GB1574429A

GB1574429A - Thienylquinoxaline compounds and their use in herbicidal compositions

Info

Publication number: GB1574429A
Application number: GB1727376A
Authority: GB
Original assignee: SHELL INT RESEARCH; Shell Internationale Research Maatschappij BV
Current assignee: SHELL INT RESEARCH; Shell Internationale Research Maatschappij BV
Priority date: 1977-04-26
Filing date: 1977-04-26
Publication date: 1980-09-10

Description

(54) THIENYLQUINOXALINE COMPOUNDS AND THEIR USE IN HERBICIDAL COMPOSITIONS (71) We, SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ B.Al., a company organised under the laws of The Netherlands, of 30 Carel van Bylandtlaan, The Hague, The Netherlands, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to herbicidally active compositions comprising as active ingredient certain thienylquinoxaline compounds. The invention also relates to novel thienylquinoxaline compounds, to processes for their preparation and to a method of eradicating or controlling weeds.

The invention provides a herbicidal composition which comprises a surface-active agent and/or a solid or liquid carrier and as active ingredient a thienylquinoxaline compound of general formula:

wherein either i) ;( represents a nitrogen atom and R represents a hydrogen or a halogen atom. an alkoxy group, an optionally substitut--4 aryloxy group or an optionally substituted amino group; or ii) , represents an -UN- group and R represents an oxygen atom; or an N-oxide or a salt of said compound.

Preferred herbicidal compositions according to the invention are those in which the active ingredient iz a compound of formula I wherein either (i) X represents a nitrogen atom and R represents a hydrogen or halogen atom, an alkoxy group of 1 to 4 carbon atoms, an optionallv substituted aryloxy group of up to 10 carbon atoms, or a group of formula -NR'R m which R1 represents a hydrogen atom or an alkyl group of up to 6 carbon atoms and R2 represents a hydrogen atom. an alkyl group of up to 6 carbon atoms, an amino group or an aralkyl group of up to 10 carbon atoms or Rl and R2 together with the nitrogen atom represent a heterocyclic ring containing one or two hetero-atoms; or ii) X represents an -NH- group and R represents an oxygen atom; or an N-oxide or a salt of said compound.

Particularly preferred herbicidal compositions according to the invention are those in which the active ingredient is a compound of formula I wherein X represents a nitrogen atom and R represents a hydrogen or chlorine atom, an alkoxy group of 1 to 4 carbon atoms, for example a methoxy group, a halogen-substituted aryloxy group, for example a 2.4-dichlorophenoxy group. a substituted amino group, for example a hydrazino or benzy:amino group or a 6-membered nitrogen-containing heterocyclic ring for example a piperidino ring: or an N-oxide or a salt of said compound.

Salts of the compounds of the general formula I should be understood to include compounds in which a nitrogen atom carries a substituent, preferably N-alkyl salts with an anion, such as iodide or p-toluenemethosulphate.

An especially preferred herbicidal composition is one in which the active ingredient is a quinoxa me compound of formula I wherein R represents a hydrogen or chlorine atom or a methoxy group.

The novel compounds of the invention are those having the above general formula I together with the N-oxide and salts thereof with the exception of the compound 2-(2-thienyl)quinoxaline.

The novel compound according to formula I wherein X represents an -NH- group and R an oxygen atom may be prepared by a process which comprises reacting ortho-phenylene diamine with a keto-acid of formula:

The reaction may be carried out by heating the two reactants, preferably in an inert solvent, for example an alcohol such as ethanol, or an ether such as dioxan.

A novel compound of formula I wherein X represents a nitrogen atom and R represents a halogen atom may be prepared by reacting the compound according to formula I wherein X represents an -NH- group and R represents an oxygen atom with a halogenating agent, preferably a phosphoryl halide, for example the chloride.

