HU187689B - Selective hebicide compositions and process for preparing the active substances - Google Patents

Abstract

SUMMARY OF THE INVENTION The present invention relates to a selective herbicidal composition comprising from 0.1 to 90% by weight of active compound of formula (II), wherein R is C 1-4 alkyl and X is chloro, bromo or iodo and to 100% by weight. containing at least one solid or liquid carrier or diluent, surfactant and other excipients in the required amount. The present invention also relates to a process for the preparation of the compounds of formula (II) wherein a compound of formula (III) wherein Q is a tertiary base and X is a chloro, bromo or iodo atom with a carbonic acid derivative of the formula (IV): wherein R is C 1-4 alkyl and Z is chloro or bromo. X RO-COO- / O CN -1-

Description

SUMMARY OF THE INVENTION The present invention relates to a selective postemergent herbicidal composition and a process for the preparation of the active compounds.

The active compounds of the herbicidal compositions of the present invention are represented by the general formula (II).

In the formula (II), R is a C 1-4 alkyl group and X is a chlorine, bromine or iodine atom.

The substituent may be straight or branched, preferably methyl or ethyl.

No. 154,690. Hungarian Patent Specification No. 4,197,195 discloses compounds of formula I having herbicidal activity.

In the general formula (I)

R ¹ and R ² are the same or different and are hydrogen or halogen, R ^{3 is} halogen, R ^{4 is} hydrogen, acyl or alkoxycarbonyl, alkali or alkaline earth metal, ammonium ion or organic amine, R ^{5 is} hydrogen or halogen or nitro when at least one and at most two of R ¹ , R ² and R ⁵ are hydrogen, with the proviso that (1) when R ¹ and R ^{2 are} hydrogen and R ³ and R ^{5 are} iodine, then R ^{4 may} not represent hydrogen, acetyl, sodium or potassium; and (2) when R ¹ and R ^{2 are} hydrogen and R ³ and R ^{5 are} both bromo or chloro, then R ^{4 may} not represent hydrogen, acetyl or sodium.

No. 154,690. The Hungarian patent does not specifically describe the compounds of formula II according to the invention and their activity.

It has now been found that formulations containing the compounds of formula (II) according to the invention are useful postemergently in the selective control of weeds since the phytotoxic effects of the compounds of formula (II) on monocots and dicots are significantly different. The application of the active compounds of the formula (II) at a dose of 2 kg / ha postemergently causes an average of 20% for the monocots and 80% for the dicots.

However, the known 3,4-dibromo-4-hydroxybenzonitrile (Bromoxynil) and the octanoic acid ester (Brominal) of the formula I are very damaging to monocotyledons (77%) and to dicotyledons (almost 89%).

No. 154,690. According to the teachings of the Hungarian patent application, the active compounds of the formula I can be applied at a dose of 0.28-0.56 and a maximum of 0.56-1.68 kg / ha without damaging the crop plants, however, the active compounds of the general formula I 2.24-4.48 kg / ha are required to achieve a herbicidal effect.

The active compounds of the formula II according to the invention can be used even at a dosage of 6.2 kg / ha for maize weed control without damaging the crop.

It has also been found that the active compounds of the formula II are more effective in controlling the triazine-resistant Amaranthus and Chenopondium species, which are increasingly problematic in maize cultures, than the known Brominal.

The impact studies were carried out on small plots with maize stock management as follows:

The sowing was preceded by plowing and disc cultivation of 25-32 cm, no basic herbicide treatment was applied. Postemergent treatment was carried out at a one-month stage in maize at 3001 / ha water and at doses of 0.5-1.0-1.5 kg active ingredient / ha. For the treatment we used the following composition:

(2-Bromo-4-cyano-6-nitrophenyl) methyl carbonate 80% w / w Sodium Naphthalenesulphonic acid (Wettol NT 1) 3% w / w Sodium lignin sulphonic acid (Borresperse B) 5% w / w Silica (Neuburgi chalk) 12 s%

The spraying was done with Tee-Jet 11 008-11 010 nozzles at 2.0-2.5 atm. under pressure. A standard formulation of 3,5-dibromo-4-hydroxybenzonitrile octanoate (active ingredient B) (Brominal 32 EC) was used as a standard at 0.66 kg active ingredient / ha. At the time of treatment, the stage of development of dominant weeds was as follows.

