NL193944C - Weed control agents based on 2- 1- (3-chloro-alloxyamino) -alkylidene-5-alkylthioalkyl-1,3-cyclohexanedione. - Google Patents

Description

1 193944

Weed control agents based on 2- [1- (3-trans-chloro-alloxyamino) -propylidene] -5- (2-ethylthiopropyl) -1,3-cyclohexanedione

The invention relates to trans-2- [1- (3-trans-chloro-alloxyamino) -propylidene] -5- (2-ethylthiopropyl) -5 1,3-cyclohexanedione and its salts and to its use as herbicides.

U.S. Patent 4,440,566, issued April 3, 1984, discloses compounds of formula 1, wherein R is preferably an alkyl group of 1-3 carbon atoms, especially ethyl or propyl; R1 is in particular 3-trans-chlorallyallyl or 4-chlorobenzyl; R2 and R3 are preferably each an alkyl group of 1-3 carbon atoms or one of the groups R2 and R3 is a hydrogen atom and the other is an alkylthioalkyl group of 2-8 carbon atoms and most preferably R2 and R3 are each methyl or one of the groups R2 and R3 is hydrogen and the other 2-ethylthiopropyl.

This patent also teaches that these compounds have herbicide activity against grasses and are safe for broadleaf crops.

It has been found that one of the group of compounds mentioned in US Patent 4,440,566 (ie of the present Formula 2) exhibits a surprisingly better herbicide activity than the homolog of Formula 1 wherein R is propyl (Compound No. 54, US-A -4,440,566), against Digitaria sanguinalis (finger grass), Sorghum halepense (chaff), Setaria glauca (yellow needle) and Echinochloa cruss-galli (cormorant).

In addition to exhibiting the pre-emergence activity, the compound has excellent post-emergence herbicide activity against hand grass, coniferous grass, finger grass, spontaneously emerging maize, spontaneously emerging sorghum, jack's paw, broad-leaf signal grass, sticky herb, red rice, sprangletop, seed seed chaff and chaff of corn from rhizome.

The compound of formula 2 exhibits excellent phytotoxicity against grasses even at very low amounts used and can be safely used in those amounts over broadleaf crops. Therefore, the compound is especially useful for controlling grassy weeds in broadleaf crops and in particular for controlling grassy weeds in soybean crops.

The invention also includes suitable salts of the compound of formula 2.

As is known, compounds of the type of formula II exist as tautomers. The compounds also have two asymmetric carbon atoms and can also exist as optical isomers. Formula 2 is intended to include the various tautomeric forms and the individual optical isomers as well as mixtures thereof and the various tautomeric and optical isomers as well as mixtures thereof are part of the invention.

The invention also relates to a herbicide composition comprising a suitable carrier and an effective amount of weed killer for the compound (s) according to the invention or mixtures thereof.

The invention also relates to a method for preventing or controlling the growth of undesired grassy plants, which method of treating the growing medium and / or the foliage 40 of such plants with an amount of the compounds effective for pest-killing according to the invention or mixtures thereof.

The invention further relates to a method of regulating plant growth which treats the growing medium and / or the foliage of such plants with an amount of the compound (s) effective to control plant growth in deviation from the normal growth pattern. invention or mixtures thereof.

The compound of formula 2 can be readily prepared by the process shown in the scheme of Figure 1, wherein R 1 is 3-trans-chlorallyallyl in ways known for analogous oximes (see: US-A-4,440,566).

This process can be easily performed by contacting compound (3) with 3-trans-50 chloroallyloxyamine (4), preferably in an inert organic solvent.

Typically, this process is performed at temperatures between about 0 and 80 ° C, preferably from 20 to 40 ° C, for 1 to 48 hours, preferably 4 to 12 hours, using 1-2, preferably 1.05- 1.2 moles of 3-trans-chloroallyloxyamine (4) per mole of compound (3). Suitable inert organic solvents that can be used are, for example, methanol, ethanol, diethyl ether and 55 dichloromethane. Two-phase systems with water and an immiscible organic solvent (e.g. hexane) and suitable mixtures thereof can also be used.

Trans-chlorallyloxyamine is a known compound and can be prepared by known methods, for example 193944 2 as described in U.S. Patent 4,440,566. For convenience, a transchloroallyloxyamine hydrochloride can be used, whereby the salt is neutralized in situ with an alkali metal alkoxide.