The novel compounds of formula I in which X represents a nitrogen atom and R represents an alkoxy, optionally substituted aryloxy, or optionally substituted amino group, may be prepared by reacting a compound according to formula I in which X represents a nitrogen atom and R represents a halogen atom, with an alkali metal alkoxide or aryloxide, or the amine of formula RH.

N-oxides of the compounds according to formula I may be prepared by reacting the compounds with an oxidizing agent for example a peracid such as perbenzoic acid.

N-alkyl salts of the compounds according to the invention may be prepared by reacting a compound of formula I wherein R represents a hydrogen or halogen atom, preferably a chlorine atom, with a suitable quaternizing agent for example an alkylarylsulphonate such as methyl p-toluenesulphonate. The reaction takes place in the absence of solvent and the reaction melt may be worked up by conventional means.

The compositions according to the invention exhibit good herbicidal activity, in particular when applied as a foliar spray. The invention therefore also provides a method of eradicating or controlling weeds at a locus which comprises applying to that locus a herbicidally effective amount of a composition according to the invention or a novel compound as specified above.

The term "carrier" as used herein means a material, which may be inorganic or organic and of synthetic or natural origin, with which the active compound is mixed or formulated to facilitate its application to the plant, seed, soil or other object to be treated, or its storage, transport or handling. The carrier may be a solid or a liquid. Any of the materials usually applied in formulating pesticides, herbicides, or fungicides may be used as carrier.

Suitable solid carriers are natural and synthetic clays and silicates for example natural silicas such as diatomacious earths; magnesium silicates, for example, talcs; magnesium aluminium silicates, for example, attapulgites and vermiculites; aluminium silicates, for example, kaolinites, montmorillonites and micas; calcium carbonates; calcium 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 polychlorophenols; bitumen; waxes, for example, beeswax, paraffin wax, and chlorinated mineral waxes; and solid fertilisers, for example, superphosphates.

Suitable liquid carriers are water, alcohols, for example, isopropanol and glycols; ketones, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethers, aromatic 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; and liquefied, normally vaporous, gaseous compounds. Mixtures of different liquids are often suitable.

The surface-active agent may be an emulsifying agent or a dispersing agent or a wetting agent; it may be nonionic or ionic. Any of the surface-active agent usually applied in formulating pesticides, herbicides or fungicides may be used. Examples of suitable surface-active agents are the sodium or calcium salts of polyacrylic acids and lignin sulphonic acids; the condensation products 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 cr pentaerythritol; condensates of these with ethylene oxide and/or propylene oxide; condensation products of fatty alcohols or alkyl phenols for example p-octylphenol or p-octylcresol, with ethylene oxide and/or propylene oxide; sulphates or sulphonates of these condensation products; alkali or alkaline earth metal salts, preferably sodium salts, or 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 alkylaryl sulphonates such as sodium dodecylbenzene sulphonate; and polymers of ethylene oxide and copolymers of ethylene oxide and propylene oxide.

The compositions according to the invention may be formulated as wettable powders, dusts, granules, solutions, emulsifiable concentrates, emulsions, suspension concentrates and aerosols. Wettable powders are usually compounded to contain 25, 50 and 75% w of toxicant and usually contain, in addition, to solid carrier, 3-10% w of a dispersing agent and, where necessary, 0-10% w of stabilizer(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 0.5-10% w of toxicant. 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 0.5 - 25% w of additives such as stabilisers, slow release modifiers and binding agents. Emulsifiable concentrates usually contain, in addition to the solvent and, when necessary, co-solvent, 10-50% w toxicant, 2-20% w/v emulsifiers and 0-20% w/v of appropriate additives such as stabilisers, penetrants and corrosion inhibitors. Suspension concentrates are compounded so as to obtain a stable, non-sedimenting flowable product and usually contain 10-75% w toxicant, 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 appropriate additives such as defoamers, corrosion inhibitors, stabilisers, penetrants and stickers. and as carrier, water or an organic liquid in which the toxicant is substantially insoluble; certain organic solids or inorganic salts may be dissolved in the carrier to assist in preventing sedimentation or as antifreeze 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 present 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 compositions of the invention may also contain other ingredients, for example, other compounds possessing pesticidal. herbicidal or fungicidal properties.

