GB2519092A - Herbicidal Compounds - Google Patents

Abstract

A compound of formula (I): wherein R1 is a substituent; R2 is selected from hydrogen and a substituent; R4 is selected from hydrogen, OH and halogen; R5 is selected from hydrogen and halogen, or R4 and R5 form an optionally substituted aryl/heteroaryl ring; Q is a 5- or 6-membered aryl/heteroaryl ring; X is a substituent; G is selected from hydrogen and C(O)R6 where R6 is a substituent; n is 0,1,2,3,4; Preferred compounds include those where R1=R2=Me, Q is substituted thienyl and R4=R5=Cl. Other preferred compounds include those where R1=R2=Me, Q is phenyl and R4 and R5 form a phenyl ring, which together with the pyrrole ring to which both phenyl rings are mutually condensed forms a carbazole ring system. Also, herbicidal compositions comprising such compounds and their use in controlling undesirable plant and in particular the use in controlling weeds, such as broad-leaved dicotyledonous weeds, in crops of useful plants.

Description

Herbicidal Compounds The present invention relates to herbicidal pyridazinone derivatives, in particular pyridazinone derivatives substituted with a bi-cyclic-or tn-cyclic heteroaromatic moiety, as well as processes and intermediates used for the preparation of such derivative. The invention further extends to herbicidal compositions comprising such pyridazinone derivatives as well as to the use of such compounds and compositions in controlling undesirable plant and in particular the use in controlling weeds, such as broad-leaved dicotyledonous weeds, in crops of useful plants.

Herbicidal pyridazinones are known from W020091086041. In addition, herbicidal 5/6 membered heterocyclyl-substituted pyridazinones are known from W02011/045271. Co- pending International Patent Application No. PCT/EP2013/057676 also discloses indolyl-pyridazinone derivatives having herbicidal utility. The present invention is based upon the finding that pyridazinone derivatives substituted with a bi-cyclic-or tn-cyclic heteroaromatic moiety also exhibit excellent herbicidal properties.

Thus, in a first aspect there is provided a compound of formula (I) 4 P

R

N.,,.L.. [X] (I) or a salt or N-oxide thereof, wherein R1 is selected from the group consisting of Cr04 alkyl, 01-02 alkoxy-01-C2 alkyl, C204 alkenyl, 01-04 haloalkyl, 02-C4 haloalkenyl, C2-C4 alkynyl and C2-C4 haloalkynyl; R2 is selected from the group consisting of hydrogen, halogen, cyano, C1-C6alkyl, C1-C6haloalkyl, C1-C5haloalkoxy, C1-C3haloalkoxy-C1- C3alkyl-, C1-C6alkoxy, C1-C3alkoxy-C1-C3alkyl, C1-C3alkoxy-C1-C3alkoxy-C1-C3alkyl-, C3- C6cycloalkyl, C2-C6 alkenyl, C2-C6 haloalkenyl, C2-C6 alkynyl, Ci-C6hydroxyalkyl-, C- C6alkylcarbonyl-, -S(O)O1-C6alkyl. amino, 01-C6alkylamino, 01-C6dialkylamino, -C(Ci-C3alkyl)=N-O-C1-C3alkyl and CrC6 haloalkynyl; R4 is hydrogen, hydroxyl or halogen; R5 is hydrogen or halogen; or, R4 and R5 together with the carbon atoms to which they are joined form a 5-or 6-membered optionally substituted aryl or heteroaryl ring; 0 is a 5-or 6-membered aryl or heteroaryl ring; each X is independently, hydroxyl, halogen, nitro, cyano, amino, 01-06 alkyl, 01-C6haloalkyl, C3-C6cycloalkyl, C1-C6 alkoxy, C1-C6alkoxyl carbonyl or -S(O)C1-C6alkyl, G is hydrogen or -C(O)-R6; R6 is selected from the group consisting of C1-C6alkyl, C1-C5alkenyl, C1-C6alkynyl, 01-C6alkyl-S-, C1-C6alkoxy, -NR'R8 and phenyl optionally substituted by one or more R9; R7 and R8 are independently selected from the group consisting of C1-C6 alkyl, C1-C6 alkoxy-; or P7 and P8 can together form a morpholinyl ring; P9 is selected from the group consisting of halogen, cyano, nitro, Ci-C3alkyl, Ci-C3haloalkyl, Ci-C3alkoxy and C-C3haloalkoxy; n = 0,1,2,3 or 4; and p = 0,1 or 2; provided that when 0 is a 6-membered aromatic ring and P5 is chlorine or bromine, P4 is hydroxyl, fluorine or iodine.

Each alkyl moiety either alone or as part of a larger group (such as alkoxy, alkylthio, alkoxycarbonyl, alkylcarbonyl, alkylaminocarbonyl, or dialkylaminocarbonyl, et al.) may be straight-chained or branched. Typically, the alkyl is, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, or n-hexyl. The alkyl groups are generally Ci-C6alkyl groups (except where already defined more narrowly), but are preferably Ci-C4alkyl or Ci-C3alkyl groups (except where already defined more narrowly), and, more preferably, are C1-C2alkyl groups (such as methyl).

Alkenyl and alkynyl moieties can be in the form of straight or branched chains, and the alkenyl moieties, where appropriate, can be of either the (E)-or (Z)-configuration. The alkenyl or alkynyl are typically 02-C4alkenyl or C2-C4alkynyl, more specifically vinyl, allyl, ethynyl, propargyl or prop-1-ynyl. Alkenyl and alkynyl moieties can contain one or more double and/or triple bonds in any combination; but preferably contain only one double bond (for alkenyl) or only one triple bond (for alkynyl).

Preferably, the term cycloalkyl refers to cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl.

In the context of the present specification the term "aryl" preferably means phenyl. The term "heteroaryl" as used herein means an aromatic ring system containing at least one ring heteroatom and consists of a single ring. Preferably, single rings will contain 1, 2 or 3 ring heteroatoms selected independently from nitrogen, oxygen and sulfur. Typically "heteroaryl" is furyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl, 1,2,5-oxadiazolyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,3,4-thiadiazolyl, 1,2,5-thiadiazolyl, pyridyl, pyrimidinyl, pyridazinyl, pyrazinyl, 1,2,3-triazinyl, 1,2,4-triazinyl, or 1,3,5-triazinyl.

Halogen (or halo) encompasses fluorine, chlorine, bromine or iodine. The same correspondingly applies to halogen in the context of other definitions, such as haloalkyl or halophenyl.

Haloalkyl groups having a chain length of from 1 to 6 carbon atoms are, for example, fluoromethyl, difluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl, trichloromethyl, 2,2,2-trifluoroethyl, 2-fluoroethyl, 2-chloroethyl, pentafluoroethyl, 1,1 -difluoro-2,2,2-trichloroethyl, 2,2,3,3-tetrafluoroethyl and 2,2,2-trichloroethyl, heptafluoro-n-propyl and perfluoro-n-hexyl.

Alkoxy groups preferably have a chain length of from ito 6 carbon atoms. Alkoxy is, for example, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy or tert-butoxy or a pentyloxy or hexyloxy isomer, preferably methoxy and ethoxy. It should also be appreciated that two alkoxy substituents present on the same carbon atom.

Haloalkoxy is, for example, fluoromethoxy, difluoromethoxy, trifluoromethoxy, 2,2,2-trifluoroethoxy, 1,1,2,2-tetrafluoroethoxy, 2-fluoroethoxy, 2-chloroethoxy, 2,2-difluoroethoxy or 2.2.2-trichloroethoxy, preferably difluoromethoxy, 2-chloroethoxy or trifluoromethoxy.

Ci-Cealkyl-S-(alkylthio) is, for example, methylthio, ethylthio, propylthio, isopropylthio, n-butylthio, isobutylthio, sec-butylthio or tert-butylthio, preferably methylthio or ethylthio.

C1-C5alkyl-S(O)-(alkylsulfinyl) is, for example, methylsulfinyl, ethylsulfinyl, propylsulfinyl, isopropylsulfinyl, n-butylsulfinyl, isobutylsulfinyl, sec-butylsulfinyl or tert-butylsulfinyl, preferably methylsulfinyl or ethylsulfinyl.

C1-C6alkyl-S(O)2-(alkylsulfonyl) is, for example, methylsulfonyl, ethylsulfonyl, propylsulfonyl, isopropylsulfonyl, n-butylsulfonyl, isobutylsulfonyl, sec-butylsulfonyl or tert-butylsulfonyl, preferably methylsulfonyl or ethylsulfonyl.

