GB2213145A

GB2213145A - Herbicidal oximino ether compounds

Info

Publication number: GB2213145A
Application number: GB8827849A
Authority: GB
Inventors: Terence Gilkerson
Original assignee: Shell Internationale Research Maatschappij BV
Current assignee: Shell Internationale Research Maatschappij BV
Priority date: 1987-12-01
Filing date: 1988-11-29
Publication date: 1989-08-09
Also published as: GB8827849D0

Abstract

The invention relates to the compounds of the general formula I: <IMAGE> wherein R represents a hydrogen atom, or an optionally-substituted alkyl, acyl, alkenyl or alkynyl group or an inorganic or organic cation; R<1> or R<2> represents a hydrogen atom or a straight-chain alkyl group having 1 to 3 carbon atoms; the other of R<1> or R<2> represents a straight-chain alkyl group having 1 to 3 carbon atoms; and R<3> and R<4> each independently represents an optionally-substituted alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl or phenyl group, which are useful as herbicides. Certain intermediate compounds used to prepare the compounds of formula I are also claimed.

Description

OXIMINO ETHER COMPOUNDS This invention relates to novel oximino ether compounds, to their use as herbicides, to their preparation, and to certain intermediates therefor and their preparation.

In accordance with the present invention there are provided compounds of the general formula I:

wherein R represents a hydrogen atom, or an optionally-substituted alkyl, acyl, alkenyl or alkynyl group or an inorganic or organic cation; R1 or R2 represents a hydrogen atom or a straight-chain alkyl group having 1 to 3 carbon atoms; the other of R1 and R2 represents a straight-chain alkyl group having 1 to 3 carbon atoms; and R3 and R4 each independently represents an optionally-substituted alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl or phenyl group.

Unless otherwise specified herein, an alkyl group, including the alkyl linkage of an aralkyl group, suitably has 1 to 6, especially 1 to 4 carbon atoms; an alkenyl or alkynyl group suitably has 2 to 6, especially 2 to 4 carbon atoms. A cycloalkyl group preferably has 3 to 6 carbon atoms, and is preferably cyclopropyl.

Suitable optional substituents for an alkyl, alkenyl, alkynyl or cycloalkyl group may be selected from halogen atoms and C16 alkoxy, C1 6 alkylthio, (C1 -6 alkoxy) carbonyl and optionally-substituted phenyl groups. Suitable optional substituents for a phenyl group may be selected from halogen atoms and nitro, cyano, C16 alkyl, C16 haloalkyl, C16 alkoxy and C16 alkylthio groups.

An acyl group may be defined as a group formed by removal of -OH from an organic acid. Suitable acyl groups include C 2-6 alkanoyl and optionally-substituted benzoyl groups, and sulphonyl groups, for example alkylsulphonyl or arylsulphonyl groups. Suitable as cations are alkali and alkaline earth metal ions, transition metal ions and optionally-substituted ammonium ions, optional substituents being 1-4 groups independently selected from optionally-substituted alkyl, phenyl and phenalkyl groups.

When halogen is an optional substituent, the group is suitably substituted by 1 to 3 halogen atoms, preferably selected from fluorine and chlorine.

R in formula I is preferably a hydrogen atom.

R and R are preferably each independently a methyl, ethyl or n-propyl group.

R3 and R4 are preferably each independently an alkyl or alkenyl group. Preferably R3 is an alkyl group and R4 is an alkyl, alkenyl or haloalkenyl group.

It should be noted that when R is hydrogen the compounds of the invention may exist in one of the tautomeric forms as shown below:

In this specification, recitation of anyone of these forms denotes any tautomer or the tautomer mixture of which the recited form is a constituent.

In relation to precursors, the reaction of any one tautomer also denotes any tautomer or the tautomer mixture.

The compounds of the invention may be prepared by a variety of methods and in a further aspect the invention provides methods for the preparation of compounds of formula I.