The invention is further illustrated in the following examples: EXAMPLE 1 Preparation of '-('2-tllienvlJqunoxaline 2-Acetylthiophene (9.6g) was refluxed for 4 hours with selenium dioxide (8.4g) in dioxan (45 ml) and ether ('.0 ml). The precipitated selenium was filtered off and the filtrate, containing 2-thienylglyoxal. added to o-phenylenediamine (8.lg) and refluxed for 30 minutes. The reaction mixture was poured into water and the precipitated solid removed and recrvstailised from methanol to give the desired product as a white crystalline solid m.p 116-118 C. Yield=63%.

Analysis Calculated for Cl2H8SN2 C 67.9; H 3.8; N 13.2% Found C 67.9: H 3.9; N 13.1% EXAMPLE 2 Preparation of 3- (2-titienyl) quinoxallne-1 -oxide A mixture of '-(2-thienyl)quinoxaline (1.05g) and m-chloroperbenzoic acid (1.0g) in chloroform (10.0 ml) was left at room temperature in the dark for 72 hours. After removal of solvent, the residue was washed with sodium bicarbonate solution and crystallised from ethanol to give the desired product as a pale yellow solid m.p. 168-169"C. Yield=64%.

Analysis Calculated for C12HN2SO C 63.2; H 3.5; N 12.2% Found C 63.0; H 3.5; N 11.8% EXAMPLE 3 Preparation of ?-chloro-3- ('-tllenyl)quinoxaline 1H-2-oxo-3-(?-thienyl)quinoxaline (0.5g) (prepared by treating 2-thienylglyoxalic acid with o-phenylenediamine) was refluxed for 6 hours with phosphorylchloride (10 ml). The reaction mixture was cooled and poured onto ice. The solid, collected by filtration, was crystallised from ethanol to give the desired product as a pale yellow solid m.p. 111-112 C.

Yield=80%.

Analysis Calculated for Cs2H7N2S Cl : C 58.4; H 2.8; N 11.4% Found : C 58.2; H 2.8; N 11.0% EXAMPLE 4 Preparation of 2-methoxy-3-(2-thienyl)quinoxaline 2-chloro-3-(2-thienyl)quinoxaline (0.5g) was refluxed for 2 hours with sodium (0.1g) in methanol (10 ml). The reaction mixture was filtered, the filtrate evaporated and the residue treated with 2N sodium hydroxide. The precipitated solid was collected and crystallised from aqueous methanol to give a pale yellow solid m.p. 75 C. Yield=70%.

Analysis Calculated for C13H10N2SO : C 64.5; H 4.1; N 11.6% Found : C 64.3; H 4.0; N 11.4% EXAMPLE 5 Preparation of l-methyl-3-(2-thienyl)quinoxaline p-toluenemethosulphonate 2- (2-thienyl quinoxaline (1.0g) was heated with methyl p-toluenesulphonate (1.0g) to 140"C. The melt which formed was allowed to cool and poured into water. After filtration the filtrate was extracted with ether and the aqueous extract evaporated to dryness and triturated with acetone to give the desired product as a pale yellow solid m.p. 204-206 C.

Yield=75%.

Analysis Calculated for C20H18N2S203 : C 60.3; H 4.5; N 7.0% Found : C 60.5; H 4.6; N 6.9% EXAMPLES 6-11 Following procedures similar to those given in the Examples 1-5 further compounds were prepared and are described in Table I.

