Pyrazine-4Carbamate or -Urea Derivatives As Herbicides

A compound of formula (I)

• or a salt thereof,
• wherein:
• X1 is N or CR1;
• R1 is selected from the group consisting of hydrogen, halogen, cyano, C1-C6alkyl, C3-C6cycloalkyl, C2-C6alkenyl, C2-C6alkynyl, C1-C6alkoxy, —C(O)OC1-C6alkyl, —S(O)pC1-C6alkyl, NR6R7, C1-C6haloalkoxy and C1-C6haloalkyl;
• R2 is selected from the group consisting of halogen, cyano, nitro, C1-C6alkyl, C1- C6haloalkyl, C2-C6alkenyl, C2-C6alkynyl, trimethylsilylC2-C6alkynyl-, C3-C6cycloalkyl, C5-C6cycloalkenyl, —C(O)OC1-C6alkyl, —S(O)p(C1-C6alkyl), C1-C6alkoxy, C1-C6haloalkoxy, —O—(CRaRb)qR10, or phenyl;
• R3 is —C(O)R9;
• R4 is selected from the group consisting of hydrogen, C1-C6alkyl, C1-C6haloalkyl, C2-C6alkenyl, C2-C6alkynyl, CralkoxyCsalkyl, -CralkoxyCshaloalkyl, CralkoxyCsthioalkyl, —C(O)R9 and —(CRaRb)qR5;
• each Ra is independently hydrogen or C1-C2 alkyl;
• each Rb is independently hydrogen or C1-C2 alkyl;
• R5 is —C(O)OC1-C6alkyl, -C3-C6cycloalkyl, cyano, —NR6R7, —C(O)NRaRb, —S(O)p(R11)n, -aryl or-heteroaryl wherein said aryl and heteroaryl are optionally substituted by 1 to 3 independent R8;
• R6 and R7 are independently selected from the group consisting of hydrogen, C1-C6alkyl and —C(O)OC1-C6alkyl;
• each R8 is independently selected from the group consisting of halogen, C1-C6 alkyl and C1-C6alkoxy-, C1-C6 haloalkyl, C1-C6 haloalkoxy-, cyano and S(O)p(C1-C6alkyl);
• each R9 is independently selected from the group consisting of hydrogen, C1-C6alkyl, CralkoxyCsalkyl, C1-C6haloalkyl, CralkoxyCshaloalkyl, C2-C6alkenyl, C2-C6alkynyl, and —(CRaRb)qR10;
• or R4 and R9 together with the atoms to which they are joined form a 5-7 membered ring system containing from 1 to 3 heteroatoms, wherein at least one heteratom is N, and any additional heteroatom is independently selected from S in the form of S(O)p, O and N;
• each R10 is independently —C(O)ORc, —C(O)Rc, —C3-C6cycloalkyl, or an -aryl, -aryloxy, -heteroaryl, -heteroaryloxy or -heterocyclyl ring, wherein said ring is optionally substituted by 1 to 3 independent R8;
• Rc is hydrogen or C1-C4alkyl;
• each n is independently 0 or 1;
• p is 0, 1, or 2;
• each q is independently 0, 1, 2, 3, 4, 5 or 6;
• r is 1, 2, 3, 4, or 5, s is 1, 2, 3, 4, or 5, and the sum of r+s is less than or equal to 6;
• and
• R11 is C1-C6alkyl.