The compounds of formula I where R is hydrogen may be prepared by reacting a compound of formula II:

where R1, R2, and R3 are as defined above, with hydroxylamine to give an intermediate oxime derivative of formula I above wherein R4 represents hydrogen, and reacting this oxime derivative with a compound of formula R4-L, wherein R4 is a group as defined above and L is a leaving group such as, for example, chloride, bromide, iodide, sulphate, nitrate, methyl sulphate, ethyl sulphate, tetrafluoroborate, hexafluorophosphate, hexafluoroantimonate, methanesulphonate, fluorosulphonate, fluoromethanesulphonate and trifluoromethanesulphonate, or, preferably, by reacting a compound of formula II directly with a derivative of formula N2N-O-R4, or an acid salt thereof, eg. a hydrochloride, in the presence of a base such as triethylamine.

Oxidation suitably takes place at a temperature in the range 0 to 50"C, conveniently at ambient temperature, optionally in the presence of water and/or an organic solvent, suitably an alcohol, for example methanol or ethanol, and optionally, when an acid salt is used, in the presence of a base, suitably an amine base such as triethylamine.

Compounds of formula I where R is hydrogen may be converted to compounds of formula I where R is other than hydrogen by reaction with a suitable compound X-L, where X is a group as defined above for R other than hydrogen and where L is a leaving group as exemplified above, or with an inorganic or organic base or salt, suitably at a temperature in the range 0-100eC, preferably 20-50eC, in the presence of an organic solvent and/or water.

The compounds of formula II may be prepared by acylation of a compound of formula III:

where R1 or R2 are as defined above. This may be effected by reacting the compound of formula III with an acid of formula R3 COOH (where R3 is as defined above) or a salt, anhydride or, preferably, an acid halide thereof in the presence of an amine base such as triethylamine and under conditions favouring rearrangement (such as the presence of an organic solvent such as acetonitrile and a Lewis acid such as magnesium chloride at a temperature in the range of 0 to 50"C. The reaction may be effected in the presence of a polar organic solvent such as pyridine or acetonitrile at an elevated temperature, for example 40"C to 1500C, in the presence of a Lewis acid, for example zinc chloride, zinc cyanide, aluminium chloride, 4-(N-dimethylamino)pyridine or a polymeric Lewis acid catalyst comprising at least one pyridylamino functional group.

Certain compounds of formula III are known for example from West German Patent Application No.

3230923 and can be prepared for example by condensation of a compound of formula IV with a compound of formula V

where R and R are groups as defined above and Hal represents a halogen atom, suitably chlorine, in a suitable solvent such as toluene at a temperature in the range of 0 to 1500C.

The invention also includes intermediates of formula II and their preparation as described above.

Compounds of formula I have been found to show interesting activity as herbicides, showing high activity against undesirable grasses, such as blackgrass, wild oats, annual meadow grass, Red Fescue and barnyard grass, whilst low or no activity against useful, non-target species, including linseed, mustard, sugar beet, rape and soya.

Accordingly, the invention further provides a herbicidal, especially graminicidal, 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, especially as a graminicide. 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. The locus may for example be a crop area in which the compound selectively combats weed growth. Application to the locus may be pre-emergence or post-emergence. The dosage of active ingredient used may, for example, be from 0.01 to 10 kg/ha, preferably 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.

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 sulphate; 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 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 calcium 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 p-octylphenol or -octylcresol, 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 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 i-10% 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 i-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 conentrates are usually compounded so as to obtain a stable, non-sedimenting flowable product and usually contain 10-75% w active ingredient, 0.5-15% w of dispersing agents, 0.1-10t 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 will now be further described with reference to the accompanying Examples. Examples 1 to 8 relate to the preparation of precursors and the remaining Examples relate to the preparation of compounds of formula I and illustrate their herbicidal activity. Structures of compounds were confirmed by mass spectrometry and nuclear magnetic resonance analysis.

Example 1 Preparation of 2,6-dimethyl-3,5-dioxo-2H-3,4,5,6 tetrahydro-1,2,6-thiadiazine-l,l-dioxide N-N'-dimethyl sulphamide (24.8g) and malonyl chloride (28.2g) in dry toluene (200 ml) were heated at 50 for half an hour and then at 70C overnight.

Evaporation of the toluene in vacuo and purification of the residue on a silica gel column using methylene chloride eluant gave the title compound (25.lg) as a solid of melting point 96-98"C.