The starting materials of formula III can also be prepared according to the general method described in US patent 4,440,566.

The appropriate salts of compound 2 can be prepared by conventional methods, for example, by reacting the compound of formula 2 with a base such as, for example, sodium hydroxide or potassium hydroxide with the desired cation. Other variations in the cation of the salt can also be brought about by ion exchange with an ion exchange resin of the desired cation.

10 General process conditions

The reaction product can be recovered from the reaction mixture by any suitable separation and purification method such as, for example, chromatography. Suitable separation and purification methods are illustrated in the examples below.

Generally, the above-described reactions are carried out as liquid phase reactions and therefore the pressure is irrelevant except for the temperature (boiling point) when reactions are conducted at reflux. Therefore, these reactions are typically conducted under pressures of 300 to 3000 mm of mercury (40-400 kPa) and are conveniently conducted under atmospheric (101 kPa) or locally prevailing pressure.

It should be noted that when typical or preferred process conditions (eg reaction temperatures, times, molar ratios and reactants, solvents, etc.) are stated, other process conditions could also be adhered to. The optimal reaction conditions (e.g., temperature, reaction time, molar ratios, solvents, etc.) may vary according to the particular reagents or organic solvents used, but may be determined by ordinary optimization methods.

When mixtures of optical isomers are obtained, the individual optical isomers can be obtained by conventional separation procedures. Geometric isomers can be separated by conventional separation methods depending on differences in physical properties between the geometric isomers. In general, however, it is preferable to run the reaction with the desired isomeric starting material.

The term "suitable salts" refers to salts which do not significantly adversely affect the herbicide properties of the parent compound. Eligible salts are the cation salts of lithium, sodium, potassium, alkaline earth metals, copper, zinc, ammonia and quaternary ammonium ions.

The term "room temperature" refers to 20-25 ° C.

The compound of formula II and its salts have both a pre-emergence and a post-emergence herbicide activity and especially show good herbicide activity against grasses. The compounds and especially good phytotoxicity to Setaria sp. (needle), Cynodon sp. (hand grass, Panicum texanum (finger grass), Sorghum vulgare (chaff) and spontaneously emerging reais (maize), which weeds are generally difficult to control.

Generally, the post-emergence herbicide compounds are applied directly to the 40 leaves or other plant parts. For pre-emergence applications, the herbicide compounds are applied to the growth medium or to the expected growth medium for the plant. The optimal amount of herbicide compound or composition varies according to the particular plant species and the degree of plant growth if present and the part of the plant to be contacted and the degree of contact. The optimal dosage may also vary with the general location or environment 45 (e.g., sheltered surfaces such as greenhouses versus open surfaces such as fields) and the type and degree of control desired. Generally, the present compounds are used both before and after emergence control in amounts of from about 0.02 to 60 kg / ha, preferably from about 0.02 to 10 kg / ha.

Although the compounds can theoretically also be used undiluted, they are generally used in practice as a composition comprising an effective amount of the compound (s) and an acceptable carrier. An acceptable or suitable carrier (acceptable from an agricultural point of view) is a carrier which does not significantly adversely affect the desired biological effect of the active compounds, except to dilute it. Usually the composition contains 0.05 to 95% by weight of the compound of formula 2 or mixtures thereof. Also, concentrates with high 55 concentrations can be made for dilution before application. The carrier can be a solid, liquid or aerosol. The actual compositions can be in granular, powder, dust, solution, emulsion, slurry and aerosol form.

3 193944

Suitable solid carriers that can be used are, for example, natural clays (such as kaolin, attapulgite, montmorillonite, etc.), talc, pyrophyilite, diatomaceous earth, synthetic fine silica, calcium aluminosilicate, tricalcium phosphate and the like. Organic carriers such as, for example, walnut husk flour, cotton seed casings, wheat flour, wood flour, wood bark flour can also be used as carriers. Suitable liquid diluents that can be used are, for example, water, organic solvents (for example, hydrocarbons such as benzene, toluene; dimethyl sulfoxide, kerosene, diesel oil, fuel oil and naphtha). Suitable aerosol carriers that can be used are conventional aerosol carriers such as halogenated alkanes.