Compounds of Formula (I) may contain asymmetric centres and may be present as a single enantiomer, pairs of enantiomers in any proportion or, where more than one asymmetric centre are present, contain diastereoisomers in all possible ratios. Typically one of the enantiomers has enhanced biological activity compared to the other possibilities.

Similarly, where there are di-substituted alkenes, these may be present in E or Z form or as mixtures of both in any proportion.

Furthermore, compounds of formula (I) may be in equilibrium with alternative tautomeric forms. It should be appreciated that all tautomeric forms (single tautomer or mixtures thereof), racemic mixtures and single isomers are included within the scope of the present invention.

The present invention also includes agronomically acceptable salts that the compounds of formula (I) may form with amines (for example ammonia, dimethylamine and triethylamine), alkali metal and alkaline earth metal bases or quaternary arnmonium bases. Among the alkali metal and alkaline earth metal hydroxides, oxides, alkoxides and hydrogen carbonates and carbonates used as salt formers, emphasis is to be given to the hydroxides, alkoxides, oxides and carbonates of lithium, sodium, potassium, magnesium and calcium, but especially those of sodium, magnesium and calcium. The corresponding trimethylsulfonium salt may also be used.

The compounds of formula (I) according to the invention also include hydrates which may be formed during the salt formation.

Preferred values of R1, R2, R4, R5, R6, R', R8, R°, G, Q, X, n, and p are as set out below, and a compound of formula (I) according to the invention may comprise any combination of said values.

R1 is preferably methyl, ethyl, or n-propyl. In one set of embodiments, R1 is methyl.

In one set of embodiments R2 is selected from the group consisting of hydrogen, halogen, Ci-C6alkyl, Ci-C6haloalkyl, Ci-C6alkoxy, Ci-C3alkoxy-Ci-C3alkyl, C3-C6cycloalkyl, C2-C6alkenyl. 02-C6haloalkenyl, 02-06 alkynyl and C2-C6haloalkynyl. More preferably R2 is selected from the group consisting of hydrogen, methyl, ethyl, cyclopropyl and methoxymethyl.

Most preferably R2 is methyl.

In one set of embodiments it is preferred that F' is hydrogen or halogen, more preferably hydrogen or chlorine.

In one set of embodiments it is preferred that R5 is halogen, more preferably chlorine.

In a further set of embodiments it is preferred that R4 and R5 together with the carbon atoms to which they are joined form a phenyl ring, optionally substituted by 1-3 groups (preferably 1-2 groups) Y, wherein each Y is independently hydroxyl, halogen, nitro, cyano, amino, 01-06 alkyl, C1-O6haloalkyl, C3-O6cycloalkyl, 01-06 alkoxy, 01-C6alkoxyl carbonyl or - S(O)C1-C6alkyl. Preferably each Y is independently hydroxyl, halogen, C1-C3alkyl, C1-C3alkoxy, C1-C3haloalkyl, or C1-C3haloalkoxy, more preferably Y is halogen, most preferably Cl.

In such embodiments, it is preferred that R4 and R5 together with the carbon atoms to which they are joined form an unsubstituted phenyl ring, or a phenyl ring substituted by 1-3 chlorine substituents, more preferably 1 or 2 chlorine substituents.

As stated above, 0 is a 5-or 6-membered aryl or heteroaryl ring, more specifically 0 is a phenyl, thienyl, furyl, pyrrolyl, isoxazolyl, oxazolyl, isothiazolyl, thiazolyl, pyrazolyl, imidazolyl, triazolyl, tetrazolyl, pyridyl, pyrimidinyl, pyrazinyl, triazinyl, pyridazinyl, oxadiazolyl or thiadiazolyl ring. Preferably 0 is a phenyl, thienyl, furyl, thiazolyl, imidazolyl, oxazolyl, pyrazolyl, or triazolyl ring. More preferably 0 is a phenyl or thienyl ring.

In one set of embodiments, 0 is phenyl and R4 and R6 together with the carbon atoms to which they are joined form a phenyl ring. Thus compounds of formula (I) in this set of embodiments have the general formula (I-I) n RLJL)J [X] P2 (I-I) wherein X, n, R1, R2, and G are as defined herein (including any combination of preferred options for said substituents).

Preferably X is hydroxyl, halogen, 01-C5alkyl, C1-C6haloalkyl, C1-C6alkoxy, or C- C6haloalkoxy. More preferably X is halogen, C1-C3alkyl, C1-C3haloalkyl, C1-C3alkoxy, or C1-C3haloalkoxy. More preferably still, X is halogen, Ci-C3alkyl, or Ci-C3haloalkyl. Yet even more preferably X is C1-C3 alkyl, especially methyl, or halogen, especially chlorine.

S Preferably n is an integer or 0, 1, or 2.

As described herein, 0 may be hydrogen or -C(O)-R6, and R6 is selected from the group consisting of Ci-C6alkyl. C2-C6alkenyl. C2-C6alkynyl, C1-C6alkyl-S-. Ci-C6alkoxy. -NR7R8 and phenyl optionally substituted by one or more R9. As defined herein, R7 and R8 are independently selected from the group consisting of C1-C6 alkyl, C1-C6 alkoxy-; or they can together form a morpholinyl ring. Preferably R7 and R8 aie each independently selected from the group consisting of methyl, ethyl, propyl, methoxy, ethoxy and propoxy. P° is selected from the group consisting of halogen, cyano, nitro, C1-C3alkyl, C1-C3haloalkyl, C1-C3alkoxy and Ci-C3haloalkoxy.

Preferably S6 is C1-C4 alkyl, CrC3alkenyl, CrC3alkynyl,-Ci-C3alkoxy, or -NR7R8 wherein R' and 8 together form a morpholinyl ring. More preferably 6 is isopropyl, t-butyl, methyl, ethyl, propargyl or methoxy.

In one set of embodiments 0 is hydrogen or -C(O)-R6' wherein 6 is Ci-C4 alkyl, C2- C3alkenyl, C2-C3alkynyl or -C1-C3alkoxy. In a further set of embodiments 0 is hydrogen or -C(O)-R6' wherein R6 is isopropyl, t-butyl, methyl, ethyl, propargyl or methoxy. However, it is particularly preferred that G is hydrogen.

In one set of embodiments, Q is phenyl and 4 and 5 together with the carbon atoms to which they are joined form a phenyl ring Table 1 below provides 35 specific examples of compounds of formula (I) of the invention.

TABLE I Examples of herbicidal compounds of the present invention.

This table covers 35 compounds of formula (IA), wherein R1 and R2 are each methyl,

A 0 0

RvN.N R2 (IA), which are compounds of formula (I) wherein A is a group of genehc formula [X] (A), and R4, R5, Q, n and X thus have the values given in the table Compound GroupA _________________ 0 n X 1.001 -(CH)4-phenyl 0 -1.002 Cl Cl Cl thienyl 1 CH3 Cl ___

L

1.003 s Cl Cl Cl thienyl 2 CH3, Cl Cl

CI 1.004

H Cl thienyl 1 CH3 J-. 1.005

Cl H thienyl 1 Cl-I3 A-.

1.006 -(CH)4-thienyl 0 - 1.007 -(CH)4-thienyl 2 Cl, Cl ClØ

CL

1.008 ci -(CH)2-(CCI)-(CH)-thienyl 2 Cl, Cl 1.009 H CI fljryl 1 GEl3 1.010 ci Ci Ci firyI I CH3 cI ___ 1.011 Ci Ci ftryI 2 CH3: ci Ci ci 1.012 ci CI Ci thiazolyl I CH3 1.013 H CI thiazolyl 1 CH3 1.014 N Ci Ci CI thiazolyl 1 CH3 1.015 N CI H Ci thiazolyl 1 GEl3 1.016 Ci Ci thienyl I CH3 1.017 H Ci thienyl I CH3

S

1.018 CI CI thienyl 1 CH3 I.' 1.019 I CI CI imidazolyl 2 CH3: N01 CH3 1.020 I H CI imidazolyl 2 CH3. CH3

1.02 1 CI CI oxazolyl 1 CH3 1. 1.022

N01 H CI oxazolyl 1 CH3

L 1.023

CI CI oxazolyl 1 CH3 1.024 0ci H CI oxazolyl I CH3 1.025 CI Kiryl 0 -1.

1.026 ci H CI JryI 0 -is 1.027 CI CI thienyl 0 -ccI _____ 1.

