1-(Heteroaryl)pyrazol-4-ylacetic acids, processes for their preparation and their use as herbicides and plant growth regulators

A compound of the formula (I) or a salt thereof

• in which
• each of the divalent groups X1, X2, X3 and X4 is a group of the formula CH, N, NH, O or S, with the proviso that the ring attached at the 1-N atom of the pyrazole ring is a heteroaromatic five-membered ring which is unsubstituted or substituted by radicals R6, where in the case of a substitution a hydrogen atom at a group CH or NH is replaced by a radical R6,
• except for optionally substituted five-membered heteroaromatic radicals having two heteroatoms as ring atoms in which one of the heteroatoms in the ring is a nitrogen atom and the other is a sulfur atom and the nitrogen atom in the ring is located in the 1,3-position to the ring carbon atom which is attached at the 1-N atom of the pyrazole radical,
• R1 is hydrogen or a hydrolyzable radical,
• R2 is hydrogen, halogen or (C1-C6)-alkyl which is unsubstituted or substituted by one or more radicals selected from the group consisting of halogen, (C1-C4)-alkoxy, (C1-C4)-alkylthio and (C1-C4)-haloalkoxy,
• R3 is hydrogen, halogen or (C1-C6)-alkyl which is unsubstituted or substituted by one or more radicals selected from the group consisting of halogen, (C1-C4)-alkoxy, (C1-C4)-alkylthio and (C1-C4)-haloalkoxy, or
• R2 and R3 together with the carbon atom to which they are attached are a carbocyclic saturated or partially unsaturated ring having 3 to 6 carbon atoms which is unsubstituted or substituted by one or more radicals selected from the group consisting of halogen and (C1-C4)-alkyl, and
• R4 is hydrogen, halogen, cyano, (C1-C6)-alkyl, (C2-C6)-alkenyl or (C2-C6)-alkynyl,
• where each of the three lastmentioned radicals is unsubstituted or substituted by one or more radicals selected from the group consisting of halogen, cyano, hydroxyl, (C1-C4)-alkoxy, (C1-C4)-haloalkoxy, (C1-C4)-alkoxy-(C1-C4)-alkoxy, (C1-C4)-alkylthio and optionally halogen-, cyano-, (C1-C4)-alkyl- or (C1-C4)-haloalkyl-substituted (C3-C9)-cycloalkyl, or
• is (C3-C9)-cycloalkyl, (C5-C9)-cycloalkenyl or (C5-C9)-cycloalkynyl, where each of the 3 lastmentioned radicals is unsubstituted or substituted by one or more radicals selected from the group consisting of halogen, (C1-C4)-alkyl, (C1-C4)-haloalkyl, (C2-C4)-alkenyl, (C2-C4)-alkynyl, (C1-C4)-alkoxy, (C1-C4)-haloalkoxy and (C1-C4)-alkylthio, or
• is phenyl which is unsubstituted or substituted by one or more radicals selected from the group consisting of halogen, cyano, nitro, carboxyl, (C1-C4)-alkyl, (C1-C4)-haloalkyl, (C2-C4)-alkenyl, (C2-C4)-alkynyl, (C1-C4)-alkoxy, (C1-C4)-haloalkoxy, (C1-C4)-alkoxy-(C1-C4)-alkoxy, (C1-C4)-alkylthio, (C1-C4)-alkanoyl, (C1-C4)-haloalkanoyl, [(C1-C4)-alkoxy]carbonyl and [(C1-C4)-haloalkoxy]carbonyl, or