The composition may also contain various auxiliaries and surfactants that increase the rate of transport of the active compound to the plant tissue, such as, for example, organic solvents, wetting agents and oils, and in the case of compositions intended for the pre-emergence application , agents which decrease the leachability of the compound or otherwise increase the stability in the soil. Crop oils such as, for example, soybean oil, paraffin oils and olefinic oils are particularly advantageous as carriers or additives in that they increase phytotoxicity. The composition may also contain various suitable adjuvants, stabilizers, conditioners, insecticides, fungicides and, if desired, other herbicidal compounds.

A suitable concentrate composition that can be used includes 23 to 27% by weight of the active herbicide of the invention, 2 to 4% by weight of an emulsifier, for example, calcium alkyl benzene sulfonate or octyl phenol ethoxylate; or mixtures thereof and 70-75% of an organic solvent, for example xylene. Before use, the concentrate is mixed with water and preferably a crop oil and used as a water emulsion containing 0.5 to 2% of a vegetable oil, for example soybean oil, and mineral paraffinic oils and olefinic oils. Advantageously, the herbicide is used as a water emulsion which contains 0.02-0.6 wt.%, Preferably 0.07-0.15 wt.% Of the herbicide according to the invention, 0.001-0.01 wt.% Of a emulsifier, containing 0.08-2.5 wt% of an organic solvent and 95 to 99 wt% water. Preferably, the composition also contains 0.25 to 2% by weight of a crop oil. The composition can be easily prepared by mixing the concentrate composition with 1/4 to 1/2 of the desired amount of water, then adding the crop oil and finally the remaining amount of water. If no crop oil is used, the water and the concentrate composition are simply mixed together.

Further insight into the invention can be obtained with the following non-limiting preparation (s) and examples, in which, unless expressly stated otherwise, all temperatures and temperature ranges are indicated in degrees Celsius and the term '' room temperature 'refers to 20-25 ° C. The term "percent" or "%" refers to percent by weight and the term "mol" or "mill" refers to gram moles. The term "equivalent" refers to an amount of reagent in moles equal to the number of moles of 35 previous or next reactant mentioned in the relevant example in terms of final mill or final weight or volume, and examples are also repeated as necessary to provide additional starting material for subsequent examples.

Example I

40 2- [1 - (3-Trans-chloroallyloxyamino) propylidene] -5- (2-ethylthiopropyl) -1,3-cyclohexanedione

In this example, 17.2 g (0.0636 mol) 2-propionyl-5- (2-ethylthiopropyl) -1,3-cyclohexanedione, 0.9 g (0.0153 mol) acetic acid and 10.9 g (0 .0757 mol) 3-trans-chloroallyloxyamine in 35 ml water was added to 20 ml hexane and stirred. Then, a solution of 5 wt% sodium hydroxide in water was slowly added over about 15 min until 3.0 g (0.0757 mol + small excess) of sodium hydroxide was added 45 and the pH of the reaction mixture was about 6. The mixture was heated and kept at 40 ° C for about 2.5 hours and then cooled back to room temperature. The organic layer (i.e., hexane layer) was separated and washed with 10 ml of 5% hydrochloric acid, then 6.25 wt% aqueous sodium hydroxide was added to pH 12. The water layer was separated and mixed with 25 ml of hexane; the pH was adjusted to 5.4 by adding 36 wt% hydrochloric acid dropwise in an ice bath. The organic phase was separated, dried over magnesium sulfate and then evaporated to yield 18.0 g of crude product. The crude product was purified by column chromatography over silica gel with hexane: dichloromethane as eluent to afford the purified title compound as an oil.

Elemental Analysis: Carbon: Calc. 56.73%, found. 56.63%; hydrogen: ber. 7.28%, found. 7.55%; nitrogen: ber. 55 3.89%, found. 3.55%.

193944 4

Example II

Sodium 2- [1 - (3-trans-chloroallyloxyamino) propylidene] -5- (2-ethylthiopropyl) -3-oxo-1-cyclohexene-1-olate

This example illustrates a method that can be used for the preparation of the title compound.