1.028 ci CI CI thienyl I CI

CI

1.029 H CI thienyl 0 -1.

1.030 CI CI pyrazolyl 1 CH3 1.031 H CI pyrazolyl 1 CH3

L

1.032 ci CI CI pyrazolyl 1 CH3 J-.

1.033 ci H CI pyrazolyl 1 Cl-I3

L

1.034 ci CI CI triazolyl 1 CH3 J-.

1.035 H CI triazolyl I CH3

L

The compounds of the present invention may be prepared according to the following schemes, in which the substituents R1, R2, R4, R5, Q, X and n have (unless otherwise stated explicitly) the definitions described hereinbefore.

Compounds of formula (I) of the invention may be prepared from compounds of formula (1) by heating with morpholine as shown below in Reaction scheme 1.

Reaction scheme 1 H 5

END

RJLN.JQ) 0 RJLN..J NLOMe'S)q A N4 (1) Compounds of formula (1) may be prepared by coupling of pyridazinones of formula (2) with iing-fused heterocycles of foimula (3), as shown below in Reaction scheme 2.

Reaction scheme 2 R1)t1OMe + Base N1 SoInt NOMe [ R [) R (2) (3) (1) Compounds of formula (1) may be prepared by reacting pyridazinones (2) with ring-fused building blocks (3), in the presence of a strong base such as sodium hydride or sodium hexamethyldisilazide (NaHMDS). Suitable solvents include tetrahydrofuran (THE) or dimethylformamide (DMF). An example of a compound of formula (3) is 2-methyl-4H-thieno[3,2-b]pyriole, prepaied as described in Inteinational Patent Publication No. WO 2007/126052. A further example of a compound of formula (3) is carbazole, which is readily commercially available.

Examples of compounds of formula (2) include 6-bromo-5-chloro-4-methoxy-2-methyl-pyiidazin-3-one and 5-chloro-4-methoxy-2,6-dimethyl-pyridazin-3-one, both prepaied accoiding to Reaction scheme 3, shown below.

Reaction scheme 3 0 0 HN Br2 HN)CI Mel 0 N01 H20 4CI K2C03 MeCI Br DMF CI Br o 0 NaOMe Me CI Me OMe N i ____________ 1 N 4-D io ne Br Br O Me Pd(dppf)C12.DCM 0 I (cat.) Me OMe Me OMe + ° _______ MeOMe CsF CI Br DME Me

C 70%

A variation used to access certain halogenated derivatives of the present invention is illustrated by Reaction scheme 4. Ceitain compounds of formula (1), an example being (ic), are viable substrates for an additional electrophilic halogenation step. Halogenation, more specifically chlorination, of (ic) constitutes a preparation of intermediates (la) and (ib) as shown in Reaction scheme 4.

Reaction scheme 4 CI ci + s020l2 0 rK o -

-I

OMe CH2CI2 NyTh. OM" Ni ci (ic) (la) (Ib) Compounds of foimula (la) and (ib) may be piepaied by leacting (ic) with sulfuryl chloride in dichloromethane.

A further variation used to access certain compounds of the present invention is illustrated by Reaction scheme 5. Certain compounds of formula (1) wherein P2 is bromine, may be converted to derivatives bearing methyl as R2, as shown for the methylation of (id) S below, which is carried out by heating with trimethylboroxine and aqueous base in the presence of a suitable solvent and suitable catalyst. Suitable solvents include 1,4-dioxane, and suitable catalysts are palladium based! e.g. 1,1'-Bis(diphenylphosphino)ferrocene-palladium(ll)di-chloride.

Reaction scheme 5 CS2CO3 OMe Pd(dppf)C12.CH2CI2 OMe Br 1,4-dioxane H20 (Id) (le) Certain intermediate compounds used in the production of compounds of formula (I) are also novel, and as such form a further aspect of the invention. Thus the invention also provides a compound of formula (1) R4 5 OMe 2 pqn R (1), wherein R1, R2, R4, R5, 0, X, and n are as defined herein.

The compounds of Formula (I) according to the invention can be used as herbicides by themselves, but they are generally formulated into herbicidal compositions using formulation adjuvants, such as carriers, solvents and surface-active agents (SFAs). Thus, the present invention further provides a herbicidal composition comprising a herbicidal compound according to any one of the previous claims and an agriculturally acceptable formulation adjuvant. The composition can be in the form of concentrates which are diluted prior to use, although ready-to-use compositions can also be made. The final dilution is usually made with water, but can be made instead of, or in addition to, water, with, for example, liquid fertilisers, micronutrients, biological organisms, oil or solvents.

The herbicidal compositions generally comprise from 0.1 to 99 % by weight, especially from 0.1 to 95 % by weight, compounds of Formula I and from 1 to 99.9 % by weight of a formulation adjuvant which preferably includes from 0 to 25 % by weight of a surface-active substance.

The compositions can be chosen from a number of formulation types, many of which are known from the Manual on Development and Use of FAO Specifications for Plant Protection Products, 5th Edition! 1999. These include dustable powders (DP), soluble powders (SP), water soluble granules (SG), water dispersible granules (WG), wettable powders (WP), granules (OR) (slow or fast release), soluble concentrates (SL), oil miscible liquids (OL), ultra low volume liquids (UL), emulsifiable concentrates (EC), dispersible concentrates (DC), emulsions (both oil in water (EW) and water in oil (EO)), micro-emulsions (ME), suspension concentrates (SC), aerosols, capsule suspensions (CS) and seed treatment formulations. The formulation type chosen in any instance will depend upon the particular purpose envisaged and the physical, chemical and biological properties of the compound of Formula (I).

Dustable powders (DP) may be prepared by mixing a compound of Formula (I) with one or more solid diluents (for example natural clays, kaolin, pyrophyllite, bentonite, alumina, montmorillonite, kieselguhr, chalk, diatomaceous earths, calcium phosphates, calcium and magnesium carbonates, sulphur, lime, flours, talc and other organic and inorganic solid carriers) and mechanically grinding the mixture to a tine powder.

Soluble powders (SP) may be prepared by mixing a compound of Formula (I) with one or more water-soluble inorganic salts (such as sodium bicarbonate, sodium carbonate or magnesium sulphate) or one or more water-soluble organic solids (such as a polysaccharide) and, optionally, one or more wetting agents, one or more dispersing agents or a mixture of said agents to improve water dispersibility/solubility. The mixture is then ground to a fine powder.

Similar compositions may also be granulated to form water soluble granules (SG).

Wettable powders (WP) may be prepared by mixing a compound of Formula (I) with one or more solid diluents or carriers, one or more wetting agents and, preferably, one or more dispersing agents and, optionally, one or more suspending agents to facilitate the dispersion in liquids. The mixture is then ground to a fine powder. Similar compositions may also be granulated to form water dispersible granules (WG).

Granules (GR) may be formed either by granulating a mixture of a compound of Formula (I) and one or more powdered solid diluents or carriers, or from pre-formed blank granules by absorbing a compound of Formula (I) (or a solution thereof, in a suitable agent) in a porous granular material (such as pumice, attapulgite clays, fuller's earth, kieselguhr, diatomaceous earths or ground corn cobs) or by adsorbing a compound of Formula (I) (or a solution thereof, in a suitable agent) on to a hard core material (such as sands, silicates, mineral carbonates, suiphates or phosphates) and drying if necessary. Agents which are commonly used to aid absorption or adsorption include solvents (such as aliphatic and aromatic petroleum solvents, alcohols, ethers, ketones and esters) and sticking agents (such as polyvinyl acetates, polyvinyl alcohols, dextrins, sugars and vegetable oils). One or more other additives may also be included in granules (for example an emulsifying agent, wetting agent or dispersing agent).

Dispersible Concentrates (DC) may be prepared by dissolving a compound of Formula (I) in water or an organic solvent, such as a ketone, alcohol or glycol ether. These solutions may contain a surface active agent (for example to improve water dilution or prevent crystallisation in a spray tank).

