GB2189238A

GB2189238A - Heterocyclic phenyl ether compounds

Info

Publication number: GB2189238A
Application number: GB08609155A
Authority: GB
Inventors: David Munro; Rino Antonio Bit
Original assignee: SHELL INT RESEARCH; Shell Internationale Research Maatschappij BV
Current assignee: SHELL INT RESEARCH; Shell Internationale Research Maatschappij BV
Priority date: 1986-04-15
Filing date: 1986-04-15
Publication date: 1987-10-21
Also published as: GB8609155D0

Abstract

Benzoazine phenyl ether compounds of the general formula I and N-oxides, salts or inner salts thereof, <IMAGE> in which n is 0, 1, 2 or 3; A, which may be the same or different when n is greater than 1, represents a halogen atom or a cyano, nitro, alkyl or haloalkyl group; and Het represents certain 6-quinolinyl, 6- quinazolinyl, 6-quinoxalinyl, 6-cinnolinyl, 6-(1 ,2,3-benzotriazinyl) and 6-(1,2,4-benzotriazinyl) groups (with substitution patterns defined in the specification), are novel herbicides.

Description

SPECIFICATION Heterocyclic phenyl ether compounds The invention relates to certain heterocyclic phenyl ether derivatives, the preparation of such compounds, herbicidal compositions containing them, and to their use in combating undesired plant growth.

Various diphenyl ethers are known to be effective herbicides, for example bifenox and diclofop as described respectively in UK Patents Nos. 1232368 and 1423006, and also diphenyl ethers in which one ring is fused with a 5-membered heterocyclic ring as described in Applicants' UK Patent Application No. 8426367 (K 1962). It has now been found that useful herbicidal activity is present in diphenyl ethers in which one phenyl ring is fused with a 6-membered heterocyclic ring to form a heteroaromatic ring system.

Accordingly, the present invention provides benzoazine phenyl ether compounds of the general formula I and N-oxides, salts or inner salts thereof,

in which B represents a hydrogen or halogen atom, A' represents a hydrogen or halogen atom or an alkyl or haloalkyl group, and each of A2 and A3 independently represents a hydrogen or halogen atom or an alkyl, haloalkyl, nitro or cyano group, provided that B must represent a halogen atom when A', A2 and A3 all represent hydrogen atoms;; and X represents a group of formula CR', Y represents a group of formula CR2 and Z represents a group of formula CR3, in which each of R' and R2 independently represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group, or a cyano group, or a group of formula COR4, C02R4 or SO2R4 represents an optionally substituted alkyl, alkenyl, cycloalkyl, aryl or aralkyl group, and R3 represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group; or X represents a group of formula CR5, Y represents a nitrogen atom and Z represents a group of formula CR in which each of R5 and R6 independently represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group, or R5 represents a hydrogen atom or an optionally substituted alkyl group and R6 represents a halogen atom or a cyano group or an optionally substituted alkoxy, alkylthio, alkylcarbonyl, alkoxycarbonyl or amino group; or X represents a group of formula CR7, Y represents a group of formula CR8 and Z represents a nitrogen atom, in which one of R7 and R8 represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group and the other represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group, or a halogen atom or a cyano group, or an optionally substituted alkoxy, alkylthio, alkylcarbonyl, alkoxycarbonyl or amino group, or R7 represents an amino group and R8 represents a cyano group or an optionally substituted alkoxycarbonyl group; or X represents a nitrogen atom, Y represents a group of formula CH and Z represents a group of formula CR9, in which R9 represents a hydrogen or halogen atom or an optionally substituted alkyl, alkenyl, cycloalkyl, aryl or aralkyl group, or a hydroxy or cyano group, or an optionally substituted amino, alkoxy, alkylthio, alkylsulphonyl, arylsulphonyl, alkylcarbonyl or alkoxycarbonyl group; or X and Y both represent nitrogen atoms and Z represents a group of formula CR'O in which R'O represents a hydrogen or halogen atom or a cyano group, or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl, aralkyl, alkoxy, alkylthio, amino, alkylcarbonyl, alkoxycarbonyl or alkylsulphonyl group; or X and Z both represent nitrogen atoms and Y represents a group of formula CR" in which R" represents an optionally substituted amino group.

Generally, when any of the above mentioned variables represents an alkyl group or a group which contains an alkyl moiety, this alkyl group or moiety may be linear or branched and may suitably contain 1 to 10, preferably 1 to 6, and most preferably 1 to 4 carbon atoms, suitable examples being methyl, ethyl and propyl. When they represents a cycloalkyl group this may suitably contain from 3 to 10, preferably 5 to 8, carbon atoms, and is suitably cyclohexyl. An alkenyl group preferably has 2 to 6 carbon atoms. An aryl group is preferably phenyl, and an aralkyl group, benzyl. When any of the foregoing is designated as being optionally substituted, the substituent groups which are present may be any of those customarily employed in the development of pesticidal compounds, and/or the modification of such compounds to influence their activity, persistence, penetration or other property.In relation to alkyl, aikenyl or cycloalkyl moities, specific examples of substituents include halogen, especially chlorine, atoms and nitro, cyano, amino, hydroxyl, C14 alkoxy, especially methoxy, C14 haloalkoxy, or ester, e.g. (C, 4al- koxy) carbonyl, groups. It is preferred, however, that alkyl, alkenyl or cycloalkyl moieties in compounds of formula I are unsubstituted. In the case of an aryl moiety, this may be unsubstituted or have for example from 1 to 3 substituents, preferably selected independently from halogen atoms, especially chlorine, and nitro, cyano, amino, hydroxyl, C, @ alkyl and substituted C14 alkyl (especially haloalkyl, such as trifluoromethyl) groups.

In the case of an optionally substituted amino group, substituents are preferably independently selected from alkyl phenyl and amino groups, and groups of formula -N=CR12R'3 where each of R12 and R13 independently represents a hydrogen atom or an alkyl group.

Preferably A' is a haloalkyl, especially trifluoromethyl, group, A2 is a halogen, especially chlorine, atom or a nitro or cyano group and A3, is a halogen, especially chlorine atom or, more preferably, a hydrogen atom.

Suitably, R' represents an optionally substituted C14 alkyl group or an optionally substituted (C, 4 alkoxy) carbonyl group, preferably an unsubstituted C14 alkyl or (C1 4 alkoxy) carbonyl group. Especially preferred are methyl, ethyl methoxycarbonyl or ethoxycarbonyl groups. R2 preferably represents an optionally substituted (C14 alkoxy) carbonyl group, preferably unsubstituted, especially methoxycarbonyl or ethoxycarbonyl. It is preferred that R3 represents an optionally substituted C14 alkyl group, preferably unsubstituted, and especially methyl or ethyl.

Considering now the moieties R5 and R6, it is preferred that R5 is selected from hydrogen and optionally substituted C14 alkyl, (preferably unsubstituted C14 alkyl such as methyl or ethyl), and R6 is selected from hydrogen, optionally substituted C14 alkyl (preferably unsubstituted, such as methyl or ethyl) and C14 alkoxy, preferably methoxy or ethoxy.

Preferably, each of R7 and R8 independently represents a hydrogen atom or an optionally substituted C14 alkyl or aryl group. Of these groups, unsubstituted C14 alkyl or aryl groups, such as methyl, ethyl and phenyl are preferred.

Suitably, R9 represents a hydrogen or halogen atom or a C1-4 alkyl group or a hydroxy or cyano group, or an amino group which is optionally substituted by one or two moieties selected independently from hydrogen atoms,. C14 alkyl groups, amino groups and groups of formula -N=CR12R13 where each of R12 and R13 independently represents a hydrogen atom or a C14 alkyl group, or R9 represents an C14 alkylsulphonyl, optionally substituted phenylsulphonyl, C1-4 alkylthio, or optionally substituted C14 alkoxy group. When said phenylsulphonyl group is substituted it is preferably substituted by a halogen atom or a C1-4 alkyl group, especially a methyl group.

When said optionally substituted C14 alkoxy group is substituted it it preferably substituted by an (C, 4alkoxy) carbonyl group. Of these possible groups, preferred are methoxy or ethoxy, optionally substituted by a methoxycarbonyl or ethoxycarbonyl group.

R10 preferably represents an optionally substituted C14 alkyl or C14 alkoxy group. Preferably, R10 is unsubstituted. Methyl, ethyl, methoxy and ethoxy groups, are very suitable.

Preferred compounds of formula I are quinazolines, quinoxalines, cinnolines and, especially, 1,2,3-benzotriazines. More specifically, compounds of the general formula I which are considered as preferred sub-classes on account of their herbicidal activity fall into the following categories: X represents a group CH, Y represents a nitrogen atom and Z represents a group CR6 where R6 is a C14 alkyl group, preferably a methyl group; each of X and Y represents a CH group an Z represents a nitrogen atom;X represents a nitrogen atom, Y represents a CH group and Z represents a group CR9 where R9 represents a C14 alkyl or C1-4 alkoxy group, preferably a methyl or methoxy group; and each of X and Y represents a nitrogen atom and Z represents a group of formula CR10 where R10 represents a C1-4 alkyl or C1-4 alkoxy group, especially a methyl or methoxy group; together with their N-oxides.