Analysis: Calculated for C5H8N204S: C 31.3; H 4.2; N 14.6% Found C 31.8; H 4.2; N 14.5% Examples 2 and 3 By similar methods to that described in Example 1, the following further compounds of formula I were prepared: 2,6-diethyl-3,5-dioxo-2H-3,4,5,6-tetrahydro-1,2,6- thiadiazine-l,1-dioxide (m.p. 42-43 C) 2,6-dipropyl-3,5-dioxo-2H-3,4,5,6-tetrahydro-1,2,6- thiadiazine-l,l-dioxide (oil) Example 4 Preparation of 2,6-dimethyl-3-hydroxy-5-oxo-4 propionyl-l, 2,6- thiadiazine-l, l-dioxide Magnesium chloride (4.8g) was added to dry acetonitrile (50ml) under a nitrogen atmosphere.

2,6-dimethyl-3,5dioxo-2H-3,4,5,6-tetrahydro-1,2,6- thiadiazine-l,l-dioxide (9.6g) was then added and the mixture cooled to 0 C. Triethylamine (10.lg) was added, followed, after 15 minutes, by the dropwise addition of propionyl chloride (4.6g). After stirring at 00C for a further 1 hour, the reaction mixture was allowed to come to room temperature and then stirred overnight. 5N hydrochloric acid (50 ml) was subsequently added and the mixture extracted with diethyl ether. After drying the extracts over anhydrous magnesium sulphate, the ether was evaporated. Purification on a silica gel column using methylene chloride as eluent gave the title compound (7.lg) as a yellow oil.

Analysis: Calculated for C8H12N205S: C 38.7; H 4.8; N 11.3% Found C 38.2; H 4.9; N 11.1% Examples 5 to 8 The following further compounds of formula II, set out in Table I below were made in a similar manner to that described in Example 4 above.

Table 1

C H N Example R R R Cal % Fd % Cal % Fd % Cal % Fd % m.p.

5 Me Me npr 41.2 41.3 5.3 5.0 10.7 10.8 yellow oil 6 Et Et npr 45.5 46.2 6.2 6.3 9.7 9.7 yellow oil 7 Me Me Me 35.9 34.4 4.3 4.3 11.9 12.3 yellow oil 8 npr npr npr 49.0 49.1 6.9 6.9 8.8 8.2 yellow oil Example 9 Preparation of 2,6-dimethyl-3-hydroxy-5-oxo-4[-1 (allyloximino) propyl]-1,2,6-thiadiazine-1,1-dioxide Triethylamine (1.4g) was added to a stirred solution of 2, 6-dimethyl-3-hydroxy-5-oxo-4-propionyl- 1,2,6-thiadiazine-1,1- dioxide (3g) and O-allylhydroxylamine hydrochloride (1.55g) in ethanol (50 ml) at room temperature. After stirring overnight, the ethanol was evaporated in vacuo and methylene chloride added to the residue. After washing with water, brine and drying over anhydrous magnesium sulphate the methylene chloride was evaporated.

Purification of the residue on a silica gel column with methylene chloride as eluent gave the title compound (2.0g) as a white solid of m.p. 66-68C.

Analysis Calculated for C11H17N3O5S: C 43.6; H 5.6; N 13.9% Found C 42.7; H 5.7; N 13.5% Examples 10 to 15 The following further compounds of formula I, set out in Table 2 below were made in a similar manner to that described in Example 9 above.

Table 2

Example C H N No. R R R R4 Cal % Fd % Cal % Fd % Cal % Fd % mp C 10 Me Me Et Et 41.2 41.2 5.8 5.8 14.4 14.4 97-99 11 Me Me npr allyl 45.4 46.4 6.0 6.2 13.2 13.2 clear oil 12 Et Et npr allyl 48.7 48.2 6.7 6.6 12.2 12.5 63-65 13 npr npr npr allyl 51.5 51.0 7.2 7.2 11.2 11.2 30-32 14 Me Me Me allyl 41.5 38.9 5.2 4.8 14.5 14.1 56-58 15 Me me Me -CH2CH=CH-Cl 37.1 36.1 4.3 4.6 13.0 13.2 clear oil (trans) Example 16 Herbicidal Activity To evaluate their herbicidal activity, compounds according to the invention were tested using a representative range of plants: maize, Zea may. (Mz); rice, Oryza sativa (R); barnyard grass, Echinochloa 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 fall into two categories, pre-emergence and post-emergence. The pre-emergence tests involved spraying a liquid formulation 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 seedling 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 900 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 indicating growth as untreated control, and a rating 9 indicating death. An increase of 1 unit on the linear scale approximates to a 10% increase in the level of effect.