Emulsifiable concentrates (EC) or oil-in-water emulsions (EW) may be prepared by dissolving a compound of Formula (I) in an organic solvent (optionally containing one or more wetting agents, one or more emulsifying agents or a mixture of said agents). Suitable organic solvents for use in ECs include aromatic hydrocarbons (such as alkylbenzenes or alkylnaphthalenes, exemplified by SOLVESSO 100, SOLVESSO 150 and SOLVESSO 200; SOLVESSO is a Registered Trade Mark), ketones (such as cyclohexanone or methylcyclohexanone) and alcohols (such as benzyl alcohol, furfuryl alcohol or butanol), N-alkylpyrrolidones (such as N-methylpyrrolidone or N-octylpyrrolidone), dimethyl amides of fatty acids (such as C8-C10 fatty acid dimethylamide) and chlorinated hydrocarbons. An EC product may spontaneously emulsify on addition to water, to produce an emulsion with sufficient stability to allow spray application through appropriate equipment.

Preparation of an EW involves obtaining a compound of Formula (I) either as a liquid (if it is not a liquid at room temperature, it may be melted at a reasonable temperature, typically below 70°C) or in solution (by dissolving it in an appropriate solvent) and then emulsifying the resultant liquid or solution into water containing one or more SFAs, under high shear, to produce an emulsion. Suitable solvents for use in EWs include vegetable oils, chlorinated hydrocarbons (such as chlorobenzenes), aromatic solvents (such as alkylbenzenes or alkylnaphthalenes) and other appropriate organic solvents which have a low solubility in water.

Microemulsions (ME) may be prepared by mixing water with a blend of one or more solvents with one or more SFAs, to produce spontaneously a thermodynamically stable isotropic liquid formulation. A compound of Formula (I) is present initially in either the water or the solventtSFA blend. Suitable solvents for use in MEs include those hereinbefore described for use in in ECs or in EWs. An ME may be either an oil-in-water or a water-in-oil system (which system is present may be determined by conductivity measurements) and may be suitable for mixing water-soluble and oil-soluble pesticides in the same formulation. An ME is suitable for dilution into water, either remaining as a microemulsion or forming a conventional oil-in-water emulsion.

Suspension concentrates (SC) may comprise aqueous or non-aqueous suspensions of finely divided insoluble solid particles of a compound of Formula (I). SCs may be prepared by ball or bead milling the solid compound of Formula (I) in a suitable medium, optionally with one or more dispersing agents, to produce a fine particle suspension of the compound. One or more wetting agents may be included in the composition and a suspending agent may be included to reduce the rate at which the particles settle. Alternatively, a compound of Formula (I) may be dry milled and added to water, containing agents hereinbefore described, to produce the desired end product.

Aerosol formulations comprise a compound of Formula (I) and a suitable propellant (for example n-butane). A compound of Formula (I) may also be dissolved or dispersed in a suitable medium (for example water or a water miscible liquid, such as n-propanol) to provide compositions for use in non-pressurised, hand-actuated spray pumps.

Capsule suspensions (CS) may be prepared in a manner similar to the preparation of EW formulations but with an additional polymerisation stage such that an aqueous dispersion of oil droplets is obtained, in which each oil droplet is encapsulated by a polymeric shell and contains a compound of Formula (I) and, optionally, a carrier or diluent therefor. The polymeric shell may be produced by either an interfacial polycondensation reaction or by a coacervation procedure. The compositions may provide for controlled release of the compound of Formula (I) and they may be used for seed treatment. A compound of Formula (I) may also be formulated in a biodegradable polymeric matrix to provide a slow, controlled release of the compound.

The composition may include one or more additives to improve the biological performance of the composition, tor example by improving wetting, retention or distribution on surfaces; resistance to rain on treated surfaces; or uptake or mobility of a compound of Formula (I). Such additives include surface active agents (SFAs), spray additives based on oils, for example certain mineral oils or natural plant oils (such as soy bean and rape seed oil), and blends of these with other bio-enhancing adjuvants (ingredients which may aid or modify the action of a compound of Formula (I)).

Wetting agents, dispersing agents and emulsifying agents may be SFAs of the cationic, anionic, amphoteric or non-ionic type.

Suitable SFAs of the cationic type include quaternary ammonium compounds (for example cetyltrimethyl ammonium bromide), imidazolines and amine salts.

Suitable anionic SEAs include alkali metals salts of fatty acids, salts of aliphatic monoesters of sulphuric acid (for example sodium lauryl sulphate), salts of sulphonated aromatic compounds (for example sodium dodecylbenzenesulphonate, calcium dodecylbenzenesulphonate, butylnaphthalene suiphonate and mixtures of sodium di- /sopropyl-and tri-/sopropyl-naphthalene suiphonates), ether suiphates, alcohol ether suiphates (for example sodium laureth-3-sulphate), ether carboxylates (for example sodium laureth-3-carboxylate), phosphate esters (products from the reaction between one or more fatty alcohols and phosphoric acid (predominately mono-esters) or phosphorus pentoxide (predominately di-esters), for example the reaction between lauryl alcohol and tetraphosphoric acid; additionally these products may be ethoxylated), sulphosuccinamates, paraffin or olefine sulphonates, taurates and lignosulphonates.

Suitable SFAs of the amphoteric type include betaines, propionates and glycinates.

Suitable SFAs of the non-ionic type include condensation products of alkylene oxides, such as ethylene oxide, propylene oxide, butylene oxide or mixtures thereof, with fatty alcohols (such as oleyl alcohol or cetyl alcohol) or with alkylphenols (such as octylphenol, nonylphenol or octylcresol); partial esters derived from long chain fatty acids or hexitol anhydrides; condensation products of said partial esters with ethylene oxide; block polymers (comprising ethylene oxide and propylene oxide); alkanolamides; simple esters (for example fatty acid polyethylene glycol esters); amine oxides (for example lauryl dimethyl amine oxide); and lecithins.

Suitable suspending agents include hydrophilic colloids (such as polysaccharides, polyvinylpyrrolidone or sodium carboxymethylcellulose) and swelling clays (such as bentonite or attapulgite).

The composition of the present may further comprise at least one additional pesticide.

For example, the compounds according to the invention can also be used in combination with other herbicides or plant growth regulators.