It appears to be the case that herbicidal activity is shown by compounds of formula I substantially independently of whether they are as drawn under formula I or whether they are in the form of N-oxides, salts and inner salts. Interesting activity has been shown by 3-N-oxides of quinazolines, and by 1 ,2,3-benzotriazines, whether in the form of their 3-N-oxdes, or 2-N-oxides, or unoxidized.

The invention also provides for the preparation of a compound of the general formula I as defined above. In the following statement the use of a variable carrying only a superscript, (for example R3), indicates that the moieties that that variable represents correspond to the moieties it represents in the foregoing definition of compounds of the invention, whilst the use additionally of subscripts denotes that the subscripted variable, (for example R3A), is used to represent a sub-class of moieties within the class R3 as defined in the foregoing definition of compounds.

The moiety Q used below represents a halogen atom or a nitro group or a group of formula -OM where M represents a hydrogen or alkali metal atom or a group of formula

The process according to the invention comprises reacting a compound of formula II with a compound of formula III

where one of the moieties R1A and R2A represents an optionally substituted alkoxycarbonyl or aryloxycarbonyl group and the other represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, aryl, aralkyl, alkoxycarbonyl or aryloxycarbonyl group, and RA represents an alkyl, cycloalkyl or optionally substituted aryl group; or reacting a compound of formula IV with a compound of formula V

or reacting a compound of formula VI with ammonia

where each of R5A and R6A independently represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group; or reacting a compound of formula VII with a compound of formula Vlil

where each moiety R'4 represents an alkyl group, R5 represents a hydrogen atom or an optionally substituted alkyl group, and R69 represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group, or a cyano group, or an optionally substituted alkoxy, alkoxy, alkylthio, alkoxycarbonyl or amino group; or halogenating a compound of formula IX

where R5c represents a hydrogen atom or an optionally substituted alkyl group, to produce a compound of formula I in which R6 is a halogen atom, and optionally converting the halogen substituent R9 Of the resulting compound of formula I into a cyano group or an optionally substituted alkoxy, alkylthio, alkylcarbonyl, alkoxycarbonyl or amino group; or reacting a compound of formula X with a compound of formula Xl, or with a polymeric derivative thereof,

where each of R7A and R8A independently represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group; or halogenating a compound of the general formula XII or XIII

in which the moiety R75 or R85 represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group, and optionally converting the halogen substituent R7 or R8 of the resulting compound of formula I into a cyano group or an optionally substituted alkoxy, alkylthio, alkylcarbonyl, alkoxycarbonyl or amino group; or reacting a compound of formula XIV with a compound of formula XV

where each of R7C and R8C independently represents a hydrogen atom or an optionally substituted alkyl, alkenyl, cycloalkyl, aryl or aralkyl group; or reacting a compound of formula XIV with malononitrile to form a compound of formula I in which R7 is an amino group and R8 is a cyano group, and optionally converting the cyano group into an optionally substituted alkoxycarbonyl group; or diazotising a compound of the formula XVI

where R9A represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group; or diazotising a compound of formula XVII

to produce a compound of formula I in which R9 is a hydroxy group, and optionally converting that compound into a compound of formula I in which R9 is a halogen atom or a cyano group, or an optionally substituted amino, alkoxy, alkylthio, alkylsulphonyl, arylsulphonyl, alkylcarbonyl or alkoxycarbonyl group; or diazotising a compound of formula XVIII

in which R1 represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group, a cyano group, or an optionally substituted alkoxy, alkylthio, alkylcarbonyl, alkoxycarbonyl or amino group; or by S-alkylation of a compound of formula XIX

to produce a compound of formula I in which R'O is an optionally substituted alkylthio group, and optionally converting that compound to a compound of formula I in which R'O is a halogen atom or a cyano group or an optionally substituted alkoxy, amino, alkylcarbonyl, alkoxycarbonyl group or alkylsulphonyl group; or reacting a compound of formula XX with optionally substituted cyanamide

to produce a compound of formula I in which R" represents an optionally substituted amino group; and, when any of the above steps yields a compound in which Q does not represent a group of formula

reacting said compound with a compound of formula XXI

in which compound W represent a halogen atom or a nitro group when Q represents a group -OM' where M' represents a hydrogen or alkali metal atom, and W represents such a group -OM' when Q represents a halogen atom or a nitro group; and optionally converting any product to an N-oxide or reducing any N-oxide formed, and optionally converting any product to a salt or inner salt.

In general, the reactions preferably take place in the presence of a solvent, especially an organic solvent. Suitable solvents generally include hydrocarbons, for example benzene, toluene and xylene, halogenated hydrocarbons, for example carbon tetrachloride and dichloromethane, alcohols, for example ethanol, methanol or ethane-1,2-diol, ethers, for example tetrahydrofuran, acids, for example acetic acid, sulphoxides, for example dimethylsulphoxide, amides, such as N,N-dimethylformamide, and amines, for example pyridine, piperidine and triethylamine.

The reaction between compounds of formulae II and III preferably takes place in an organic solvent, preferably a hydrocarbon such as benzene or an alkylated benzene compound such as toluene or xylene. The reaction may suitably be effected at O to 1 50"C, preferably at an elevated temperature, for example 50 to 125"C, and preferably at the reflux temperature.

The reaction between compounds of formula IV and V may take place in a basic or acidic environment but preferably takes place in an acidic environment, suitably in a strong mineral acid, such as concentrated sulphuric acid. The reaction is suitably effected at O to 150"C, preferably at an elevated temperature, such as 50 to 1 250C, and conveniently at the reflux temperature. An organic acid such as acetic acid is preferably present The reaction of compounds of formula VI with ammonia preferably takes place in an organic solvent, suitably a hydrocarbon, alcohol or ether. The reaction may suitably be effected at O to 1500C, preferably an elevated temperature such as 50 to 1250C, and conveniently the reflux temperature. Preferably, ammonia gas is bubbled into the solution.

The reaction between compounds of formula VII and VIII preferably takes place in an organic solvent, for example an alcohol. An organic or inorganic base may be present. The reaction may be effected at O to 150"C, preferably at an elevated temperature such as 50 to 125"C, and conveniently at the reflux temperature. The compounds of formula I produced are in the form of the 3-N-oxides.

The halogenation of compounds of formulae IX, XII and XIII preferably takes place under standard conditions, using for example a thionyl halide, a phosphorus oxyhalide, a phosphorus pentahalide or a mixture thereof. Chlorides, bromides or iodides are preferred. An organic solvent can be employed if desired and reaction preferably takes place at an elevated temperature, suitably 30 to 120"C, conveniently at the reflux temperature, and preferably under an inert atmosphere. The halogen atom may then be replaced, if desired, by an optionally substituted alkoxy, alkylcarbonyl, alkylthio group or a cyano group, suitably by contact with a corresponding alcohol, alkanoylating agent, thioalcohol, metal alkoxide or thioalkoxide, or cyanide.A suitable temperature range is -10 to 1200C. A temperature of 10 to 30"C is preferred and ambient temperature is most convenient. It may also be converted to a amino group by known methods.

A cyano group may moreover be readily converted to an alkoxycarbonyl group in a known manner, involving hydrolysis and esterification.

The reaction of compounds of formulae X and XI preferably takes place in an aqueous solvent, for example an aqueous solution of a metal hydroxide, or in an organic solvent, suitably an alcohol, and suitably at a temperature of from 0 to 1 500 C, preferably at an elevated temperature such as 50 to 125"C, and conveniently the reflux temperature. The polymeric derivative glyoxal trimeric dihydrate is preferably employed when a compound of formula I in which R7 and R8 are both hydrogen atoms is desired.

The reaction between compounds of formula XIV and XV preferably takes place at an elevated temperature, suitably 25 to 1200C, in an organic solvent such as an alcohol or ether. The enamine compound XV is preferably generated in situ by reaction of an amine with a compound of formula XV'

Ammonia is suitable and may conveniently be bubbled into the reaction mixture.

The reaction between a compound of formula XIV and malononitrile preferably takes place in the presence of an organic solvent such as an amide, suitably N,N-dimethyl-formamide. A base, suitably an amine base such as triethylamine, may advantageously be present. The reaction may be effected at - 10 to 100"C, suitably 0 to 40"C, and preferably at ambient temperature.