A solution of 0.01 mole sodium hydroxide in 2 ml water was added at room temperature to a solution of 0.01 mole 2- [1- (3-trans-chloroallyloxyamino) propylidene] -5- (2-ethylthiopropyl) -1, 3-cyclohexanedione. When the reaction was completed, the solvents were evaporated under reduced pressure to yield the 1-hydroxy sodium salt of 2- [1- (3-trans-chloroallyloxyamino) propylidene] -5- (2-ethylthiopropyl) -3-oxo-1-cyclohexene-1 -ol was obtained.

10

Example III

In this example, the title compound of Example I, ie 2- [1- (3-trans-chloro-alloxyamino) -propylidene] -5- (2-ethylthiopropyl) -1,3-cyclohexanedione was tested for pre-emergence according to the procedure described below. and post-emergence phytotoxic activity against a variety of grasses and broadleaf plants including a cereal and a broadleaf crop.

Pre-emergence herbicide trial

The pre-emergence herbicide activity was determined in the following manner.

Test solutions of the respective compounds were prepared as follows: 355.5 mg Test compound was dissolved in 15 ml of acetone. 2 ml of Acetone containing 110 mg of a nonionic surfactant was added to the solution. 12 ml of this stock solution was then added to 47.7 ml of water containing the same nonionic surfactant at a concentration of 625 mg / l. Seeds of the test crop were planted in a pot of soil and the test solution was uniformly sprayed over the soil surface at a dose of 27.5 micrograms per cm 2 unless otherwise specified in the following tables. The pot was poured and placed in a greenhouse. The pot was watered from time to time and examined for three weeks for the emergence of seedlings, the health of the emerging seedlings, etc. At the end of this period, the herbicidal activity of the compound was rated based on the physiological observations. A scale from 0 to 100 was used, with 0 representing no phytotoxicity and 100 representing complete death. The results of these tests are summarized in Table A.

30 Post-emergence herbicide trial

The test compound was formulated in the same manner as described above for the pre-emergence test. This formulation was applied evenly on two similar pots with plants 5 to 7.5 cm high (except wild oats, soybeans and water grass, which were 7.5 to 10 cm high) (15 to 25 plants per pot) at a dose of 27 1.5 micrograms of test compound per cm 2 unless otherwise noted in the following tables. After the plants dried, they were placed in a greenhouse and then poured from time to time at the base as needed. The plants were periodically examined for phytotoxic effects and physiological and morphological responses to treatment. After three weeks, the herbicidal activity of the compound was evaluated based on these observations. A scale of 0 to 100 was used, with 0 referring to no phytotoxicity and 100 referring to complete death. The results of 40 of these experiments are summarized in Table B, in which Chemopodium album (white goosefoot)

Brassica arvensie (mustard)

Amaranthus retroflexus (parrot herb)

Glycine max (soybean) 45 Echinochloa crus-galli (cepine)

Digitaria souguinalis (finger grass)

Avena fatua (wild oats)

Oryza satira (wild rice)

Sorghum halepense (chaff) 50 Cyperus esculentus (almond)

Setaria glauca (yellow needle) 5 193944

TABLE A

Pre-emergence herbicide activity 5 Applied dose: 27.5 micrograms / cm2, unless otherwise indicated Broad-bred plants% Phytotoxicity Grasses% Phytotoxicity Compound No White Mustard Papaya Soybean Cepee Finger Grass Wild Rice Gooseweed Oats 10 Feet 1 25 30 25 30 100 100 100 100

TABLE B

15 Post-emergence herbicide activity

Applied dose: 27.5 micrograms / cm2, unless otherwise indicated broad-bred plants% phytotoxicity grasses% phytotoxicity compound no. White mustard papaya soybean coot leg finger grass wild rice guinea herb oats foot 1 30 45 40 40 100 100 100 100 25

Example IV

In this example, the title compound of Example I of the present invention ("1") post-emergence herbicidal activity was tested at moderately low dose in addition to the known butylidene homologue, ie 2- [1- (3-trans-chloroallyloxyamino) butylidene] -5 - (2-ethylthiopropyl) -1,3-cyclohexanedione.

The tests were carried out in the same manner as described in Example II above, except that the application amounts indicated in Table C were used and four replicate pots instead of two were used per test. The mean results from the four replicates were reported in Table C, with 0 indicating no phytotoxicity and 100 indicating complete death. In general, phytotoxicity below 20 to 30% is not considered useful, because the plant can usually grow over this amount of damage.