In a preferred embodiment the additional pesticide is a herbicide and/or herbicide safener. Examples of such mixtures are (in which I' represents a compound of Formula (I)). I + acetochlor, I + acifluorfen, I + acifluorfen-sodium, I + aclonifen, I + acrolein, I + alachlor, I + alloxydim, I + ametryn, I + amicarbazone, I + amidosulfuron, I + aminopyralid, I + amitrole, I + anilofos, I + asulam, I + atrazine, I + azafenidin, I + azimsulfuron, I + BCPC, I + beflubutamid, I + benazolin, I + bencarbazone, I + benfluralin, I + benfuresate, I + bensulfuron, I + bensulfuron-methyl! I -I-bensulide, I + bentazone, I + benzfendizone, I + benzobicyclon, I + benzofenap, I + bicyclopyrone, I ÷ bifenox, I ÷ bilanafos, I ÷ bispyribac, I ÷ bispyribac-sodium, I ÷ borax, I ÷ bromacil, I + bromobutide, I + bromoxynil, I + butachlor, I + butamifos, I + butralin, I + butroxydim, I + butylate, I + cacodylic acid, I + calcium chlorate, I + cafenstrole, I + carbetamide, I + carfentrazone, I + carfentrazone-ethyl, I + chlorflurenol, I + chlorflurenol-methyl, I + chloridazon, I + chlorimuron, I + chlorimuron-ethyl, I + chloroacetic acid, I + chlorotoluron, I + chlorpropham, I + chlorsulfuron, I + chlorthal, I + chlorthal-dimethyl. I + cinidon-ethyl, I + cinmethylin, I + cinosulfuron, I + cisanilide, I + clethodim, I + clodinafop, I + clodinafop-piopargyl, I + clomazone, I + clomeprop, I + clopyralid, I + cloransulam, I + cloransulam-methyl, I + cyanazine, I + cycloate, I + cyclosulfamuron, I + cycloxydim, I + cyhalofop, I --cyhalofop-butyl,, I + 2,4-0, I + daimuron, I + dalapon, I + dazomet, I + 2,4-DB, I + I + desmedipham, I + dicamba, I + dichiobenil, I + dichiorprop, I + dichlorprop-P, I + diclofop, I + diclofop-methyl, I + diclosulam, I + difenzoquat, I + difenzoquat metilsulfate, I + diflufenican, I + diflufenzopyr, I + dimefuron, I + dimepiperate, I + dimethachior, I + dimethametryn, I + dimethenamid, I + dimethenamid-P, I ÷ dimethipin, I ÷ dimethylarsinic acid, I ÷ dinitramine, I + dinoterb, I ÷ diphenamid, I + dipropetryn, I + diquat, I + diquat dibromide, I + dithiopyr, I + diuron, I + endothal, I + EPTC, I + esprocaib, I + ethalfiuralin, I + ethametsulfuron, I + ethametsulfuron-methyl, I -i-ethephon, I + ethofumesate, I + ethoxyfen, I + ethoxysulfuron, I + etobenzanid, I + fenoxaprop-P, I ÷ fenoxaprop-P-ethyl, I ÷ fentrazamide, I ÷ ferrous sulfate, I + flamprop-M, I ÷ flazasulfuron, I + florasulam, I + fluazifop, I + fluazifop-butyl, I + fluazifop-P, I + fluazifop-P-butyl, I + fluazolate, I + flucarbazone, I + flucarbazone-sodium, I + flucetosulfuron, I + fluchloralin, I + flufenacet, I + flufenpyr, I + flufenpyr-ethyl, I + flumetralin, I + flumetsulam, I + flumiclorac, I + flumiclorac-pentyl, I + flumioxazin, I + flumipropin, I + fluometuron, I + fluoroglycofen, I + fluoroglycofen-ethyl, I + fluoxaprop, I + flupoxam, I + flupropacil, I + flupropanate, I + flupyrsulfuron, I + flupyrsulfuron-methyl-sodium, I + flurenol, I + fluridone, I + flurochloridone, I + fluroxypyr, I + flurtamone, I + fluthiacet, I + fluthiacet-methyl, I + fomesafen, I + foramsulfuron, I + fosamine, I + glufosinate, I + glufosinate-ammonium, I + glyphosate, I + halauxifen, I + halosulfuron, I + halosulfuron-methyl, I + haloxyfop, I + haloxyfop-P, I + hexazinone, I + imazamethabenz, I + imazamethabenz-methyl, I + imazamox, I + imazapic, I + imazapyr, I + imazaquin, I + imazethapyr, I + imazosulfuron, I + indanofan, I + indaziflam, I + iodomethane, I + iodosulfuron, I + iodosulfuron-methyl-sodium, I + ioxynil, I + isoproturon, I + isouron, I + isoxaben, I + isoxachlortole, I + isoxaflutole, I + isoxapyrifop, I + karbutilate, I + lactofen, I + lenacil, I + linuron, I + mecoprop, I + mecoprop-P, I + mefenacet, I + mefluidide, I + mesosulfuron, I + mesosulfuron-methyl, I + mesotrione, I + metam, I + metamifop, I + metamitron, I + metazachlor, I + methabenzthiazuron, I + methazole, I + methylarsonic acid, I + methyldymron, I + methyl isothiocyanate, I + metolachior, I + S-metolachlor, I + metosulam, I + metoxuron, I + metribuzin, I + metsulfuron, I + metsulfuron-methyl, I + molinate, I + monolinuron, I ÷ naproanilide, I ÷ napropamide, I + naptalam, I ÷ neburon, I + nicosulfuron, I + n-methyl glyphosate, I + nonanoic acid, I + norflurazon, I + oleic acid (fatty acids), I + orbencarb, I + orthosulfamuron, I + oryzalin, I + oxadiargyl, I + oxadiazon, I + oxasulfuron, I + oxaziclomefone, I + oxyfluorfen, I + paraquat, I + paraquat dichloride, I + pebulate, I + pendimethalin, I + penoxsulam, I + pentachlorophenol, I + pentanochlor, I 1-pentoxazone, I + pethoxamid, I + phenmedipham, I + picloram, I + picolinafen, I + pinoxaden, I + piperophos, I + pretilachlor, I + piimisulfuron, I + primisulfuron-methyl, I + prodiamine, I + profoxydim, I + prohexadione-calcium, I + prometon, I + prometryn, I + propachior, I + propanil, I + propaquizafop, I + propazine, I + propham, I + propisochior, I + propoxycarbazone, I + propoxycarbazone-sodium, I + propyzamide, I + prosulfocarb, I + prosulfuron, I + pyraclonil, I + pyraflufen, I + pyraflufen-ethyl, I + pyrasulfotole, I + pyrazolynate, I + pyrazosulfuron, I + pyrazosulfuron-ethyl, I + pyrazoxyfen, I + pyribenzoxim, I + pyributicarb, I + pyridafol, I + pyridate, I + pyriftalid, I + pyriminobac, I + pyriminobac-methyl, I + pyrimisulfan, I + pyrithiobac, I + pyrithiobac-sodium, I + pyroxasulfone, I + pyroxsulam, I ÷ quinclorac, I ÷ quinmerac, I ÷ quinoclamine, I ÷ quizalofop, I + quizalofop-P, I + rimsulfuron, I + saflufenacil, I + sethoxydim, I + siduron, I + simazine, I + simetryn, I + sodium chlorate, I + sulcotrione, I + sulfentrazone, I + sulfometuron, I + sulfometuron-methyl, I + sulfosate, I + sulfosulfuron, I + sulfuric acid, I + tebuthiuron, I + tefuryltrione, I + tembotrione, I + tepraloxydim, I + terbacil, I ÷ terbumeton, I + terbuthylazine, I ÷ terbutryn, I + thenylchior, I ÷ thiazopyr, I + thifensulfuron, I + thiencarbazone, I + thifensulfuron-methyl, I + thiobencarb, I + topramezone, I + tralkoxydim, I + tri-allate, I + triasulfuron, I + triaziflam, I + tribenuron, I + tribenuron-methyl, I + triclopyr, I + trietazine, I + trifloxysulfuron, I + trifloxysulfuron-sodium, I + trifluralin, I + triflusulfuron, I + triflusulfuron-methyl, I + trihydroxytriazine, I + trinexapac-ethyl, I + tritosulfuron, I + [3-[2-chloro-4-fluoro-5-(1 -methyl-6-trifluoromethyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-3-yl) phenoxy]-2-pyridyloxy]acetic acid ethyl ester (GAS RN 353292-31-6).

The compounds of the present invention may also be combined with herbicidal compounds disclosed in W006/024820 and/or W007/096576.

The mixing partners of the compound of Formula (I) may also be in the form of esters or salts, as mentioned e.g. in The Pesticide Manual, Fourteenth Edition, British Crop Protection Council, 2006.

The compound of Formula (I) can also be used in mixtures with other agrochemicals such as fungicides, nematicides or insecticides, examples of which are given in The Pesticide Manual.

The mixing ratio of the compound of Formula (I) to the mixing partner is preferably from 1:100 to 1000:1.

The mixtures can advantageously be used in the above-mentioned formulations (in which case "active ingredient" relates to the respective mixture of compound of Formula I with the mixing partner).

The compounds of Formula (I) according to the invention can also be used in combination with one or more safeners. Likewise, mixtures of a compound of Formula I according to the invention with one or more further herbicides can also be used in combination with one or more safeners. The safeners can be AD 67 (MON 4660), benoxacor, cloquintocet-mexyl, cyprosulfamide (GAS RN 221667-31-8). dichlormid, fenchlorazole-ethyl. fenclorim, fluxofenim, furilazole and the corresponding R isomer, isoxadifen-ethyl, mefenpyr-diethyl, oxabetrinil, N-isopropyl-4-(2-methoxy-benzoylsulfamoy-benzamide (CAS RN 221668-34-4).

Other possibilities include safener compounds disclosed in, for example, EP0365484 e.g N-(2-methoxybenzoyl)-4-[(methylaminocarbonyamino]benzenesulfonamide. Particularly preferred are mixtures of a compound of Formula I with cyprosulfamide, isoxadifen-ethyl, cloquintocet-mexyl and/or N-(2-methoxybenzoyl)-4-[(methyl-aminocarbonyl)amino]benzenesulfonamide.

The safeners of the compound of Formula I may also be in the form of esters or salts, as mentioned e.g. in The Pesticide Manual, 141h Edition (BCPC), 2006. The reference to cloquintocet-mexyl also applies to a lithium, sodium, potassium, calcium, magnesium, aluminium, iron, ammonium, quaternary ammonium, sulfonium or phosphonium salt thereof as disclosed in WO 02/34048, and the reference to fenchlorazole-ethyl also applies to fenchlorazole, etc. Preferably the mixing ratio of compound of Formula (I) to safener is from 100:1 to 1:10, especially from 20:1 to 1:1.

The mixtures can advantageously be used in the above-mentioned formulations (in which case "active ingredient" relates to the respective mixture of compound of Formula I with the safener).