The diazotisation of a compound of formula XVI may employ standard conditions. Preferably an alkali or alkaline earth metal nitrite is employed, in the presence of a strong acid such as concentrated sulphuric or hydrochloric acid. The reation mixture is kept at a low temperature, suitably -10 to 20"C, preferably 0 to 5"C. An organic co-solvent such as an alcohol may advantageously be present. Similar conditions are employed for the diazotisation of a compound of formula XVII. The resulting compound in which R9 is a hydroxy group may be converted to a compound in which R9 is a halogen atom, preferably by means of a phosphoryl halide. The reaction preferably takes place at an elevated temperature, such as 50 to 125"C, and preferably at the reflux temperature.The halogen atom may then be displaced in a number of reactions, to yield further compounds of the general formula I. For example, reaction with a compound M+(R9B)- where M is an alkali metal and R9B is an optionally substituted alkoxy group may readily be effected, preferably in an organic solvent and preferably at an elevated temperature, for example, 50 to 125"C suitably the reflux temperature. Aiternatively it may be reacted with a compound M+(R9c)- where R9c is an optionally substituted alkylthio group, in an organic solvent, suitably benzene, toluene or xylene, at elevated temperature, (for example, 50 to125 C), suitably the reflux temperature. Simiiar conditions may be used to prepare from the halo compound an optionally substituted alkylsulphonyl or arylsulphonyl analogue. Alternatively these compounds may be prepared by oxidation of an alkylthio derivative, for example using potassium permanganate, suitably in an alcohol at a temperature - 10 to 50"C, preferably 10 to 30"C, for example, ambient temperature.A corresponding cyano compound may be prepared by reacting a sulpho nyl analogue with a metal cyanide in an organic solvent, such as an alcohol, preferably at an elevated temperature such as 50 to 125"C, suitably the reflux temperature. An optionally substituted alkoxycarbonyl analogue may then be prepared by standard hydrolysis and esterification.

An optionally substituted alkylcarbonyl group may be prepared from the cyano compound by a standard procedure employing a Grignard reagent.

When R9 in a compound of formula I is an optionally substituted amino group (-NRXRY) the compound may be prepared from a compound of formula which R9 is a halogen atom by treatment with a compound of formula HNRXRY, preferably in which an organic solvent such as an alcohol, preferably under an inert atmosphere and preferably at a temperature of - 10 to 60"C, for example 10 to 30"C, and suitably ambient temperature.A hydrazine derivative (one of Rx and RY being an amino group) may readily be converted to a hydrazone group by reaction with a compound Rl2-CO-Rl3, preferably at a temperature - 10 to 50"C, for example 10 to 30"C, and suitably at ambient temperature, with or without use of a solvent.

The diazotization of a compound of formula XVIII preferably takes place under the standard conditions described above for a compound of formula XVI, whereby a 1,2,3-benzotriazine compound of formula I is produced, in the form of its 3-N-oxide.

The S-alkylation of a compound of formula XIX preferably takes place in the presence of a base, and a non-nucleophilic organic solvent and preferably employs a halogenated hydrocarbon as the alkylating agent. The reaction preferably takes place at an elevated temperature, such as 50 to 125"C, and suitably the reflux temperature. The conversion of the compound of formula I in which R10 represents an optionally substituted alkylthio group to such a compound in which R'O represents a halogen atom or a cyano group or an optionally substituted alkoxy, amino, alkylcarbonyl, alkoxycarbonyl or alkylsulphonyl may employ analagous conditions to those described above in relation to the moiety R9. A nucleophilic reagent may be present during the Salkylation of the compound of formula XIX.Thus, for example, the presence of methoxide ions in the reacton mixture enables the compound of formula XIX to produce a compound of formula I in which R'O is methoxy without isolation.

When R'O is a cyano group standard procedures, described earlier, may be employed to convert it to an optionally substituted alkoxycarbonyl group whilst when it is an optionally substituted alkylthio group standard procedures described earlier enable it to be converted to an optionally substituted alkylsulphonyl group.

The reaction between a compound of formula XX and optionally substituted cyanamide preferably takes place in glacial acetic acid, with a concentrated mineral acid also present. The reaction preferably takes place at an elevated temperature, suitably 50 to 150"C and preferably the reflux temperature. A base, suitably an inorganic base, is preferably added.

When the above reactions are effected to make compounds in which Q is other than a group

that is to say, compounds in which one of W and Q represents a halogen, suitably chlorine, atom or nitro group and the other represents a group of formula -OM where M represents a hydrogen atom or alkali metal atom, it is preferably the moiety W which represents the halogen atom or nitro group. The reaction is conveniently carried out by reacting a compound of formula XXI wherein W represents a halogen, suitably chlorine, atom or a nitro group with an alkali metal alkoxide compound produced by reacting the product of any of the above-mentioned reactions in which product Q represents hydroxy, with an alkali metal hydroxide in an alkanol, solvent, for example, ethanol.The reaction of the alkoxide with the compound XXI is preferably carried out in a suitable solvent, for example, dimethyl sulphoxide, sulpholane, dimethyl formamide, or dimethyl acetamide at elevated temperature, conveniently under reflux, and also under an inert atmosphere such as nitrogen.

It is preferred, however, to effect the above reactions with starting materials in which 0 represents a group

so that a further step to produce compounds of formula I is not required.

Some of the above reactions produce compounds of formula I as N-oxides and standard methods may be employed, if desired, to reduce them. N-oxidation techniques are also well known. Suitably, N-oxides are produced in using metachloroperbenzoic acid. The reaction preferably takes place in an organic solvent, preferably of low boiling-point, suitably a halogenated lower alkane such as dichloromethane. The temperature is suitably 10 to 30"C, preferably ambient temperature. Salt formation is also standard. Typically, an alkyl halide, for example, is added to a compound of formula I in the presence of an organic solvent such as an alcohol, preferably at an elevated temperature such as 50 to 120"C, suitably under reflux. Certain compounds may form inner salts if such conditions are prolonged.

The starting materials of formulae II to XX are known compounds or else may be prepared from known compounds by generally known techniques. In general, nitro derivatives of the phenyl or diphenyl ether compounds are known or readily accessible and the amino analoges which are the starting materials in many of the reactions set out above may be prepared by standard hydrogenation of the nitro compounds. For convenience, certain techniques which may be used are outlined below.

Compounds of formula VI may be prepared by reacting a compound of formula IV with a compound of formula R5A COCI, preferably in an organic base such as pyridine and preferably at below room temperature, suitably in the range 0 to 10 C. A compound of formula IX may be prepared by reaction of a compound of formula XXII

with a compound RsC-CONH2 (for example formamide), preferably at elevated temperature. A compound of formula XII or XIII may be prepared by reacting compounds of formula XXII I and XXIV

A compound of formula XIV is prepared by treatment, suitably at ambient temperature, of a compound formula XXV

with an aqueous alcohol saturated with an alkali hydroxide and containing sodium hypochlorite.

A compound of formula XIX may be prepared from a compound of formula XXVI

by diazotisation and treatment with phosphorus pentasulphide, in either order.

The compounds of general formula I have been found to show interesting activity as herbicides. Accordingly, the invention further provides a herbicidal composition comprising a compound of formula I as defined above in association with at least one carrier, and a method of making such a composition comprising a compound of formula I as defined above in association with at least one carrier, and a method of making such a composition which comprises bringing a compound of formula I into association with at least one carrier.

The invention also provides the use of such a compound or composition according to the invention as a herbicide. Further, in accordance with the invention there is provided a method of combating undesired plant growth at a locus by treating the locus with a compound or composition according to the invention. Application to the locus may be pre-emergence or postemergence. The dosage of active ingredient used may, for example, be from 0.05 to 4kg/ha. A carrier in a composition according to the invention is any material with which the active ingredient is formulated to facilitate application to the locus to be treated which may for example be a plant, seed or soil, or to facilitate storage, transport or handling.A carrier may be a solid or a liquid, including a material which is normally gaseous but which has been compressed to form a liquid, and any of the carriers normally used in formulating herbicidal compositions may be used.

Preferably compositions according to the invention contain 0.5 to 95% by weight of active ingredient.

Suitable solid carriers include natural and synthetic clays and silicates, for example natural silicas such as diatomaceous earths; magnesium silicates, for example talcs; magnesium aluminium silicates, for example attapulgites and vermiculites; aluminium silicates, for example kaolinites, montomorillonites and micas; calcium carbonate, calcium sulphates; ammonium sulphate; synthetic hydrated silicon oxides and synthetic calcium or aluminium silicates; elements, for example carbon and sulphur; natural and synthetic resins, for example coumarone resins, polyvinyl chloride, and styrene polymers and copolymers; solid polyvinyl chloride, and styrene polymers and copolymers; solid polychlorophenols; bitumen, waxes; and solid fertilisers, for example superphosphates.

Suitable liquid carriers include water; alcohols, for example isopropanol and glycols; ketones, for example acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethers; aromatic or araliphatic hydrocarbons, for example benzene, toluene and xylene; petroleum fractions, for example kerosine and light mineral oils; chlorinated hydrocarbons, for example carbon tetrachloride, perchloroethylene and trichloroethane. Mixtures of different liquids are often suitable.

Agricultural compositions are often formulated and transported in a concentrated form which is subsequently diluted by the user before application. The presence of small amounts of a carrier which is a surface-active agent facilitates this process of dilution. Thus preferably at least one carrier in a composition according to the invention is a surface-active agent. For example the composition may contain at least two carriers, at least one of which is a surface-active agent.