TABLE C

Post-emergence herbicide activity 40 -

Tests with moderately low dose of broad-bridal plants% phytotoxicity grasses% phytotoxicity compound no. * Dosage white mustard papaya soybean fingergrass leg wild rice 45 γ / cm2 ** guinea herb oats footprint 1 1.8 0 3 0 7 100 100 98 98 1 0 .7 0 0 0 2 100 100 80 85 C-1 1.8 0 0 0 NT 87 100 95 97 50 C-1 0.7 0 0 0 N.T. 60 98 80 87 N.T. = not tested, but based on other tests, the comparative compound at this dosage is also safe for soybeans.

55 1 = 2- [1- (3-trans-chloro-alloxyamino) propylidene] -5- (2-ethylthiopropyl) -1,3-cyclohexanedione (invention) C-1 = 2- [1- (3-trans-chloro-alloxyamino) butylidene] -5- (2-ethylthiopropyl) -1,3-cyclohexanedione (US-A-4,440,566) 193944 6 ** γ / cm2 = micrograms per cm2.

As shown in Table C, Compound 1 was significantly better compared to Compound C-1 against finger grass, even at moderately low dosages. The superiority of compound 1 becomes more apparent at the low dosages used in Example 4.

Example V

In this example, the title compound ("1") was tested for post-emergence herbicide activity at a very low dose in addition to 2- [1 - (3-trans-chloroallyloxyamino) butylidene] -5- (2-ethylthiopropyl) -1,3-cyclohexanedione (C-1 ") 10 and the commercially available herbicide Sethoxydim (" C-2 ") (2- [1- (ethoxyamino) butylidene] -5- (2-ethylthiopropyl) -1,3-cyclohexanedione) against a range of unwanted grasses.

The tests were performed in the same manner as described in Example III, except that the dosages indicated in Table D were used. The results of these tests are summarized in Table D, where 0 indicates no phytotoxicity and 100 indicates complete death. In general, phytotoxicity below about 20 to 30% is not considered meaningful because the plant can usually grow over this amount of damage.

TABLE D

20 Post-emergence herbicide activity Tests with low dose grasses% phytotoxicity cultivated crops% phytotoxicity 25 compound no. 93 1 0.11 63 90 46 92 78 0 0 83 30 1 0.05 40 60 6 63 66 0 0 71 1 0.02 5 8 0 21 0 0 0 1 C-1 0.28 55 96 60 68 80 0 0 78 C-1 0.11 25 70 43 43 53 0 0 70 C-1 0.05 15 40 26 21 40 0 0 40 35 C-1 0.02 0800000 10 C-2 0.28 53 80 36 73 68 0 0 63 C-2 0.11 16 68 16 31 48 0 0 41 C-2 0.05 10 20 0 0 10 0 0 10 C-2 0.02 0000 000 0 40 - * γ / cm2 = micrograms per cm2

As shown in Table D, Compound 1 except wild oats and almond (Cyperus esculentus) 45 was better than Comparative C-1 over each of the other weeds tested. Compounds 1 and C-1 were approximately equivalent to wild oats and both compounds were ineffective against earth almonds at the dosages used. Compounds 1 and C-1 were both better than Compound C-2.

In terms of dosages required to effect equivalent bars, an application amount of compound 1 of 0.11 g / cm2 was approximately equivalent to an application amount of compound C-1 of 0.28 g / cm2 to combat finger grass and jack-of-all-trades. An application amount of compound 1 of 0.05 g / cm2 was approximately equivalent with an application amount of compound C-1 of 0.28 g / cm2 to control yellow needle and an application amount of compound 1 of 0.11 g / cm2 was better than an application amount of compound C-1 55 of 0.28 g / cm2 for controlling rovine grist.

Claims (3)

Herbicide composition comprising an effective herbicide effective amount of a 2- [1- (3-trans-chloro-alloxyamino) -alkylidene] -5- (2-ethylthiopropyl) -cyclohexane-1,3-dione and a suitable carrier characterized in that the compound according to claim 1 is used. Herbicide composition according to claim 2, characterized in that vegetable oil is used as the carrier. Herbicide composition containing 0.02-0.6 wt% of a compound according to claim 1; 0.001-0.15 wt% of an emulsifier; 0.08-2.5 wt% of an organic solvent and 95 to 99 wt% water. Hereby 1 sheet drawing