The present invention still further provides a method of selectively controlling weeds at a locus comprising crop plants and weeds, wherein the method comprises application to the locus of a weed controlling amount of a composition according to the present invention. Controlling' means killing, reducing or retarding growth or preventing or reducing germination. Generally the plants to be controlled are unwanted plants (weeds). Locus' means the area in which the plants are growing or will grow.

The rates of application of compounds of Formula (I) may vary within wide limits and depend on the nature of the soil, the method of application (pre-or post-emergence; seed dressing; application to the seed furrow; no tillage application etc.), the crop plant, the weed(s) to be controlled, the prevailing climatic conditions, and other factors governed by the method of application, the time of application and the target crop. The compounds of Formula I according to the invention are generally applied at a rate of from 10 to 2000 g/ha, especially from 50 to 1000 g/ha.

The application is generally made by spraying the composition, typically by tractor mounted sprayer for large areas, but other methods such as dusting (for powders), drip or drench can also be used.

Useful plants in which the composition according to the invention can be used include crops such as cereals, for example barley and wheat, cotton, oilseed rape, sunflower, maize, rice, soybeans, sugar beet, sugar cane and turf.

Crop plants can also include trees, such as fruit trees, palm trees, coconut trees or other nuts. Also included are vines such as grapes, fruit bushes, fruit plants and vegetables.

Crops are to be understood as also including those crops which have been rendered tolerant to herbicides or classes of herbicides (e.g. ALS-, GS-, EPSPS-, PPO-, ACCase-and HPPD-inhibitors) by conventional methods of breeding or by genetic engineering. An example of a crop that has been rendered tolerant to imidazolinones, e.g. imazamox, by conventional methods of breeding is Clearfield® summer rape (canola). Examples of crops that have been rendered tolerant to herbicides by genetic engineering methods include e.g. glyphosate-and glufosinate-resistant maize varieties commercially available under the trade names RoundupReady® and LibertyLink®. In a particularly prefeired aspect, the crop plant has been engineered to over-express homogentisate solanesyltransferase as taught in, for example, Crops are also to be understood as being those which have been rendered resistant to harmful insects by genetic engineering methods, for example Bt maize (resistant to European corn borer), Bt cotton (resistant to cotton boll weevil) and also Bt potatoes (resistant to Colorado beetle). Examples of Bt maize are the Bt 176 maize hybrids of NK® (Syngenta Seeds). The Bt toxin is a protein that is formed naturally by Bacillus thur/n glens/s soil bacteria.

Examples of toxins, or transgenic plants able to synthesise such toxins, are described in ER-A- 451 878, EP-A-374 753, WO 93/07278, WO 95/34656, WO 03/052073 and EP-A-427 529.

Examples of transgenic plants comprising one or more genes that code for an insecticidal resistance and express one or more toxins are KnockOut® (maize), Yield Gard® (maize), NuCOTIN33B® (cotton), Bollgard® (cotton), NewLeaf® (potatoes), NatureGard® and Protexcta®. Plant crops or seed material thereof can be both resistant to herbicides and, at the same time, resistant to insect feeding ("stacked" transgenic events). For example, seed can have the ability to express an insecticidal Cry3 protein while at the same time being tolerant to glyphosate.

Crops are also to be understood to include those which are obtained by conventional methods of breeding or genetic engineering and contain so-called output traits (e.g. improved storage stability, higher nutritional value and improved flavour).

Other useful plants include turf grass for example in golf-courses, lawns, parks and roadsides, or grown commercially for sod, and ornamental plants such as flowers or bushes.

The compositions can be used to control unwanted plants (collectively, weeds). The weeds to be controlled inlcude both monocotyledonous species! for example Agrostis, Alopecurus, Avena, Brachiaria, Bromus, Cenchrus, Cyperus, Digitaria, Echinochloa, Eleusine, LoJium, Monochoria, Rottboellia, Sagittaria, Scirpus, Setaria and Sorghum, and dicotyledonous species, for example Abut/Ion, Amaranthus, Ambrosia, Chenopodium, Chrysanthemum, Conyza, Ga/ium, !pomoea, Nasturtium, Sida, Sinapis, So/an urn, Ste//aria, Veronica, Viola and Xanthium. Weeds can also include plants which may be considered crop plants but which are growing outside a crop area (escapes'), or which grow from seed left over from a previous planting of a different crop (volunteers'). Such volunteers or escapes may be tolerant to certain other herbicides.

Various aspects and embodiments of the present invention will now be illustrated in more detail by way of example. It will be appreciated that modification of detail may be made without departing from the scope of the invention.

PREPARATION EXAMPLES

EXAMPLE I Preparation of 4-carbazol-9-yl-2,6-dimethyl-pyridazine-3,5-dione 1.1 Preparation of 3-bromo-4,5-dichloro-1 H-pyridazin-6-one 4,5-dichloro-1 H-pyridazin-6-one (1.95 g, 11.8 mmol, readily commercially available) and bromine (0.73 ml, 14.2 mmol) are suspended in water (10 ml) and the mixture heated under microwave irradiation to 180 °C for 30 mm. The resulting reaction mixture is filtered and the crude solid obtained is washed thoroughly with water, then dichloromethane, to yield 3-bromo- 4,5-dichloro-1 H-pyridazin-6-one, (2.06 g, 72 %) as a white solid. Aol HNy

N..k01 Br 1H NMR (DMSO-d6) 6H 13.88 (1H, br. s).

1.2 Preparation of 6-bromo-4,5-dichloro-2-methyl-pyridazin-3-one To a stirred solution of 3-bromo-4,5-dichloro-1 H-pyridazin-6-one (12.5 g, 51.3 mmol) in DMF (75.0 ml) is added K2C03 (10.7g. 76.9 mmol) and iodomethane (10.9 g, 76.9 mmol, 4.79 ml). The resulting mixture is stirred at ambient temperature for 18 h. The reaction mixture is then poured onto ice-water (300 ml) and the mixture stirred for 2 h. The resulting precipitate is collected by filtration then dried to give 6-bromo-4,5-dichloro-2-methyl-pyridazin-3-one (10.7g.

77 %) as a beige solid. Me ycI Br

1H NMR (CDCI3) 6: 3.83 (3H, s).

1.3 Preparation of 6-bromo-5-chloro-4-methoxy-2-methyl-pyridazin-3-one 6-Bromo-4,5-dichloro-2-methyl-pyridazin-3-one (1.5 g, 5.8 mmol) is dissolved in 1,4-dioxane (150 ml). Sodium methoxide (1.5 ml, 25 mass% methanolic solution, 6.4 mmol) is added dropwise and the reaction stirred for 2 h. The mixture is concentrated to a volume of 50 S ml then diluted with 50 ml EtCAc. It is washed with aqueous saturated brine (2 x 35 ml). The organic layer is dried thoroughly over sodium sulfate, filtered and concentrated in vacuo. The crude residue was purified by flash chromatography (silica gel. 0-10 % EtOAc in isohexane gradient) to afford 6-bromo-5-chloro-4-methoxy-2-methyl-pyridazin-3-one (960 mg, 65%) as a white solid.

Me OMe

N

1H NMR (CDCI3) oH: 3.75 (3 H, s) 4.32 (3 H, s).

1.4 Preparation of 6-bromo-4-carbazol-9-yl-5-methoxy-2-methyl-pyridazin-3-one A solution of carbazole (277 mg, 1.66 mmol, 1.05 Eq.) and 6-bromo-5-chloro-4-methoxy-2-methyl-pyridazin-3-one (400 mg, 1.58 mmol, 1.00 Eq.) in tetrahydrofuran (20 mL) was cooled toO °C. NaHMDS (1 M in tetrahydrofuran) (1.70 mL, 1.70 mmol, 1.10 Eq.) was then added dropwise over 5 mm. After stirring at 0 00 for 20 mm, the reaction mixture was allowed to warm to room temperature and stirred for a further 30 mm. The reaction was quenched at room temperature by the addition of saturated aqueous ammonium chloride solution (25 mL). The mixture was then diluted with ethyl acetate (100 mL) and partitioned with brine (15 mL). The organics were separated, and concentrated under reduced pressure to provide the crude product.

Purification by flash column chromatography provided 6-bromo-4-carbazol-9-yl-5-methoxy-2-methyl-pyridazin-3-one (390 mg, 1.02 mmol, 64%) as a yellow solid. 8Th Nk Br

NMR (400 MHz, CDCI3) OH: 3.27 (3H, s), 3.82 (3H, s), 7.12 (2H, d), 7.31 (2H, t), 7.45 (2H, t), 8.10 (2H, d).

