 1 , R 2 , R 3 and R 4 have the meanings assigned to them in claim 1 , in the presence of a palladium catalyst, a base and a solvent.

37. A process for the preparation of a compound of formula (I) according to claim 1 , wherein G is hydrogen, which comprises cyclisation of the compound of the formula (B)

wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 and X and n have the meanings assigned to them in claim 1 and R is alkyl, under acidic or basic conditions.

38. A process for the preparation of a compound of formula (I) according to claim 1 , wherein G is hydrogen, which comprises cyclisation of the compound of the formula (B)

wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 and X and n have the meanings assigned to them in claim 1 and R is hydrogen, under acidic conditions.

39. A process for the preparation of a compound of formula (I) according to claim 1 , wherein G is an alkyl, acyl, phosphoryl or sulfonyl group, which comprises treating the compound of the formula (A)

wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 and X and n have the meanings assigned to them in claim 1 with a compound of the formula G-Z, wherein G represents the alkyl, acyl, phosphoryl or sulfonyl group to be incorporated and Z is a suitable nucleofuge, in the presence of at least one equivalent of a base.

40. A process for the preparation of a compound of formula (1) according to claim 1 , which comprises treating a compound of formula (JJ)

wherein G is C 1 -C 4 alkyl, Hal is chlorine, bromine or iodine and R 5 , R 6 , R 7 and R 8 have the meanings assigned to them in claim 1 with an aryl boronic acid of formula (Z)

wherein R 1 , R 2 , R 3 and R 4 have the meanings assigned to them in claim 1 , in the presence of a base, a solvent and a palladium catalyst.

41. A method of controlling grasses and weeds in crops of useful plants, which comprises applying a herbicidally effective amount of a compound of formula (I) as defined in claim 1 , or of a composition comprising such a compound, to the plants or to the locus thereof.

42. A herbicidal composition, which, in addition to comprising formulation adjuvants, comprises a herbicidally effective amount of a compound of formula (I) as defined in claim 1 .

43. A composition according to claim 42 , which, in addition to comprising the compound of formula (I), comprises a further herbicide as mixing partner.

44. A composition according to claim 42 , which, in addition to comprising the compound of formula (I), comprises a safener.

45. A composition according to claim 42 , which, in addition to comprising the compound of formula (I), comprises a further herbicide as mixing partner and a safener.

46. A compound according to claim 1 , wherein when G is a latentiating group then G is a group -C(X a )—R a or -C(X b )—X c —R b , and the meanings of X a , R a , X b , X c and R b are as defined in claim 1 .

47. A method as claimed in claim 41 , in which a herbicidally effective amount of the composition comprising the compound of formula (I) as defined in claim 1 is applied to the plants or to the locus thereof, and wherein the crops of useful plants are cereals, cotton, soybeans, sugar beet, sugar cane, plantation crops, rape, maize or rice.