A surface-active agent may be an emulsifying agent, a dispersing agent or a wetting agent; it may be nonionic or ionic. Examples of suitable surface-active agents include the sodium or calcum salts of polyacrylic acids and lignin sulphonic acids; the condensation of fatty acids or aliphatic amines or amides containing at least 12 carbon atoms in the molecule with ethylene oxide and/or propylene oxide; fatty acid esters of glycerol, sorbitan, sucrose or pentaerythritol; condensates of these with ethylene oxide and/or propylene oxide; condensation products of fatty alcohol or alkyl phenols, for example moctylphenol or poctylcresol, with ethylene oxide and/or propylene oxide; sulphates or sulphonates of these condensation products; alkali or alkaline earth metal salts, preferably sodium salts, of sulphuric or sulphonic acid esters containing at least 10 carbon atoms in the molecule, for example sodium lauryl sulphate, sodium secondary alkyl sulphates, sodium salts of sulphonated castor oil, and sodium secondary alkyl sulphates, sodium salts of sulphonated castor oil, and sodium alkylaryl sulphonates such as dodecylbenzene sulphonate; and polymers of ethylene oxide and copolymers of ethylene oxide and propylene oxide.

The compositions of the invention may for example be formulated as wettable powders, dusts, granules, solutions, emulsifiable concentrates, emulsions, suspension concentrates and aerosols. Wettable powders usually contain 25, 50 or 75% w of active ingredient and usually contain in addition to solid inert carrier, 3-10% w of a dispersing agent and, where necessary, 0-10% w of stabiliser(s) and/or other additives such as penetrants or stickers. Dusts are usually formulated as a dust concentrate having a similar composition to that of a wettable powder but without a dispersant, and are diluted in the field with further solid carrier to give a composition usually containing 211O% w of active ingredient. Granules are usually prepared to have a size between 10 and 100 BS mesh (1.676-0.152 mm), and may be manufactured by agglomeration or impregnation techniques.Generally, granules will contain 2-75% w active ingredient and 0-10% w of additives such as stabilisers, surfactants, slow release modifiers and binding agents. The so-called "dry flowable powders" consist of relatively small granules having a relatively high concentration of active ingredient. Emulsifiable concentrates usually contain, in addition to a solvent and, when necessary, co-solvent, 10-50% w/v active ingredient, 2-20% w/v emulsifiers and 0-20% w/v of other additives such as stabilisers, penetrants and corrosion inhibitors.Suspension concentrates are usually compounded so as to obtain a stable, nonsedimenting flowable product and usually contain 10-75% w active ingredient, 0.5-15% w of dispersing agents, 0.1-10% w of suspending agents such as protective colloids and thixotropic agents, 0-10% w of other additives such as defoamers, corrosion inhibitors, stabilisers, penetrants and stickers, and water or an organic liquid in which the active ingredient is substantially insoluble; certain organic solids or inorganic salts may be present dissolved in the formulation to assist in preventing sedimentation or as anti-freeze agents for water.

Aqueous dispersions and emulsions, for example compositions obtained by diluting a wettable powder or a concentrate according to the invention with water, also lie within the scope of the invention. The said emulsions may be of the water-in-oil or of the oil-in-water type, and may have a thick 'mayonnaise'-like consistency.

The composition of the invention may also contain other ingredients, for example other compounds possessing herbicidal, insecticidal or fungicidal properties.

The invention is illustrated in the following Examples.

Example I 2,3-Dimethoxycarbonyl-4-methyl-6-(2'-chloro-4'-trifluoromethylphenoxy)quinoline A mixture of 4-(2'-chloro-4'-trifluoromethylphenoxy)-2-acetyl amine (5.0g) and dimethyl acetylenedicarboxylate (2.29) in benzene (50ml) was refluxed for 24 hours. After cooling, the benzene was removed under reduced pressure leaving a yellow oil. Purification by chromatography and recrystallization produced the title compound as yellow crystals (2.39), m.p. 126-8"C.

Analysis Calculated: 55.6% C 3.3% H 3.1% N 55.5% C 3.4% H 3.4% N Example 2 2,3-Dimethoxycarbonyl-4-methyl-6-(2'-chloro-4'-trifluoromethyl phenoxyJquinoline, N-oxide 3-Chloroperbenzoic acid (0.5g) was added to a solution of the title compound of Example 1 (1.29) in dichloromethane (50 ml). The reaction mixture was stirred at room temperature for 2 hours. Purification by chromatography and recrystalization yielded the title compound as colourless crystals (0.79), m.p. 175-6"C.

Analysis Calculated 53.7% C 3.2% H 3.0% N Found 53.6% C 3.3% H 3.2% N Example 3 2,4-Dimethyl-3-ethoxycarbonyl-6-(2'-chloro-4'-trifluoromethylphenyl)-quinoline A solution of 4-(2'-chloro-4'-trifluoromethylphenoxy)-2-acetyl aniline (5.0g) and ethyl acetoacetate (2.09) in glacial acetic acid (20ml) containing concentrated sulphuric acid (0.2ml) was heated under reflux for 4 hours. The reaction mixture was cooled and poured into an ice-cold solution of ammonia in water (80ml). The solution was extracted with chloroform (2 x 100ml). The extracts were washed, dried and evaporated to yield a colourless oil. Purification by chromatography yielded the title compound as a colourless oil (4.39).

Analysis Calculated: 59.5% C 4.0% H 3.3% N Found: 59.8% C 4.3% H 3.6% N Example 4 2,4-Dimethyl-3-ethoxycarbonyl-6-(2'-chloro-4'-trifluoromethylphenoxy)-quinoline, N-oxide The title compound was prepared by the method described in Example 2, m.p. 155-156"C.

Analysis Calculated: 57.3% C 3.9% H 3.2% N Found: 57.3% C 4.1% H 4.0% N Example 5 2,4-Dimethyl-6-(2'-chloro-4'-trifluoromethylphenoxy)quinazoline (a) 4-(2'-Chloro-4'-trifluoromethylphenoxy)-2-acetyl aniline (10.0g) in pyridine (30ml) was cooled to 5"C. Acetyl chloride (2.99) was added dropwise over 15 minutes. The reaction mixture was stirred at room temperature for 121 hours. Water (100ml) was added to the reaction mixture and the mixture extracted with chloroform (2x50ml). The extracts were washed, dried and evaporated. The solid residue was washed with hexane then recrystallized to yield colourless crystals of 4-(2'-chloro-4'-trifluoromethylphenoxy)-2-acetyl acetanilide (4.4g), m. p. 105-7"C.

(b) Ammonia was bubbled through a refluxing solution of the product of Example 5(a) (2.0g) in ethane-1,2-diol (30ml) for 30 minutes. The reaction mixture was cooled and poured into a chloroform: water mixture (1:1, v:v, 250ml). The organic layer was separated and dried. Solvent was removed by evaporation leaving a colourless solid which was recrystallized from ethyl acetate-hexane to yield the title compound as colourless crystals (0.59), m.p. 98-99 C.

Analysis Calculated: 57.8% C 3.4% H 7.9% N Found: 57.5% C 3.7% H 7.6% N Example 6 2,4-Dimethyl-6-(2'-chloro-4'-trifluoromethylphenoxy)quinazoline 3-N-oxide (a) 4-(2'-Chloro-4'-trifluoromethylphenoxy) nitrobenzene-2-acetoxime (20.0g) was dissolved in warm ethanol (c. 250ml), 5% palladium on charcoal (2.0g) was added, with stirring, under a nitrogen atmosphere. A 15% aqueous solution of sodium hypophosphite solution (400ml was added portionwise to the mixture over 2 hour. After complete addition the reaction mixture was filtered and extracted with dichloromethane (2x250ml). The organic extracts were dried and evaporated to leave a yellow oil.Purification by chromatography and recrystallization yielded colourless crystals of 4-(2'-chloro-4'-trifluoromethylphenoxy)aniline-2-acetoxime (8.6g), m.p. 109-110 C.

(b) The product of Example 6(a) (3.09) was refluxed in triethylorthoacetate (10ml) overnight.

After cooling the solvent was evaporated leaving an orange oil.

Chromatographic purification yielded the title compound as a pale yellow oil which solidified (1.89), m.p. 116-8"C.

Analysis Calculated: 55.4% C 3.3% H 7.6% N Found: 55.5% C 3.3% H 7.6% N Example 7 4-Methyl-6-(2'-chloro-4'-trifluoromethylphenoxyJquinazoline, 3-N-oxide The title compound (m.p. 159"C) was prepared by a procedure similar to that described in Example 6.

Analysis Calculated: 54.2% C 2.8% H 7.9% N Found: 54.0% C 3.0% H 8.2% N Example 8 2-Ethyl-4-methyl-6-(2'-chloro-4'-trifluoromethylphenoxy)-quinazoline, 3-N-oxide The title compound (m.p. 102"C) was prepared by a procedure similar to that of Example 6.