1.5 Preparation of 4-carbazol-9-yl-5-methoxy-2,6-dimethyl-pyridazin-3-one 6-Bromo-4-carbazol-9-yl-5-methoxy-2-methyl-pyridazin-3-one (375 mg, 0.98 mmol), trimethylboroxine (86 mg, 0.68 mmol, 0.7 Eq.), caesium carbonate (395 mg 2.05 mmol, 2.10 Eq.) and 1,1 -Bis(diphenylphosphino)ferrocene-palladium(ll)dichloride dichioromethane S complex (36 mg, 0.05 mmol, 0.05 Eq.) were dissolved in 1,4-dioxane (12 mL) and water (1 mL).

The mixture was heated at reflux for 4 hours. After cooling, the reaction was diluted with ethyl acetate (100 mL) and washed with brine (4 x 20 mL). The organics were passed through a phase separator cartridge and concentrated in vacua. The crude product was purified by flash column chromatography to provide 4-carbazol-9-yl-5-methoxy-2,6-dimethyl-pyridazin-3-one (280 mg, 0.88 mmol, 90%) as a white solid. 8Th

NMR (400 MHz, CDCI3) OH: 2.39 (3H, s), 3.23 (3H, s), 3.77 (3H, s), 7.13 (2H, d), 7.30 (1H, t), 7.44 (2H, t), 8.09 (2H, d).

1.6 Production of 4-carbazol-9-yl-2,6-dimethyl-pyridazine-3,5-dione A solution of 4-carbazol-9-yl-5-methoxy-2,6-dimethyl-pyridazin-3-one (270 mg, 0.85 mmol) in morpholine (7.0 mL) was heated by microwave irradiation to 150 °C for 15 mm. The mixture was allowed to cool then evaporated under reduced pressure to remove most of the morpholine. The crude material was taken up in dichloromethane (30 mL), washed with 2M aq.

hydrochloric solution (5 x 15 mL) and passed through a phase separator cartridge.

Concentration in vacua afforded 4-carbazol-9-yl-2,6-dimethyl-pyridazine-3,5-dione (242 mg, 0.79 mmol, 94%) as a pale yellow solid. 8Th

NMR (400 MHz, MeOH-d4) OH: 2.44 (3H, s), 3.76 (3H, s), 7.10 (2H, d), 7.27 (2H, t), 7.41 (2H, t), 8.14 (2H, d).

EXAMPLE 2. Preparation of 2,6-Dimethyl-4-(3,5,64richloro-2-methyl-thieno[3,2-b]pyrrol- 4-yl)pyridazine-3,5-dione 2.1 Preparation of 5-chloro-4-methoxy-2,6-dimethyl-pyridazin-3-one 6-bromo-5-chloro-4-methoxy-2-methyl-pyridazin-3-one (500 mg, 1.68 mmol, 85 mass% purity, prepared as described above in Example 1 -see steps 1.1, 1.2 and 1.3), CsF (509 mg, 3.353 mmol), trimethylboroxine (242 mg, 1.93 mmol) and [1,1'-Bis(diphenylphosphino)ferrocene]palladium(ll) dichloride dichloromethane adduct (140 mg, 0.168 mmol) are dissolved in 1,2-Dimethoxyethane (5 ml) under N2. The mixture is heated to 145 °C under microwave irradiation for 30 mm. The resulting mixture is filtered through celite, washing with EtOAc. The solution is washed with aqueous saturated brine (2 x 25 mL). The organic layer is separated, dried over Na2SO4, filtered and concentrated in vacuo. The crude residue is purified by flash chromatography (silica gel, eluant a 0-20 % EtOAc in Isohexane gradient). The title compound 5-chloro-4-methoxy-2,6-dimethyl-pyridazin-3-one was obtained as a pale yellow solid (212 mg, 67%).

Me OMe cI Me 1H NMR (CDCI3) SH: 2.37 (3 H, s) 3.72 (3 H, s) 4.26 (3 H, s).

2.2 Preparation of 5-methoxy-2,6-dimethyl-4-(2-methylthieno[3,2-blpyrrol-4-yl) pyridazin-3-one To a stirred solution of 5-chloro-4-methoxy-2,6-dimethyl-pyridazin-3-one (200 mg, 1.06 mmol) and 2-methyl-4H-thieno[3,2-b]pyrrole (145 mg, 1.06 mmol) in THE (5 mL) at 0 °C was added dropwise NaHMDS (1M in THF) (1.10 mL, 1.10 mrnol) over 5 mm. After stirring for 10 mm, the reaction mixture was quenched at 0 °C with saturated ammonium chloride solution (10 mL), then extracted with EtOAc (20 mL x 2). The combined organic layers were dried (MgSO4) and concentrated under reduced pressure. Purification by flash column chromatography provided 5-methoxy-2,6-dimethyl-4-(2-methylthieno[3,2-b]pyrrol-4-yl)pyridazin-3-one (116 mg, 0.40 mmol, 38 %) as a colourless oil.

1H NMR (400 MHz, COd3): OH. 7.01 (1H, d), 6.52 (1H, d), 6.49 (1H, m), 3.76 (3H, s), 3.32 (3H, a), 2.51 (3H, d), 2.32 (3H, a).

2.3 Preparation of 5-methoxy-2,6-dimethyl-4-(3,5,6-trichloro-2-methyl-thieno [3,2- b]pyrrol-4-yl)pyridazin-3-one & 4-(5,6-dichloro-2-methyl-thieno[3,2-b]pyrrol-4-yl)-5-methoxy-2, 6-dimethyl-pyridazin-3-one To a stirred solution of 5-methoxy-2,6-dimethyl-4-(2-methylthieno[3,2-b]pyrrol-4-yl)pyridazin-3-one (105 mg, 0.36 mmol) in dichloromethane (10 mL) at 0 °C was added a solution of sulfuryl chloride (98 mg, 0.73 mmol) in dichloromethane (2 mL) dropwise over 30 mm via syringe pump. After the addition was complete, the reaction was stirred for a further 20 mm at 0 °C. The reaction was quenched with saturated aqueous sodium bicarbonate solution (10 mL). After stirring for 10 mm, the mixture was passed through a phase separator cartridge.

The dichloromethane layer was concentrated under reduced pressure. Purification by flash column chromatography provided 4-(5,6-dichloro-2-methyl-thieno[3,2-b]pyrrol-4-yl)-5-methoxy- 2,6-dimethyl-pyridazin-3-one (80 mg, 0.22 mmol, 62%) as a white solid.

CI 0 -

I NMR data for 4-(5,6-Dichloro-2-methyl-thieno[3,2-b]pyrrol-4-yl)-5-methoxy-2, 6-dimethyl-pyridazin-3-one: 1H NMR (CDCI3) 6H 6.41 (1H, q), 3.74 (3H, s), 3.51 (3H, s), 2.49 (3H, d), 2.31 (3H, s).

Further elution provided 5-methoxy-2,6-dimethyl-4-(3,5,6-trichloro-2-methyl-thieno[3,2-b] pyrrol-4-yl)pyridazin-3-one (16 mg, 0.042 mmol, 11 %) as a white solid.

CI

CI

T

N MR data for 5-methoxy-2,6-dimethyl-4-(3,5,6-trichloro-2-methyl-thieno[3,2-b] pyrrol-4-yl)pyridazin-3-one: 1H NMR (Cod3) 6H 3.73 (3H, s), 3.62 (3H, s), 2.41 (3H, s), 2.32 (3H, s).

2.4 Production of 2,6-Dimethyl-4-(3,5,6-trichloro-2-methyl-thieno[3,2-bjpyrrol-4-yl) pyridazine-3,5-dione A solution of 5-methoxy-2,6-dimethyl-4-(3,5,6-trichloro-2-methyl-thieno[3,2-b] pyrrol-4-ypyridazin-3-one (14 mg, 0.036 mmol) in morpholine (2 mL) was heated in a microwave at °C for 1 mm. The reaction was concentrated under reduced pressure to remove most of the morpholine. The residue was taken up in dichloromethane (20 mL) and 1M aqueous citric acid solution (20 mL). After stirring for 5 mm, the mixture was passed through a phase separator cartridge. The dichioromethane layer was concentrated under reduced pressure to provide 2,6-dimethyl-4-(3,5,6-trichloro-2-methyl-thieno[3,2-b]pyrrol-4-yl) pyridazine-3,5-dione (13 mg, 0.034 mmol, 94%) as a pale yellow solid. Cl Cl

H NMR (400 MHz, DM50-cl6) 6H* 3.58 (3H, s), 2.40 (3H, s), 2.27 (3H, s).

