Herbicidal compounds

1. A compound of formula (I)

wherein

X is selected from S and O;

A is

R b is selected from hydrogen, formyl, hydroxyl, halogen, nitro, cyano, C 1 -C 8 alkyl, C 1 -C 6 cyanoalkyl, C 1 -C 6 haloalkyl, C 1 -C 6 hydroxyalkyl, C 1 -C 6 alkylthio, C 1 -C 6 alkoxy, C 1 -C 6 alkoxy C 1 -C 6 alkyl, C 1 -C 6 alkylthio C 1 -C 6 alkyl, C 1 -C 6 cyanoalkoxy, C 1 -C 6 haloalkoxy, C 1 -C 6 alkoxy C 1 -C 6 alkoxy, C 2 -C 8 alkenyl, C 2 -C 8 alkynyl, C 2 -C 6 cyanoalkenyl, C 2 -C 6 cyanoalkynyl, C 2 -C 6 alkenyloxy, C 2 -C 6 alkynyloxy, C 2 -C 6 haloalkenyl, C 2 -C 6 haloalkynyl, C 2 -C 6 haloalkenyloxy, C 2 -C 6 haloalkynyloxy, C 1 -C 6 alkoxy C 2 -C 6 alkenyl, C 1 -C 6 alkoxy C 2 -C 6 alkynyl, C 1 -C 6 alkylsulfinyl, C 1 -C 6 alkylsulfonyl, C 1 -C 6 haloalkylthio, C 1 -C 6 haloalkylsulfinyl, C 1 -C 6 haloalkylsulfonyl, C 1 -C 6 alkylsulfonyloxy, C 1 -C 6 alkylcarbonyl, C 1 -C 6 haloalkylcarbonyl, C 2 -C 6 alkenylcarbonyl, C 2 -C 6 alkynylcarbonyl, C 2 -C 6 haloalkenylcarbonyl, C 2 -C 6 haloalkynylcarbonyl, tri C 1 -C 6 alkylsilyl C 2 -C 6 alkynyl, R 5 R 6 NC(O)—, a group R 5 R 6 N—, a group R 5 C(O)N(R 6 )—, a group R 5 S(O 2 )N(R 6 )—, a group R 5 R 6 NSO 2 —, a group R 5 R 6 NC(O) C 1 -C 6 alkyl, a C 6 -C 10 aryloxy group optionally substituted by from 1 to 3 groups independently selected from halogen, nitro, cyano, C 1 -C 3 alkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkyl and C 1 -C 3 haloalkoxy, a C 6 -C 10 aryl C 1 -C 3 alkyl group optionally substituted by from 1 to 3 groups independently selected from halogen, nitro, cyano, C 1 -C 3 alkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkyl and C 1 -C 3 haloalkoxy, a C 6 -C 10 benzyloxy group optionally substituted by from 1 to 3 groups independently selected from halogen, nitro, cyano, C 1 -C 3 alkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkyl and C 1 -C 3 haloalkoxy, a C 3 -C 6 heterocyclyl group optionally substituted by from 1 to 3 groups independently selected from C 1 -C 4 alkyl, a C 3 -C 6 cycloalkyl group optionally substituted with from 1 to 3 groups independently selected from halogen, cyano, C 1 -C 6 alkoxy and C 1 -C 6 alkyl and a C 3 -C 7 cycloalkenyl group optionally substituted with from 1 to 3 groups independently selected from halogen, cyano, C 1 -C 6 alkoxy and C 1 -C 6 alkyl, or R b and R c together with the carbon atoms to which they are attached form a 3-7 membered saturated or partially unsaturated ring optionally comprising from 1 to 3 heteroatoms independently selected from S, O and N and optionally substituted with from 1 to 3 groups independently selected from halogen, C 1 -C 6 alkyl and C 1 -C 6 haloalkyl;

R c is selected from hydrogen, halogen, cyano, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 1 -C 6 alkylthio, a group R 5 R 6 NC(O)— or R c and R b together with the carbon atoms to which they are attached form a 3-7 membered saturated or partially unsaturated ring optionally comprising from 1 to 3 heteroatoms independently selected from S, O and N and optionally substituted with from 1 to 3 groups independently selected from halogen, C 1 -C 6 alkyl and C 1 -C 6 haloalkyl;

R 1 is selected from hydrogen, C 1 -C 6 alkyl optionally substituted with NR 10 R 11 , C 1 -C 3 haloalkyl, C 1 -C 6 alkoxy and C 2 -C 6 alkynyl; wherein R 10 and R 11 are independently selected from hydrogen, C 1 -C 6 alkyl and C 1 -C 6 haloalkyl;