The results of the tests are set out in Table 3 below, in which the compounds are identified by reference to the preceding examples. A blank space in Table 3 below corresponds to a rating 0.

Table 3

Compound of Soil drench 10/kg/ha Dosage Foliar spray Pre-emergence Ex. No. Mz R BG O L M SB S kg/ha Mz R BG O L M SB S Mz R BG O L M SB S 9 9 8 8 8 5 9 9 9 9 2 2 7 9 9 8 1 2 3 8 7 1 1 4 10 6 4 5 8 3 3 6 5 1 7 1 2 2 11 5 7 7 7 5 4 7 8 8 4 9 9 7 4 1 1 2 4 7 1 1 1 3 2 12 4 8 7 6 5 4 6 9 6 2 3 7 8 4 1 1 2 4 7 4 1 3 2 1 Table 3 (continued)

Compound of Soil drench 10/kg/ha Dosage Foliar spray Pre-emergence Ex. No. Mz R BG O L M SB S kg/ha Mz R BG O L M SB S Mz R BG O L M SB S 13 5 3 2 3 3 1 1 1 1 1 1 1 14 5 8 8 8 5 3 7 8 7 2 3 7 8 8 1 2 3 2 2 15 8 5 2 7 3 5 7 5 5 1 5 2 5 1

Claims

CLAIMS 1. A compound of the general formula I:

wherein R represents a hydrogen atom, or an optionally-substituted alkyl, acyl, alkenyl or alkynyl group or an inorganic or organic cation; R or R represents a hydrogen atom or a straight-chain alkyl group having 1 to 3 carbon atoms; the other of R and R represents a straight-chain alkyl group having 1 to 3 carbon atoms; and R and R4 each independently represents an optionally-substituted alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl or phenyl group.
2. A compound as claimed in claim 1 wherein R represents a hydrogen atom.
3. A compound as claimed in claim 1 or 2, wherein R1 and R2 are each independently a methyl, ethyl or n-propyl group.
4. A compound as claimed in claim 1, 2 or 3, 3 4 wherein R3 and R4 are each independently an alkyl, alkenyl or haloalkenyl group.
5. A compound as claimed in claim 4, wherein R3 is an alkyl group and R4 is an alkyl or alkenyl group.
6. A process for the preparation of a compound of formula I as claimed in any one of the preceding claims comprising reacting a compound of formula II:

where R11 R2 and R3 are as defined in claim 1 with hydroxylamine to give an intermediate oxime derivative of formula I as defined in claim 1 except that R4 is a hydrogen atom and reacting this intermediate oxime with a compound of formula R4-L wherein R4 is as defined in claim 1 and L is a leaving group to give a compound of formula I, or by reacting a compound of formula II as defined above with a hydroxylamine derivative of formula H2N-O-R4, or an acid salt thereof, where R4 is as defined in claim 1.
7. A compound of formula I when prepared by the process of claim 6.
8. A compound of formula II as defined in claim 6.
9. A process for the preparation of a compound of formula II as defined in claim 6 comprising reacting a compound of formula III:

where R and R are as defined in claim 1, with an acid of formula R COOH, where R is as defined in claim 1, or a salt, anhydride or acid halide thereof under suitable conditions to effect acylation to give a compound of formula (it).
10. A herbicidal composition comprising a compound of formula I, as claimed in any one of claims 1 to 5 or 7 together with at least one carrier.
11. The use of a compound according to any one of claims 1 to 5 or 7, or of a composition according to claim 10 in combating undesired plant growth.
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 one of claims 1 to 5 or 7, or a composition as claimed in claim 10.