Analysis Calculated: 56.5% C 3.7% H 7.3% N Found: 56.3% C 3.7%H 7.9% N Example 9 4-Methoxy-6-(2'-chloro-4'-trifluoromethylphenoxy)quinazoline (a) 4-(2'-Chloro-4'-trifluoromethylphenoxy)aniline-2-carboxylic acid (10.09) in formamide (10ml) were heated, with stirring, at 140 C for 5 hours.After cooling the residue was dissolved in the minimum amount of ethyl acetate and chromatographed, yielding an oil which solidified to a light brown solid (4.39), m.p. 191-4"C, being a compound of formula XXVII

(b) Phosphoryl chloride (50ml) was added to a finely ground mixture of the product of Example 9(a) (4.1 g) and phosphorus pentachloride (2.59). The stirred suspension was refluxed under a nitrogen atmosphere until a clear solution formed (approximately 1 21 hours). The solvent was then removed under vacuum leaving a brown oil comprising 4-chloro-6-(2'-chloro-4'-trifluoromethylphenoxy)-quinazoline, to which was added, dropwise, a solution of sodium (0.49) in methanol (25ml). The reaction mixture was stirred for 1 hour.A water: diethyl ether mixture (1:1, v:v; 200ml) was added to the reaction mixture, the organic layer was separated and dried, and the solvent was evaporated off. The resulting yellow oil was purified by chromatography and recrystallisation to produce the title compound as white crystals (2.29), m.p. 86-8"C.

Analysis Calculated: 54.2% C 2.8% H 7.9% N Found: 53.9% C 2.9% H 8.0% N Example 10 4-Methoxy-6-(2'-chloro-4'-trifluoromethylphenoxyJquinazoline, 1-N-oxide The title compound (m.p. 173"C) was produced by a procedure similar to that described in Example 2.

Analysis Calculated: 51.8% C 2.7% H 7.6% N Found: 51.3% C 2.9% H 7.7% N Example 11 6-(2'-Chloro4'-trifluoromethylphenoxy) quinoxaline 4(2'-Chloro-4'-trifluoromethylphenoxy)-1,2-phenylenediamine (39) and glyoxal trimeric dihydrate (39) were disolved in ethanol (30ml). The reaction mixture was refluxed with stirring for 2 hour.

Chromatographic purification yielded title compound as a colourless oil (2.1 g) Analysis Calculated: 55.5% C 2.5% H 8.6% N Found: 56.0% C 2.9% H 8.0% N Example 12 2,3-Dimethyl-6-(2 '-chloro-4 trifluoromethylphenoxy)quinoxaline The title compound was produced (as colourless crystals, m.p. 87-8"C) by a procedure similar to that described in Example 11 but employing diacetyl instead of glyoxal trimeric dihydrate.

Analysis Calculated: 57.9% C 3.4% H 8.0% N Found: 57.9% C 3.4% H 8.0% N Example 13 2-Phenyl-6-(2 '-chlorn-4 '-trifluornmethylphenoxy)quinoxaline The title compound was produced (as colourless crystals, m.p. 112"C), by a procedure similar to that described in Example 11, but employing phenylglyoxal instead of glyoxal trimeric dihydrate.

Analysis Calculated: 62.9% C 3.0% H 7.0% N Found: 63.0% C 3.0% H 7.0% N Example 14 5-Chloro-6-phenoxy-quinoxaline The title compound was prepared (as a solid, m.p. 70 C) by a procedure similar to that described in Example 11, but employing 4-phenoxy-3-chloro-1,2-phenylenediamine.

Analysis Calculated: 65.5% C 3.5% H 10.9% N Found: 65.5% C 3.5% H 10.9% N Example 15 2,3-Dimethyl-6-(2'-chloro-4'-trifluoromethylphenoxy)-quinoxaline di-N-oxide (a) 4-(2'-chloro-4'-trifluoromethylphenoxy)-2-amino nitrobenzene (3.59) was dissolved in ethanol saturated with potassium hydroxide (50ml). The deep red solution was cooled to 0 C and commercial aqueous sodium hypochlorite was added until the red colour disappeared to give pale yellow crystals. Chromatography and recrystallization yielded off-white crystals (2.5g), m.p.

52 C, of the compound of formula XXVIII

(b) The compound produced in Example 15(a) (3.09) and 2-butanone (0.79) were dissolved in methanol (25ml). Ammonia was bubbled through this stirred solution at 50 C for 4 hours. The reaction mixture was allowed to cool to ambient temperature then filtered. The collected precipitate was washed with ice cold methanol (less than 5ml) and recrystallized to give the title compound as pale red crystals (2.29), m.p. 176-8"C.

Analysis Calculated: 53.1% C 3.10/0 H 7.3% N Found: 53.1% C C 3.3% H H 7.9% N Example 16 2-Amino-3-cyano-6-(2'-chloro-4'-trifluoromethylphenoxy)-quinoxaline, di-N-oxide The compound produced in Example 15(a) (3.0g) and malononitrile (0.5g) were dissolved in dry N,N-dimethylformamide (25ml) under.a nitrogen atmosphere. Triethylamine (0.29) was added.

The reaction mixture was stirred at room temperature for 3 hours. The reaction mixture was filtered and the red crystals collected and washed with 5ml ice cold methanol (1.29, m.p.

265 C-decomposed).

Analysis Calculated: 48.4% C 2.0% H 14.1% N Found: 48.0% C 2.2% H 14.1% N Example 17 4-Hydroxy-6-(2'-chloro-4'-trifluoromethylphenoxy)cinnoline 4-(2'-Chloro-4'-trifluoromethylphenoxy)-2-acetyl aniline (179) was dissolved in acetic acid (15ml). Hydrochloric acid (500ml) was added and the suspension was diazotised by the addition of sodium nitrite (5g) in water (10ml) at 0-5 C. Further hydrochloric acid (200ml) was added and the reaction mixture was allowed to stand for 2 days at ambient temperature. The precipitate was filtered off and dissolved in chloroform. The organic solution was washed with aqueous sodium acetate until neutral, then with water, and the solvent evaporated off to give a pale orange solid. Chromatography followed by recrystallisation yielded the title compound as colourless crystals, (9.89), m.p. 235 C.

Analysis Calculated: 52.9% C 2.4% H 8.2% N Found: 53.0% C 2.4% H 8.2% N Example 18 4-Chloro-6(2'-chloro-4'-trifluoromethylphenoxy)cinnoline The title compound of Example 17 (1 g) was added to phosphoryl chloride (5ml) and refluxed for 1 hour. Diethyl ether (20ml) was added and the reaction mixture made basic with aqueuous sodium hydroxide. The ethereal layer was separated, washed, and dried, the solvent was removed by evaporation and the residue chromatographed to give a colourless oil which solidified. Recrystallisation gave the title compound as colouless crystals (0.85g), m.p, 105"C.

Analysis Calculated: 50.1% C 1.9% H 7.8% N Found: 50.1% C 1.7% H 7.7% N Example 19 4-(lsopropylidenehydrazino)-6-(2 "-chloro-4 '-trifluoromethylphenoxy cinnoline The title compound of Example 18 (5.3g) was suspended in ethanol (30ml) and hydrazine hydrate (1.5g) was added. The reaction mixture was stirred at ambient temperature under a nitrogen atmosphere for 4 days. Ethanol was partially removed by evaporation and a waterchloroform mixture added (50:50, v:v; 500ml). Three further extractions of the aqueous layer were effected, each with 250ml chloroform to obtain an organic phase comprising 4-hydrazino6-(2'-chloro-4'-trifluoromethylphenoxy)-cinnoline.Chloroform was evaporated off under reduced pressure until the volume of the reaction mixture was 250ml. Acetone was added in excess. An instanteous reaction occurred. Purification by chromatography and recrystallization yielded the title compound as yellow crystals (3.79), m.p. 205"C.

Analysis Calculated: 54.5% C 3.6% H 14.2% N Found: 54.8% C 3.6% H 14.3% N Example 20 4-Methylthio-6-(2tchloro-4'-trifluoromethylphenoxy)cinnoline The title compound of Example 18 (29) and sodium methane thiolate (0.49) in benzene (50ml) were refluxed for 48 hours. The reaction mixture was cooled and the solvent removed in vacuo.

Purification by chromatography and recrystallization yielded the title compound as colourless crystals (1.09), m.p. 137-9"C.

Analysis Calculated: 51.8% C 2.7% H 7.6% N Found: 51.7% C 2.9% H 7.6% N Example 21 4-Methoxy-6-(2'-chloro-4 '-trifluoromethylphenoxy)cinnoline The title compound of Example 18 was added to a solution of sodium methoxide (50ml) prepared using 0.49 of sodium. The reaction mixture was refluxed, with stirring, under a nitrogen atmosphere, for 1 hour. The solvent was removed by evaporation until the reaction mixture had halved in volume and the mixture was extracted with chloroform, separate, washed, dried and purified by chromatography and recrystallization, leaving the title compound as colourless crystals (29), m.p. 1300C.

Analysis Calculated: 54.2% C 2.8% H 7.9% N Found: 53.7% C 2.9% H 7.9% N Example 22 2-Methyl-4-methoxy-6-(2'-chloro-4'-trifluoromethylphenoxy)cinnolinium iodide The title compound of Example 21 (2.59) was dissolved in warm ethanol (100mix, and methyl iodide (30ml) was added. The reaction mixture was refluxed for 3 hours and then allowed to stand overnight. The solvent was removed by evaporation, leaving an orange gum which was purified by recrystallisation to yield the title compound as orange crystals (0.3g), m.p. 114 C.