TABLE I Example No. Compound m.p. C Analysis 6 1-methyl-3-(2-thienyl) 227 C Calculated for C13H11N2SI : C 44.1; H 3.1; H 7.9% quinoxalinium iodide Found : C 44.2; H 3.2; N 7.7% 7 1-H-2-oxo-3-(2-thienyl) 268-270 C Calculated for C12H8N2SO : C 63.2; H 3.5; N 12.3% quinoxaline Found : C 63.6; H 3.6; N 12.0% 8 2-hydrazino-3-(2-thienyl) 152 C Calculated for C12H10N4S : C 59.5 H 4.1; N 23.1% quinoxaline Found : C 59.4; H 4.3; N 22.7% 9 2-piperidino-3-(2-thienyl) 86 C Calculated for C17H17N3S : C 69.1; H 5.8; N 14.2% quinoxaline Found : C 69.1; H 5.9; N 14.0% 10 2-(2,4-dichlorophenoxy) 172 C Calculated for C18H10N2SO Cl2 : C 57.9; H 2.7; N 7.5% -3-(2-thienyl) quinoxaline Found : C 57.5; H 2.5; H 7.3% 11 2-benzylamino-3- 87 C Calculated for C19H15N3S : C 71.6; H 4.8; N 12.9% (2-thienyl)quinoxaline Found : C 71.6; H 4.8; N 12.9% EXAMPLE 12 Demonstration of herbicidal activity To further evaluate their herbicidal activity the compounds according to the invention were tested using as a representative range of plants: Maize, Zea mays (MZ); rice, Oryza sativa (R); barnyard grass, Echinchloa crusgalli (BG); oat, Avena sativa (0); linseed Linum usitatissimum (L); mustard, Sinapsis alba (M); sugar beet, Beta vulgaris (SB); and soya bean, Glycine max (S).

The tests carried out were post-emergence tests and involved foliar spray of seedling plants with a liquid formulation containing a compound of the invention. The formulations used in the test were prepared by diluting with water solutions of the compounds in acetone containing 0.4% by weight of an alkylphenol/ethylene oxide condensate available under the Registered Trade Mark Triton X-155. The acetone solutions were diluted with an equal volume of water and the resulting formulations applied at two dosage levels corresponding to 5 and 1 kilograms of active material per hectare respectively in a volume equivalent to 400 litres per hectare. The herbicidal effects of the compounds were assessed visually seven days after spraying the foliage and were recorded on a 0-9 scale. A rating 0 indicates no effect on the treated plants, a rating 2 indicates a reduction in fresh weight of stem and leaf of the plants of approximately 25%, a rating 5 indicates a reduction of approximately 55%, a rating 9 indicates a reduction of 95%.

The results of the test are set out in Table II.

TABLE II Example No. Compound Dosage kg/ha Post-Emergence (Foliar Spray) MZ R BG O L M SB S 1 2-(2-thienyl)quinoxaline 5 5 4 9 9 9 9 9 9 1 3 3 8 8 9 9 9 9 2 3-(2-thienyl)quinoxaline-N-oxide 5 3 2 6 7 8 9 8 8 1 1 0 2 1 7 7 8 6 3 2-chloro-3-(2-thienyl)quinoxaline 5 4 4 9 7 9 9 9 9 1 3 4 7 7 9 9 9 9 4 2-methoxy-3(2-thienyl)quinoxaline 5 9 7 9 9 9 9 9 8 1 5 5 9 7 9 9 9 6 5 1-methyl-3-(2-thienyl)quinoxaline 5 4 7 9 8 9 9 9 9 p-toluenemethosulphonate 1 2 5 7 6 6 8 9 8 6 1-methyl-3-(2-thienyl) 5 7 3 9 9 9 9 9 8 quinoxalinium iodide 1 1 0 6 5 6 9 9 4 7 1-H-2-oxo-3-(2-thienyl) 5 2 1 5 5 8 8 6 5 quinoxaline 1 1 0 4 1 7 5 4 4 8 2-hydrazino-3-(2-thienyl) 5 2 5 9 6 9 9 7 5 quinoxaline 1 2 4 5 4 7 8 5 3 9 2-piperidino-3-(2-thienyl) 5 5 5 7 6 7 8 9 6 quinoxaline 1 2 3 6 3 5 6 7 5 11 2-benzylamino-3-(2-thienyl) 5 5 4 8 7 8 9 8 7 quinoxaline 1 2 2 7 4 6 8 6 5