• is (C1-C6)-alkanoyl which is unsubstituted or substituted by one or more radicals selected from the group consisting of halogen, cyano, (C1-C4)-alkoxy, (C1-C4)-haloalkoxy, (C1-C4)-alkoxy-(C1-C4)-alkoxy, (C1-C4)-alkylthio and optionally halogen-, cyano-, (C1-C4)-alkyl- or (C1-C4)-haloalkyl-substituted (C3-C6)-cycloalkyl, or
• is [(C1-C4)-alkoxy]carbonyl which is unsubstituted or substituted by one or more radicals selected from the group consisting of halogen, cyano, (C1-C4)-alkoxy, (C1-C4)-haloalkoxy, (C1-C4)-alkoxy-(C1-C4)-alkoxy, (C1-C4)-alkylthio and optionally halogen-, cyano-, (C1-C4)-alkyl- or (C1-C4)-haloalkyl-substituted (C3-C6)-cycloalkyl, or
• is [(C3-C9)-cycloalkoxy]carbonyl which is unsubstituted or substituted by one or more radicals selected from the group consisting of halogen, (C1-C4)-alkyl, (C1-C4)-haloalkyl, (C2-C4)-alkenyl, (C2-C4)-alkynyl, (C1-C4)-alkoxy, (C1-C4)-haloalkoxy and (C1-C4)-alkylthio,
• R5 is an aryl radical which is unsubstituted or substituted and, including substituents, has 6 to 30 carbon atoms, or
• is a heteroaromatic radical having 1 to 4 ring heteroatoms selected from the group consisting of N, O and S which is unsubstituted or substituted and, including substituents, has 1 to 30 carbon atoms, and
• (R6)n are n substituents R6, where R6, in the case that n=1, or each of the substituents R6 independently of the others, in the case that n is greater than 1, is a radical halogen, hydroxyl, amino, nitro, carboxyl, cyano, carbamoyl, (C1-C6)-alkyl, (C1-C6)-haloalkyl, (C1-C4)-alkoxy-(C1-C4)-alkyl, (C1-C4)-alkylthio-(C1-C4)-alkyl, mono- or di-[(C1-C4)-alkyl]aminoalkyl, hydroxy-(C1-C4)-alkyl, (C1-C6)-alkyl which is substituted
• by optionally halogen-, cyano-, (C1-C4)-alkyl- or (C1-C4)-haloalkyl-substituted (C3-C6)-cycloalkyl,
• by optionally halogen-, cyano-, (C1-C4)-alkyl-, (C1-C4)-haloalkyl- or (C1-C4)-alkoxy-substituted phenyl or
• by optionally halogen-, cyano-, (C1-C4)-alkyl-, (C1-C4)-haloalkyl- or (C1-C4)-alkoxy-substituted heterocyclyl,
• or (C2-C6)-alkenyl, (C2-C6)-haloalkenyl, (C2-C6)-alkynyl, (C2-C6)-haloalkynyl, (C1-C6)-alkoxy, (C1-C6)-haloalkoxy, (C1-C4)-alkoxy-(C1-C4)-alkoxy, (C1-C6)-alkylthio, (C1-C6)-haloalkylthio, [(C1-C6)-alkoxy]carbonyl, [(C1-C6)-haloalkoxy]carbonyl, (C1-C6)-alkanoyl, (C1-C6)-haloalkanoyl, mono- or di-[(C1-C4)-alkyl]aminocarbonyl, mono- or di-[(C1-C6)-acyl]amino, mono- or di-[(C1-C4)-alkyl]amino, N—[(C1-C6)-acyl]-N—[(C1-C6)-alkyl]amino, (C1-C6)-alkylsulfinyl, (C1-C6)-haloalkylsulfinyl, (C1-C6)-alkylsulfonyl, (C1-C6)-haloalkylsulfonyl, (C3-C9)-cycloalkyl, (C5-C9)-cycloalkenyl,
• where each of the two lastmentioned radicals is unsubstituted or substituted by one or more radicals selected from the group consisting of halogen, (C1-C4)-alkyl and (C1-C4)-haloalkyl,
• or optionally halogen-, cyano-, (C1-C4)-alkyl-, (C1-C4)-haloalkyl- or (C1-C4)-alkoxy-substituted heterocyclyl, and
• n is 0, 1, 2 or 3.