Substituted Pyridopyrazines with a Herbicidal Action

A compound of formula (I)

• in which
• R1 is O—RA, or S(O)n—RA or OS(O)n—RA;
• RA is hydrogen, C1-C4-alkyl, Z—C3-C6-cycloalkyl, C1-C4-haloalkyl, C2-C6-alkenyl, Z—C3-C6-cycloalkenyl, C2-C6-alkynyl, Z-(tri-C1-C4-alkyl)silyl, Z—C(═O)—Ra, Z—P(═O)(Ra)2, a 3- to 7-membered monocyclic or 9- or 10-membered bicyclic saturated, unsaturated or aromatic heterocycle which contains 1, 2, 3 or 4 heteroatoms selected from the group consisting of O, N and S, which may be partially or fully substituted by groups Ra and/or Rb and which is attached via carbon or nitrogen,
• Ra is hydrogen, OH, C1-C8-alkyl, C1-C4-haloalkyl, Z—C3-C6-cycloalkyl, C2-C8-alkenyl, Z—C5-C6-cycloalkenyl, C2-C8-alkynyl, Z—C1-C6-alkoxy,
• Z—C1-C4-haloalkoxy, Z—C3-C8-alkenyloxy, Z—C3-C8-alkynyloxy, NRiRii, C1-C6-alkylsulfonyl, Z-(tri-C1-C4-alkyl)silyl, Z-phenyl, Z-phenoxy, Z-phenylamino or a 5- or 6-membered monocyclic or 9- or 10-membered bicyclic heterocycle which contains 1, 2, 3 or 4 heteroatoms selected from the group consisting of O, N and S, wherein the cyclic groups are unsubstituted or substituted by 1, 2, 3 or 4 groups Rb;
• Ri, Rii independently of one another are hydrogen, C1-C8-alkyl, C1-C4-haloalkyl, C3-C8-alkenyl, C3-C8-alkynyl, Z—C3-C6-cycloalkyl, Z—C1-C8-alkoxy, or Z—C1-C8-haloalkoxy;
• or
• Ri and Rii together with the nitrogen atom to which they are attached may form a 5- or 6-membered monocyclic or 9- or 10-membered bicyclic heterocycle which contains 1, 2, 3 or 4 heteroatoms selected from the group consisting of O, N and S;
• Z is a covalent bond or C1-C4-alkylene;
• n is 0, 1 or 2;
• R2 is phenyl, naphthyl or a 5- or 6-membered monocyclic or 9- or 10-membered bicyclic aromatic heterocycle which contains 1, 2, 3 or 4 heteroatoms selected from the group consisting of O, N and S, wherein the cyclic groups are unsubstituted or substituted by 1, 2, 3 or 4 groups Rb;
• Rb independently of one another are Z—CN, Z—OH, Z—NO2, Z-halogen, C1-C8-alkyl, C1-C4-haloalkyl, C2-C8-alkenyl, C2-C8-alkynyl, Z—C1-C8-alkoxy, Z—C1-C8-haloalkoxy, Z—C3-C10-cycloalkyl, O—Z—C3-C10-cycloalkyl, Z—C(═O)—Ra, NRiRii, Z-(tri-C1-C4-alkyl)silyl, Z-phenyl and S(O)nRbb,
• where Rbb is C1-C8-alkyl or C1-C6-haloalkyl and
• n is 0, 1 or 2;
• Rb1, Rb2 are one of the groups mentioned for Rb;
• or
• one of Rb, Rb1, or Rb2 independently of one another together with the group Rb, Rb1 or Rb2 attached to an adjacent carbon atom may form a five- or six-membered saturated or partially or fully unsaturated ring which, in addition to carbon atoms, may contain 1, 2 or 3 heteroatoms selected from the group consisting of O, N and S;
• X is O, S or N—R3;
• R3 is hydrogen, C1-C6-alkyl, C1-C4-haloalkyl, C2-C6-alkenyl, C3-C6-alkynyl, Z-C3-C10-cycloalkyl, C1-C6-alkoxy-C1-C6-alkyl, C1-C6-cyanoalkyl, Z-phenyl, Z—C(═O)—Ra2 or tri-C1-C4-alkylsilyl;
• Ra2 is C1-C6-alkyl, C1-C4-haloalkyl, Z—C1-C6-alkoxy, Z—C1-C4-haloalkoxy or NRiRii;
• where in the groups RA, R2, R3 and their subsubtituents, the carbon chains and/or the cyclic groups may be partially or fully substituted by groups Ra,
• or a N-oxide or an agriculturally suitable salt thereof;
• with the proviso that R1 is not ORA or OS(O)n—RA when X is O.