Claims

WHAT WE CLAIM IS:

1. A herbicidal composition comprising a surface-active agent and/or a solid or liquid carrier and as active ingredient a thienylquinoxaline compound of general formula:

wherein either i) X represents a nitrogen atom and R represents a hydrogen or a halogen atom, an alkoxy group, an optionally substituted aryloxy group or an optionally substituted amino group; or ii) X represents an -NH- group and R represents an oxygen atom; or an N-oxide or a salt of said compound.

2. A composition according to claim 1, wherein the active ingredient is a compound of formula I wherein either i) X represents a nitrogen atom and R represents a hydrogen or halogen atom, an alkoxy group of 1 to 4 carbon atoms, an optionally substituted aryloxy group of up to 10 carbon atoms, or a group of formula -NR1R2 in which R1 represents a hydrogen atom or an alkyl group of up to 6 carbon atoms and R2 represents a hydrogen atom, an alkyl group of up to 6 carbon atoms, an amino group or an aralkyl group of up to 10 carbon atoms or R1 and R2 together with the nitrogen atom represent a heterocyclic ring containing one or two hetero-atoms; or ii) X represents an -NH- group and R represents an oxygen atom; or an N-oxide or a salt of said compound.

3. A composition according to claim 2, wherein the active ingredient is a compound of formula I wherein X represents a nitrogen atom and R represents a hydrogen or chlorine atom, an alkoxy group of 1 to 4 carbon atoms, a halogen-substituted aryloxy group, a substituted amino group; or a 6-membered nitrogen-containing helerocyclic ring; or an N-oxide or a salt of said compound.

4. A composition according to claim 3, in which the active ingredient is a compound of formula I in which R represents a methoxy, 2,4-dichlorophenoxy, hydrazino, benzylamino or piperidino group, or an N-oxide or a salt of said compound.

5. A composition according to any one of claims 1 to 4, in which the active ingredient is an N-alkyl salt of a compound of the general formula I.

6. A composition according to claim 1, wherein the active ingredient is a quinoxaline compound according to formula I wherein X represents a nitrogen atom and R represents a hydrogen or chlorine atom or a methoxy group.

7. A composition as claimed in claim 1, in which the active ingredient is any one of those named in Examples 1 to 11 herein.

8. A compound which is a thienylquinoxaline of the general formula I or an N-oxide or a salt thereof as defined in any one of claims 1 to 7, with the proviso that the compound is not 2-(2-thienyl)quinoxaline.

9. A process for the preparation of a compound as claimed in claim 8 which is a thienylquinoxaline of the general formula I in which X represents an NH group and R represents an oxygen atom, which comprises reacting o-phenylenediamine with the keto-acid of formula

10. A process for the preparation of a compound as claimed in claim 8 which is a thienylquinoxaline of the general formula I in which X represents a nitrogen atom and R represents a halogen atom, which comprises reacting a compound of the general formula I in which X represents an NH group and R represents an oxygen atom with a halogenating agent.

11. A process for the preparation of a compound as claimed in claim 8 which is a thienylquinoxaline of the general formula I in which X represents a nitrogen atom and R represents an alkoxy, optionally substituted aryloxy or optionally substituted amino group, which comprises reacting a compound of the general formula I in which X represents a nitrogen atom and R represents a halogen atom, with an alkali metal alkoxide or aryloxide, or the amine RH.

12. A compound as claimed in claim 8, whenever prepared by a process as claimed in any one of claims 9 to 11.

13. A method of eradicating or controlling weeds at a locus, which comprises applying to that locus a herbicidally effective amount of a composition as claimed in any one of claims 1 to 7 or a compound as claimed in either claim 8 or claim 12.