R 2 is selected from hydrogen, hydroxyl, halogen, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 1 -C 6 alkoxy, C 1 -C 6 haloalkyl, C 1 -C 6 haloalkoxy, C 1 -C 6 alkoxy C 1 -C 6 alkyl, and the group —NR 12 R 13 , wherein R 12 and R 13 are independently selected from hydrogen and C 1 -C 6 alkyl;

or R 1 and R 2 together with the nitrogen and carbon atoms to which they are attached form a 3-7 membered saturated or partially unsaturated ring optionally comprising from 1 to 3 heteroatoms independently selected from S, O and N and optionally substituted with from 1 to 3 groups independently selected from hydroxyl, ═O, C 1 -C 6 alkyl and C 1 -C 6 haloalkyl;

R 3 is selected from halogen, hydroxyl, —NR 14 R 15 , or any one of the following groups:

R 5 and R 6 are independently selected from hydrogen, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 1 -C 6 alkoxy, C 1 -C 6 cyanoalkyl, or R 5 and R 6 together with the carbon atoms to which they are attached form a 3-6 membered saturated or partially unsaturated ring optionally comprising from 1 to 3 heteroatoms independently selected from S, O and N and optionally substituted with from 1 to 3 groups independently selected from halogen and C 1 -C 6 alkyl;

R 7 and R 8 are independently selected from hydrogen, C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, a C 5 -C 10 heteroaryl group which can be mono- or bicyclic comprising from 1 to 4 heteroatoms independently selected from N, O and S and optionally substituted with 1 to 3 groups independently selected from halogen, C 1 -C 3 alkyl, C 1 -C 3 haloalkyl and C 1 -C 3 alkoxy, a C 6 -C 10 aryl group optionally substituted with 1 to 3 groups independently selected from halogen, nitro, cyano, C 1 -C 3 alkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkyl and C 1 -C 3 haloalkoxy, or R 7 and R 8 together with the atoms to which they are attached form a 3-6 membered saturated or partially unsaturated ring optionally comprising from 1 to 3 heteroatoms independently selected from S, O and N and optionally substituted with from 1 to 3 groups independently selected from halogen or C 1 -C 6 alkyl;

R 9 is selected from C 1 -C 6 alkyl or benzyl optionally substituted with 1 to 3 groups independently selected from halogen, nitro, cyano, C 1 -C 3 alkyl, C 1 -C 3 alkoxy, C 1 -C 3 haloalkyl and C 1 -C 3 haloalkoxy;

R 14 and R 15 are independently selected from hydrogen, C 1 -C 20 alkyl, C 1 -C 20 haloalkyl, C 2 -C 20 alkenyl, C 2 -C 20 alkynyl, or R 14 and R 15 together with the carbon atoms to which they are attached form a 3-6 membered saturated or partially unsaturated ring optionally comprising from 1 to 3 heteroatoms independently selected from S, O and N and optionally substituted with from 1 to 3 groups independently selected from halogen and C 1 -C 6 alkyl;

or an N-oxide or salt form thereof.

2. The compound of claim 1 , wherein X is O.

3. The compound of claim 1 , wherein R b is selected from C 1 -C 6 alkyl, C 1 -C 6 hydroxyalkyl, C 1 -C 6 haloalkyl, C 1 -C 6 cyanoalkyl and C 1 -C 6 alkoxy C 1 -C 6 alkyl.

4. The compound of claim 3 , wherein R c is selected from hydrogen, halogen, cyano, C 1 -C 6 alkyl and C 1 -C 6 haloalkyl.

5. The compound of claim 1 , wherein R 1 is selected from C 1 -C 3 alkyl, C 1 -C 3 alkoxy, and C 1 -C 3 haloalkyl.

6. The compound of claim 1 , wherein R 2 is selected from hydrogen, C 1 -C 3 alkyl, C 1 -C 3 alkoxy, and C 1 -C 3 alkoxy-C 1 -C 3 alkyl.

7. The compound of claim 1 , wherein R 1 and R 2 together with the nitrogen atoms to which they are attached form a 3-7 membered saturated or partially unsaturated ring optionally comprising from 1 to 3 heteroatoms independently selected from S, O, and N and optionally substituted with from 1 to 3 groups independently selected from hydroxyl, ═O, C 1 -C 6 alkyl, and C 1 -C 6 haloalkyl.

8. The compound of claim 1 , wherein R 3 is selected from halogen, hydroxyl, —NR 14 R 15 or any of the following groups

9. A herbicidal composition comprising a compound of formula (I) as defined in claim 1 together with at least one agriculturally acceptable adjuvant or diluent.

10. A composition according to claim 9 which further comprises an additional herbicide in addition to the compound of formula (I).

11. A composition according to claim 9 which further comprises a safener.

12. A method of controlling weeds in crops of useful plants, comprising applying to said weeds or to the locus of said weeds, or to said useful plants or to the locus of said useful plants, an effective amount of a compound of formula (I) as defined in claim 1 .