Analysis Calculated: 45.4% C 2.9% H 6.2% N Found: 44.5% C 2.9% H 5.8% N Example 23 inner salt of the title compound of Example 21 Further recystallisation of the title compound of Example 22, from an ethanol-hexane mixture, produced the title compound, m.p.168 C.

Analysis Calculated: 54.2% C 2.8% H 7.9% N Found: 54.1% C 3.0% H 7.9% N Example 24 2-N-oxide of the title compound of Example 21. (m.p. 190"C) Analysis Calculated: 51.8% C 2.8% H 7.6% N Found: 51.8% C 2.7% H 7.6% N Example 25 1-N-oxide of the title compound of Example 21 (m.p. 162"C) Analysis Calculated: 51.8% C 2.8% H 7.6% N Found: 51.8% C 2.7% H 7.6% N The title compounds of Examples 24 and 25 were prepared by treatment of the title compound of Example 21 in a manner substantially as described in Example 2, followed by chromatography separation.

Example 26 4-Methyl-6-(2'-chloro-4 '-trifluoromethylphenoxyJcinnoline (a) Methyl triphenyl phosphonium iodide (9g) was added to dry tetrahydrofuran (50ml) and nbutyl lithium was added, with stirring, under a dry nitrogen atmosphere, at -300C. After 2 hour 4-(2'-chloro-4'-trifluoromethylphenoxy)nitrobenzene-2-carboxaldehyde (9.09) in tetrahydrofuran (20mi) was added dropwise. After addition was complete the reaction mixture was allowed to rise to room temperature.The solvent was removed by evaporation, the residue extracted, dried, solvent was evaporated, and the residue was purified by chromatrogaphy, yielding 4-(2'-chloro4'-trifluoromethylphenoxy)-2-isopropenyl nitrobenzene as a light brown oil which solidified. (6.09), m.p.1 140C.

(b) 4-(2'-Chloro-4'-trifluoromethylphenoxy)-2-isopropenyl nitrobenzene (129) was dissolved in warm ethanol (100ml). 5% Palladium on charcoal (1.29) was added with stirring under a nitrogen atmosphere. 12% Aqueous sodium hypophosphite solution was added to the reaction mixture until reaction was complete. The reaction mixture was filtered, and extracted with dichloromethane (2x 100ml). The organic extracts were dried and solvent was removed by evaporation yielding a yellow oil which was purified by chromatography, producing 4-(2'-chloro-4'-trifluoromethyl phenoxy)-2-isopropenyl aniline as a yellow oil (3.0g). This compound was dissolved in the minimum amount of glacial acetic acid.An ice cold mixture of concentrated hydrochloric acid (5.0ml) and water (10.0ml) was added. The reaction mixture was cooled to 0-5"C and a solution of sodium nitrite (0.639) in water (2ml) was added dropwise over 10 minutes. After addition was completed the reaction mixture was allowed to stand for 2 hour then extracted with chloroform. Extracts were washed and dried and solvent was evaporated leaving a dark red oil which was purified by chromatography and recrystallisation, to yield the title compound as yellow crystals (0.9g), m.p. 112-4"C.

Analysis Calculated: 56.7% C 3.0% H 8.3% N Found: 56.7% C 3.0% H 8.4% N Example 27 4-Mesyl-6-(2'-chlornA ,-rnfluonomethylphenoxylcmnolThe.

The title compound (m.p. 153"C) was prepared either a) by oxidising the title compound of Example 20, employing potassium permanganate in aqueous acetic acid, or b) by treatment of the title compound of Example 18 with sodium mesylate in benzene under reflux.

Analysis Calculated: 47.7% C 2.5% H 7.0% N Found: 47.7% C 2.9% H 7.8% N Example 28 4- Tosyl-6-(2'-chloro-4 '-trifluoromethylphenoxyJcinnoline The title compound (m.p. 178"C) was prepared by analogous procedures to Example 27.

Analysis Calculated: 55.2% C 2.9% H 5.8% N Found: 54.5% C 2.9% H 6.1% N Example 29 4-[(1-Ethoxycarbonyl)ethoxy]-6-f2'-chloro-4'-trifluoromethylphenoxyocinnoline The title compound was prepared by treatment of the title compound of Example 18 with sodium (1-ethoxycarbonyl)ethoxide in tetrahydrofuran, under reflux, yielding on purification an oil.

Analysis Calculated: 54.5% C 3.7% H 6.3% N Found: 53.4%C 3.9% H 6.2% N Example 30 2-N-oxide of the title compound of Example 29 A procedure similar to that described in Example 2 followed by purification yielded the title compound, m.p. 1200C.

Analysis Calculated: 52.6% C 3.5% H 6.1% N Found: 52.9% C 3.6% H 6.0% N Example 31 4-Methyl-6-(2'-chloro-4'-trifluoromethylphenoxy)-1,2,3-benzotriazine, 3-N-oxide 4-(2'-Chloro-4'-trifluoromethylphenoxy)aniline-2-acetoxime (3.8g), prepared by the procedure of Example 6(a), was dissolved in acetic acid (lOmI). Molar hydrochloric acid was added (30ml). A solution of sodium nitrite (0.89) in water (3ml), was added dropwise over 15 minutes at 0 C.

The reaction mixture was allowed to reach room temperature then extracted with chloroform (2x25ml). The organic extracts were combined, washed and dried, the solvent was removed by evaporation, and the residue was recrystallised to yield the title compound as pale yellow crystals (2.8g), m.p. 164 C (decomposed).

Analysis Calculated: 50.6% C 2.5% H 11.8% N Found: 50.7% C 2.6% H 11.9% N Example 32 4-Methoxy-6-(2'-chloro-4'-trifluoromethylphenoxy)- 1, 2,3-benzotriazine.

(a) 4-(2'-chloro-4'-trifluoromethylphenoxy)aniline-2-carboxamide (18.89) was dissolved in the minimum amount of glacial acetic acid, and concentrated hydrochloric acid (20ml) and water (50ml) were added. The mixture was cooled to OOC. A solution of sodium nitrite (4.39) in water (10ml) was added dropwise over 30 minutes. After complete addition, 10 molar sodium hydroxide (25ml) was added to the reaction mixture.The reaction mixture was stirred for 10 minutes, acidified with concentrated hydrochloric acid until the pH was 2, then extracted with chloroform (2x 100ml). The extracts were washed and dried, the solvent was removed by evaporation, and the residue was purified by chromatography and recrystallisation to yield the compound of formula XXIX below in which Q is an oxygen atom, as pale yellow crystals (9.49), m.p. 178"C.

(b) The product of Example 32(a) (3.09) was dissolved in xylene (100ml) and phosphorus pentasulphide (4.09) was added. The reaction mixture was heated at llO"C under a nitrogen atmosphere for 1 hour. Water (500ml) at ambient temperature was added to the reaction mixture, which was then extracted with chloroform (2x200ml). The combined extracts were filtered and washed, dried, the solvents removed by evaporation and the residue purified by chromatography and recrystallisation to yield the compound of formula XXIX above, in which 0 represents sulphur, as yellow crystals (0.79), m.p. 213"C.

(c) A solution of sodium (0.19) in methanol was added to the product of Example 32(b) (1.2g). Methyl iodide (0.5g) was added to the resulting solution and the reaction mixture was refluxed for 20 minutes. The reaction mixture was poured onto water-diethyl ether (1:1, v:v, 50ml), and the organic layer was separated, washed and dried and the solvent evaporated. The yellow oil residue was purified by chromatography and recrystallisation to produce the title compound as colourless crystals (0.15g), m.p. 141-2"C.

Analysis Calculated: 50.6% C 2.5% H 11.8% N Found: 50.8% C 2.5% H 11.8% N Example 33 4-Merhoxy-6-(2 '-chloro4 '-trifluorome rh ylphenoxyl- 1.2, 3benzotriazine, 2-N-oxide The title compound was prepared as colourless crystals, (m.p. 129-130"C), by applying the procedure of Example 2 (but stirring the reaction mixture for 24 hours) to the product of Example 32.

Analysis Calculated: 48.4% C 2.4% H 11.3% N Found: 48.5% C 2.8% H 11.2% N Example 34 3-Amino-6-(2'-chloro-4'-trifluoromethylphenoxy)- 1,2, 4-benzotriazine, 1-N-oxide A solution of 4-(2'-chloro-4'-trifluoromethylphenoxy)-2-amino nitrobenzene (5.09) in glacial acetic acid (20 ml) was heated to boiling. To this solution were added concurrently concentrated hydrochloric acid (15ml), dropwise, and cyanamide (5.09), portionwise, over 10 minutes. After complete addition the reaction mixture was refluxed for 15 minutes, cooled to 50"C and made alkaline with 30% aqueous sodium hydroxide. The alkaline solution was refluxed for 10 minutes and allowed to cool. The cooled solution was extracted with chloroform, the extracts were dried and the solvent removed by evaporation.The residue was purified by chromatography to produce the title compound as yellow solid (0.5g), m.p. 217-8"C.