Compounds 1.001 to 1.003 as shown in Table 1 above! were made using the methodology described above in Examples 1 and 2. Physical data for these compounds is shown below in Table 2.

Table 2 NMR data for compounds of the invention Compound NMR data 1.001 1H NMR (400 MHz, MeOH-d4) O: 2.44 (3H, s), 3.76 (3H, s), 7.10 (2H, d), 7.27 (2H, t), 7.41 (2H, t), 8.14 (2H, d).

1.002 IH NMR (400 MHz, DMSO-d6) oH: 6.62 (1H, q), 3.58 (3H, s), 2.46 (3H, d), 2.26 (3H, s).

1.003 1H NMR (400 MHz, DMSO-d6) O: 3.58 (3H, s), 2.40 (3H, s), 2.27 (3H, s).

BIOLOGICAL EXAMPLES

BI Post-emergence efficacy Seeds of a variety of test species are sown in standard soil in pots:-Solanum nigrum (SOLNI), Amaranthus retoflexus (AMARE), Setaria faber! (SETFA), Alopecurus myosuroides (ALOMY), Echinoch/oa crus-galli (ECHCG), Ipomoea hederacea (IPOHE). After 8 days cultivation (post-emergence) under controlled conditions in a glasshouse (at 24/16°C, day/night; 14 hours light; 65% humidity), the plants are sprayed with an aqueous spray solution derived from the formulation of the technical active ingredient in acetone/water (50:50) solution containing 0.5% Tween 20 (polyoxyethelyene sorbitan monolaurate, CAS RN 9005-64-5).

S Compounds are applied at 1000 g/ha. The test plants are then grown in a glasshouse under controlled conditions in a glasshouse (at 24/16°C, day/night; 14 hours light; 65 % humidity) and watered twice daily. After 13 days. the test is evaluated for the percentage damage caused to the plant. The biological activities are shown below in Table 3, on a five point scale (5 = 80- 100%; 4 = 60-79%; 3=40-59%; 2=20-39%; 1=0-19%).

Table 3 Control of weed species by compounds of formula (I) after post.emergence application at a rate of I 000g/Ha Compound No. SOLNI AMARE SETFA ALOMY ECHCG IPOHE 1.001 5 5 1 1 3 5 1.002 5 4 1 1 1 5 1.003 5 5 1 1 1 5

Claims (22)

1. CLAIMSA compound of formula (I) o N-. [X]R G(I) or a salt or N-oxide thereof, wherein R1 is selected from the group consisting of C1-C4 alkyl, Ci-C2alkoxy-C1-C2 alkyl, C2-C4 alkenyl, 01-04 haloalkyl, 02-04 haloalkenyl, 02-04 alkynyl and 02-04 haloalkynyl; R2 is selected from the group consisting of hydrogen, halogen, cyano, C1-C6alkyl, C1- C6haloalkyl, C1-C6haloalkoxy, Ci-C3haloalkoxy-Ci-C3alkyl-, Ci-C6alkoxy, Ci-C3alkoxy-Ci-C3alkyl, Ci-C3alkoxy-Ci-C3alkoxy-Ci-C3alkyl-, C3-C5cycloalkyl, C2-C6 alkenyl, C2-C6 haloalkenyl, C2-C6 alkynyl, Ci-Cehydroxyalkyl-, Ci-C6alkylcarbonyl-, -S(O)Ci-C6alkyl, amino, Ci-O6alkylamino, Ci-C6dialkylamino, -C(Ci-C3alkyl)=N-O-Ci-O3alkyl and 02-06 haloalkynyl; R4 is hydrogen, hydroxyl or halogen, R6 is hydrogen or halogen; or, R4 and R5 together with the carbon atoms to which they are joined form a 5-or 6-membered optionally substituted aryl or heteroaryl ring; o is a 5-or 6-membered awl or heteroaryl ring; each X is independently, hydroxyl, halogen, nitro, cyano, amino, C1-C6 alkyl, C1-C6haloalkyl, C3-C6cycloalkyl, C1-C6 alkoxy, C1-C6alkoxyl carbonyl or -S(O)C1-C6alkyl, G is hydrogen or -C(O)-R6; R6 is selected from the group consisting of C1-C6alkyl, C1-C6alkenyl, C1-C5alkynyl, C1-O6alkyl-S-, Ci-C6alkoxy, -NR'R8 and phenyl optionally substituted by one or more R' and R8 are independently selected from the group consisting of C1-C6 alkyl, C1-C6 alkoxy-; or R' and R° can together form a morpholinyl ring; R9 is selected from the group consisting of halogen, cyano, nitro, C1-C3alkyl, C1-O3haloalkyl, C1-O3alkoxy and C1-O3haloalkoxy; n = 0,1,2,3 or 4; p0,lor2, provided that when 0 is a 6-membered aromatic ring and R6 is chlorine or bromine, R4 is hydroxyl, fluorine or iodine.
2. 2. A compound according to claim 1, wherein G is hydrogen.
3. 3. A compound according claim 1 or claim 2, wherein R2 is selected from the group consisting of hydrogen! Gi-C6alkyl, Gi-C6haloalkyl, Ci-C6alkoxy, Gi-C3alkoxy-Ci-C3alkyl.

   C3-Cecycloalkyl, C2-C6alkenyl, C2-C6haloalkenyl, C2-C6 alkynyl and C2-C6haloalkynyl;
4. 4. A compound according to claim 3, wherein S2 is selected from the group consisting of hydrogen, methyl, ethyl, cyclopropyl and methoxymethyl.
5. 5. A compound according to any one of the previous claims, wherein R2 is methyl.
6. 6. A compound according to any one of the previous claims, wherein 1 is selected from the group consisting of methyl, ethyl and n-propyl.
7. 7. A compound according to any one of the previous claims, wherein 4 and 5 are independently hydrogen or halogen.
8. 8. A compound according to claim 7, wherein 4 and 5 are independently hydrogen or chlorine.
9. 9. A compound according to any one claims 1-6, wherein 54 and 5 together with the carbon atoms to which they are joined form a 6-membered aryl ring, optionally substituted by 1-3 groups Y, wherein each Y is independently hydroxyl, halogen, nitro, cyano, amino, CrC6 alkyl, C1-C6haloalkyl, C3-C6cycloalkyl, C1-C6 alkoxy, C1-C5alkoxyl carbonyl or -S(O)C1-C6alkyl, and p is as defined in claim 1.
10. 10. A compound according to claim 9, wherein each Y is independently hydroxyl, halogen, C1-C3alkyl, C1-C3alkoxy, C1-C3haloalkyl, or C1-C3haloalkoxy.
11. 11. A compound according to claim 10, wherein each Y is halogen.
12. 12. A compound according to claim 9, wherein 4 and 6 together with the carbon atoms to which they are joined form an unsubstituted phenyl ring.
13. 13. A compound according to any one of the previous claims, wherein Q is a phenyl, thienyl, furyl, thiazolyl, imidazolyl, oxazolyl, pyrazolyl, or triazolyl ring.
14. 14. A compound according to claim 13, wherein 0 is a phenyl orthienyl ring.
15. 15. A compound according to any one of the previous claims wherein n is an integer or 0, 1, or2.
16. 16. A compound according to any one of the previous claims wherein X is hydroxyl, halogen, Ci-C6alkyl, C1-C6haloalkyl, Ci-Calkoxy, or C1-C6haloalkoxy.
17. 17. A compound of formula (1)RNcy.... [)q R (1), wherein R1, R2, R4, R5, 0, X, and n are as defined in claim 1.
18. 18. A herbicidal composition comprising a herbicidal compound according to any one of claims 1-16 and an agriculturally acceptable formulation adjuvant.
19. 19. A herbicidal composition according to claim 18, further comprising at least one additional pesticide.
20. 20. A herbicidal composition according to claim 19, wherein the additional pesticide is a herbicide or herbicide safener.
21. 21. A method of controlling unwanted plant growth, comprising applying a compound of formula (I) as defined in any one of claims 1 to 16, or a herbicidal composition according to any one of claims 18 to 20, to the unwanted plants or to the locus thereof.
22. 22. Use of a compound of Formula (I) as defined in any one of claims 1 to 16 as a herbicide.