Analysis Calculated: 47.1% C 2.2% H 15.7% N Found: 47.0% C 2.7% H 15.2% N Chromatography carried out in the above Examples generally employed silica carrier metal, or occasionally alumina, and, as eluant, chloroform, chloroform/40-60 petroleum ether, chloroform/ethyl acetate or ethyl acetate/40-60 petroleum ether. Recrystallization was effected using hexane, ethyl acetate/hexane or ethanol/hexane.

Example 35 Herbicidal Activity To evaluate their herbicidal activity, compounds according to the invention were tested using as representative range of plants: maize, Zea mays (Mz); rice, Oryza sativa (R); barnyard grass, Linum usitatissium (L); mustard, Sinapsis alba (M); sugar beet, Beta vulgaris (SB) and soya bean, Glycine max (S).

The tests fall into two categories, pre-emergence and post-emergence. The pre-emergence tests involved spraying a liquid formuation of the compound onto the soil in which the seeds of the plant species mentioned above had recently been sown. The post-emergence tests involved two types of test, viz., soil drench and foliar spray tests. In the soil drench tests the soil in which the seeding plants of the above species were growing was drenched with a liquid formulation containing a compound of the invention, and in the foliar spray tests the seedling plants were sprayed with such a formulation.

The soil used in the tests was a prepared horticultural loam.

The formulations used in the tests were prepared from solutions of the test compounds in acetone containing 0.4% by weight of an alkylphenol/ethylene oxide condensate available under the trade mark TRITON X-155. These acetone solutions were diluted with water and the resulting formulations applied at dosage levels corresponding to 5 kg or 1 kg of active material per hectare in a volume equivalent to 600 litres per hectare in the soil spray and foliar spray test, and at a dosage of level equivalent to 10 kilograms of active material per hectare in a volume equivalent to approximately 3,000 litres per hectare in the soil drench tests.

In the pre-emergence tests untreated sown soil and in the post-emergence tests untreated soil bearing seedling plants were used as controls.

The herbicidal effects of the test compounds were assessed visually twelve days after spraying the foliage and the soil, and thirteen days after drenching the soil and were recorded on a 0-9 scale. A rating 0 indicates growth as untreated control, a rating 9 indicates death. An increase of 1 unit on the linear scale approximates to a 10% increase in the level of effect. The symbol '-' indicates that testing was not effected.

The results of the tests are set out in Tables I, II and Ill below, respectively denoting the foliar spray, pre-emergence and soil drench tests in which the compounds are identified by reference to the preceding examples.

Table I

Compound of Dosage Foliar Spray Example No. kg/ha Mz R BG O L M SB S 1 5 2 0 3 2035 3 1 1 0 0 1 0 2 3 2 2 5 3 0 3 0445 3 1 3 0 1 0 3 3 4 2 3 5 4 37 4636 7 1 2 0 2 0403 4 4 5 2 0 4 2443 3 1 2 0 2 1 3 3 2 3 5 5 6 28 7 9 7 - 7 1 4 1 5 5 8 7 - 6 6 5 5 3 8 5 7 6 7 7 1 3 2 7 4 6 6 6 7 7 5 7 4 9 8 9 9 9 7 1 4 27 9877 7 8 5 5 3 7 6 7 6 7 7 1 3 2 6 4 6 5 6 7 9 5 6 39 6968 6 1 5 28 3857 5 10 5 7 3 8 3 6 6 6 6 1 5 1 5 1 4 4 4 6 11 5 7 4 9 8 9 9 9 9 1 5 2 8 6 8 8 9 8 12 5 7 2 8 7 8 6 8 7 1 3 26 6835 5 13 5 5 3 4 2 3 3 5 4 1 4 2 2 1 2 2 3 2 14 5 3 0 4 3 4 4 6 3 1 2 0 1 2 2 2 4 2 15 5 4 3 8 4 7 6 6 3 1 2 1 5 3645 3 Table I continued..

@@@und of Dosage Foliar Spray @@@le No. kg/ha Mz R BG O L M SB S 16 5 0 0 4 3 3 4 2 0 1 0 0 0 0 1 1 0 0 18 5 4 2 7 4 7 8 8 7 1 2 25 2787 5 19 5 3 2 3 1 0 0 4 4 1 2 13 0004 4 20 5 4 3 8 6 7 6 8 7 1 4 26 5557 7 21 5 5 4 6 5 9 8 8 8 1 3 24 4856 6 22 5 6 3 6 4 7 5 6 5 1 6 24 2555 5 23 5 4 0 4 3 6 5 6 5 1 2 0 2 1 4 3 4 5 24 5 5 2 5 2 8 6 7 5 1 3 23 0766 3 25 5 5 4 7 5 9 9 9 6 1 3 25 3978 5 26 5 5 3 8 5 9 8 9 9 1 4 36 3979 8 27 5 1 0 1 0 5 4 5 3 1 1 0 0 0 2 2 - 2 28 5 4 0 3 2 6 5 6 4 1 2 0 2 1 4 5 4 2 29 5 7 5 6 5 9 7 7 8 1 6 23 3965 7 30 5 6 3 4 3 8 8 7 7 1 4 12 3876 6 Table I continued..

Compound of Dosage Foliar Spray ample No. kg/ha Mz R BG O L M SB S 31 5 6 5 9 8 9 9 9 8 1 4 48 5988 8 32 5 4 3 8 6 9 9 9 9 1 ~ ~ ~ - - - - - 33 5 4 3 9 5 9 9 9 9 1 4 3 8 5 9 9 9 9 34 5 4 3 6 4 8 5 6 8 1 - - - - - - - Table II

ound of Dosage Pre-emergence seeds ple No. kg/ha Mz R BG O L M SB S 4 5 0 0 0 1 4 6 8 0 1 0 0 0 0 0 6 7 0 5 5 0 0 2 2568 0 1 0 0 0 0222 0 7 5 3 0 8 6688 0 1 1 0 3 0055 0 8 5 0 0 6 3 6 5 5 1 1 0 0 4 1 4 3 3 1 9 5 0 16 0758 0 1 0 13 0412 0 10 5 0 - 0 8 0 6 5 8 2 1 0 0 3 0333 1 11 5 2 3 8 7 7 8 9 4 1 0 0 6 3438 0 12 5 0 0 3 0 0 3 7 0 1 0 0 2 0023 0 15 5 0 0 3 0 1 3 2 0 1 0 0 1 0 0 1 1 0 18 5 0 0 0 0 8 5 8 0 1 0 0 0 0516 0 21 5 2 1 5 2 9 8 9 4 1 1 0 0 1 7 6 7 2 22 5 2 0 0 0 6 5 7 0 1 2 0 0 0006 0 23 5 2 0 0 0 6 5 7 0 1 0 0 0 0300 0 24 5 0 0 7 3 8 8 9 3 1 0 0 4 1 7 7 8 1 Table II continued

und of Dosage Pre-emergence seeds Example No. kg/ha Mz R BG 0 L M SB S 25 5 0 0 7 5 9 9 9 5 1 0 0 4 1 8 8 8 0 26 5 0 0 2 0 6 6 7 0 1 0 0 1 0 3 3 5 0 29 5 1 1 5 3 8 9 4 0 1 0 0 1 1 2 7 3 0 30 5 1 0 3 0 5 8 6 0 1 1 0 1 0 0 6 4 0 31 5 5 6 8 7 8 8 8 0 1 0 45 4645 0 32 5 0 0 6 1 7 7 8 5 1 - - - - - - 33 5 0 0 7 2 6 8 9 5 1 0 0 5 1 6 6 8 0 34 5 0 0 0 0 5 3 7 0 1 - - - - - - - Table III

ound of Post-emergence soil drench (10kg/ha) ple No. Mz R BG O L M SB S 5 0 0 6 2 0 2 7 0 7 4 5 8 7- 6 3 4 3 8 5 36 4000 0 10 4 3 7 0 0 0 0 0 11 2 0 2 3 2 2 7 2 13 | 3 3 4 0 0 2 0 0 21 0 0 0 0 7 0 7 0 24 0 0 0 0 3 0 6 4 25 2 1 3 2 8 7 7 4 26 0 0 0 0 2 0 4 1 29 0 0 0 0 0 0 4 2 30 7 3 3 0 4 3 5 4 31 8 7 8 8 7 8 8 6 32 3 4 8 6 7 3 7 1 33 6 4 8 6 5 4 7 1

Claims

1. A benzoazine phenyl ether compound of the general formula 1, or an N-oxide, salt or inner salt thereof,

in which B represents a hydrogen or halogen atom, A' represents a hydrogen or halogen atom or an alkyl or haloalkyl group, and each of A2 and A3 independently represents a hydrogen or halogen atom or an alkyl, haloalkyl, nitro or cyano group, provided that B must represent a halogen atom when A1, A2 and A3 all represent hydrogen atoms; and X represents a group of formula CR', Y represents a group of formula CR2 and Z represents a group of formula CR3, in which each of R' and R2 independently represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group, or a cyano group, or a group of formula COR4, C02R4 or C02R4 where R4 represents an optionally substituted alkyl, alkenyl, cycloalkyl, aryl or aralkyl group, and R3 represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group; or X represents a group of formula CR5, Y represents a nitrogen atom and Z represents a group of formula CR6, in which each of R5 and R6 independently represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group, or R5 represents a hydrogen atom or an optionally substituted alkyl group and R6 represents a halogen atom or a cyano group or an optionally substituted alkoxy, alkylthio, alkylcarbonyl, alkoxycarbonyl or amino group; or X represents a group of formula CR7, Y represents a group of formula CR9 and Z represents a nitrogen atom, in which one of R7 and R8 represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group and the other represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group, or a halogen atom or a cyano group, or an optionally substituted alkoxy, alkylthio, alkylcarbonyl, alkoxycarbonyl or amino group, or R7 represents an amino group and R9 represents a cyano group or an optionally substituted alkoxycarbonyl group; or X represents a nitrogen atom, Y represents a group of formula CH and Z represents a group of formula CR9, in which R9 represents a hydrogen or halogen atom or an optionally substituted alkyl, alkenyl, cycloalkyl, aryl or aralkyl group, or a hydroxy or cyano group, or an optionally substituted amino, alkoxy, alkylthio, alkylsulphonyl, arylsulphonyl, alkylcarbonyl or alkoxycarbonyl group; or X and Y both represent nitrogen atoms and Z represents a group of formula CR'O in which R'O represents a hydrogen or halogen atom or a cyano group, or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group, alkoxy, alkylthio, amino, alkylcarbonyl, alkoycarbonyl or alkylphonyl group: or X and Z both represent nitrogen atoms and Y represents a group of formula CR" in which R" represents an optionally substituted amino group.

2. A compound according to claim 1 or an N-oxide, salt or inner salt thereof in which X represents a group of formula CR', Y represents a group of formula CR2 and Z represents a group of formula CR2 and Z represents a group of formula CR3, wherein R' and R2 each independently represents an optionally substituted alkyl or alkoxycarbonyl group and R3 represents an optionally substituted alkyl group; or X represents a group of formula CR5, Y represents a nitrogen atom and Z represents a group of formula CR6 wherein R5 represents a hydrogen atom or an optionally substituted alkyl group and R6 represents a hydrogen atom or an optionally substituted alkyl group, or an alkoxy group; or X represents a group of formula CR7, Y represents a group of formula CR8 and Z represents a nitrogen atom wherein each of R7 and Re independently represents a hydrogen atom or an optionally substituted alkyl or aryl group; or X represents a nitrogen atom, Y represents a group of formula CH and Z represents a group of formula CR9 wherein R9 represents a hydrogen or halogen atom or an alkyl, hydroxy or cyano group, or an amino group which is optionally substituted by one or two moieties selected independently from hydrogen atoms, alkyl groups, amino groups and groups of formula -N=CR'2R'3 where each of R12 and R'3 independently represents a hydrogen atom or an alkyl group, or R9 represents an alkylsulphonyl, optionally substituted phenylsulphonyl, alkylthio, or optionally substituted alkoxy group; or each of X and Y represents nitrogen atoms and Z represents a group of formula CR'O wherein R'O represents an optionally substituted alkyl or alkoxy group; or each of X and Z represents nitrogen atoms and Y represents an amino group.

3. A compound according to claim 2, or an N-oxide, salt or inner salt thereof, wherein X represents a group of formula CR5, Y represents a nitrogen atom and Z represents a group of formula CR6, wherein R5 represents a hydrogen atom or a C14 alkyl group and R6 represents a C14 alkyl or alkoxy group; or X represents a group of formula CR7, Y represents a group of formula CR6 and Z represents a nitrogen atom wherein each of R7 and R8 independently represents a hydrogen atom or a C14 alkyl group; or X represents a nitrogen atom, Y represents a group of formula CH and Z represents a group of formula CR9 wherein R9 represents a halogen atom, a C14 alkyl group, a C14 alkylthio group or a C14 alkoxy group which is optionally substituted by (C1-4 alkoxy) carbonyl group; or each of X and Y represents nitrogen atoms and Z represents a group of formula CR10 wherein R10 represents a C14 alkyl or C14 alkoxy group.

4. A compound according to claim 3, or an N-oxide thereof, wherein X represents a group of formula CH, Y represents a nitrogen atom and Z represents a group of formula CR6 where R6 represents a C14 alkyl group; or each of X and Y represents a group of formula CH and Z represents a nitrogen atom; or each of X and Y represents a nitrogen atom and Z represents a C14 alkyl or alkoxy group.

5. A compound according to any of claims 1 to 4 wherein A represents a trifluoromethyl group, A2 represents a halogen atom and A3 represents a hydrogen atom.

6. A compound of formula I, substantially as hereinbefore described with reference to the Examples.

7. A process for the preparation of a diphenyl ether as claimed in claim 1, which comprises reacting a compound of formula li with a compound of formula lil

where one of the moieties R'A and R2A represents an optionally substituted alkoxycarbonyl or aryloxycarbonyl group and the other represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, aryl, aralkyl, alkoxycarbonyl or aryloxycarbonyl group, and RA represents an alkyl, cycloalkyl or optionally substituted aryl group; or reacting a compound of formula IV with a compound of formula V

or reacting a compound of formula VI with ammonia

where each of R5A and R6A independently represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group; or reacting a compound of formula VII with a compound of formula VIII

where each moiety R14 represents an alkyl group, R5 represents a hydrogen atom or an optionally substituted alkyl group, and R66 represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group, or a cyano group, or an optionally substituted alkoxy, alkoxy, alkylthio, alkoxycarbonyl or amino group; or halogenating a compound of formula IX

where R5c represents a hydrogen atom or an optionally substituted alkyl group, to produce a compound of formula I in which R6 is a halogen atom, and optionally converting the halogen substituent R8 of the resulting compound of formula I into a cyano group or an optionally substituted alkoxy, alkylthio, alkylcarbonyl, alkoxycarbonyl or amino group; or reacting a compound of formula X with a compound of formula XI, or with a polymeric derivative thereof,

where each of R7A and R8A independently represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group; or halogenating a compound of the general formula XII or Xl!l

in which the moiety R7B ir R88 represents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group, and optionally converting the halogen substituent R8 or R7 of the resulting compound of formula I into a cyano group or an optionally substituted alkoxy, alkylthio, alkylcarbonyl, alkoxycarbonyl or amino group; or reacting a compound of formula XIV with a compound of formula XV

where each of R7C and R8C independently represents a hydrogen atom or an optionally substituted alkyl, alkenyl cycloalkyl, aryl or aralkyl group; or reacting a compound of formula XIV with malononitrile to form a compound of formula I in which R7 is an amino group and R9 is a cyano group, and optionally converting the cyano group into an optionally substituted alkoxycarbonyl group; or diazotising a compound of the formula XVI

where R9A represent a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl, aryl or aralkyl group; or diazotising a compound of formula XVII

in which RAO reprcsents a hydrogen atom or an optionally substituted alkyl, cycloalkyl, alkenyl aryl or aralkyl group, a cyano group, or an optionally substituted alkoxy, alkylthio, alkylcarbonyl, alkoxycarbonyl or amino group; or by S-alkylation of a compound of formula XIX

to produce a compound of formula I in which R'O is an optionally substituted alkylthio group, and optionally converting that compound to a compound of formula I in which R10 is a halogen atom or a cyano group or an optionally substituted alkoxy, amino, alkylcarbonyl, alkoxycarbonyl group or alkylsulphonyi group; or reacting a compound of formula XX with optionally substituted cyanamide

to produce a compound of formula I in which R11 represents an optionally substituted amino group; wherein, in any of the above steps, Q represents a halogen atom or a nitro group or a group of formula -OM, where M represents a hydrogen or alkali metal atom or a group of formula

and, when any of the above steps yields a compound in which Q does not represent a group of formula

reacting said compound with a compound of formula XXI

in which compound W represents a halogen atom or a nitro group when Q represents a group -0M1 where M1 represents a halogen or alkali metal atom, and W represents such a group -OM1 when 0 represents a halogen atom or a nitro group, and optionally converting any product to an N-oxide or reducing any N-oxide formed, and optionally converting any product to a salt or inner salt.

8. A process substantially as hereinbefore described with reference to the Examples.

9. A herbicidal composition comprising a compound of formula I as defined in any one of claims 1 to 6, with at least one carrier.

10. A herbicidal composition according to claim 9, comprising at least two carriers, at least one of which is a surface active agent.

11. The use of a compound according to claim 1 to 6 or of a composition according to claim 9 or 10, as a herbicide.

12. A method of combating undesired plant growth at a locus by treating the locus with a compound of formula I as defined in any of claims 1 to 6 or a composition according to claim 9 or 10.