Amaranthus retroflexus 20 cm

Amaranthus chlorostachys 20 cm

Chenopodium album 15-20 cm

Hibiscus trionum 4-6 cm

Stachys annua 4-8 cm

Malva does not grow 4-6 leaves

Evaluation was performed on day 10 after treatment with

Table 1 contains. Brominal, used as a standard, caused mild phytotoxic symptoms on maize.

Evaluation was performed on the EWEC scale. According to this value 1 is excellent (100%), 2 is very good (98%), 3 is good (95%), 4 is satisfactory (90%), 5 is questionable (82%), 6 is not satisfactory (70%) ), 7 means bad (55%), 8 means very bad (30%), 9 means useless (0%) weed control.

Table 1

dose active ingredient kg / if THE retro- FLEXUS THE. chlo- rosta- Chyše C. album H. trio- num s. annua M. neglee- ta B, 0.66 5 6 3 5 .6 4 0.5 3 4 2 3 6 4 A 1.0 2 2 1 3 4 3 1.5 2 2 1 3 4 3

The active compounds of formula (II) according to the invention are also suitable for use in a variety of vegetable plants, e.g. peas, onions, carrots, etc. - also post-emergence weed control.

Detailed laboratory experiments were conducted to determine whether differences in activity and selectivity between the compounds of the present invention and bromoxynil in the field were demonstrated at the level of mechanism of action and mode of action. The effect of the compounds on the photosynthetic activity was investigated, since the dihalogenated hydroxybenzonitrile herbicides (3,5-diiodo-4-hydroxybenzonitrile [Ioxynil], 3,5-dibromo-4-hydroxybenzonitrile [Bromoxynil] their primary attack point is in the photosynthetic electron transport chain

In addition, our galaxies were extended to investigate simple (elongated) growth and membrane function (active K ⁺ -influx, electrolyte efflux).

In the growth assay (elongation of the root of lettuce seedlings), we have found that dibromo derivatives exhibit activity similar to that of plant growth regulating hormones: they stimulate root elongation at low concentrations and strongly inhibit them at higher concentrations. Similar growth-regulating activity has so far only been shown for bromoxynil 2,4-D esters (Heywood 1966 Chem. And Ind. 1946-1952). The effect of (2-bromo-4-cyano-6-nitrophenyl) alkyl carbonates is different in the lettuce root growth test, inhibition after initial inefficiency, and growth inhibition (see Example 3).

Comparing the results of growth and membrane function tests, it can be concluded that the differences in the biological activity spectrum of the compounds of the present invention and the known benzonitrile herbicides are due to differences in their uptake and translocation in the plant.

From the photosynthetic activity of our monocotyledonous and dicotyledonous test plants (wheat and spinach), the following can be deduced from in vivo CO ₂ fixation on intact plants and dichlorophenol indophenol (DCPIP) reduction with isolated chloroplasts. The dibromo-substituted compound acts in the same way in the in vitro system and in the intact plant on dicotyledonous potency and on monocotyledonous medium. Bromine nitro-substituted compounds act on dicotyledons in the same way as bromoxynil, but on monocotyledons to a lesser extent than bromoxynil (see Example 4).

In laboratory tests to measure the activity of photosynthesis, the selectivity of bromo-nitro-substituted compounds in mono- and dicotyledons is higher than that of dibromo-compounds.

The active compounds of formula (II) in the form of pesticidal compositions, wettable powders, pastes, emulsion concentrates, etc., are used in plant protection. is used. The formulations may contain, in addition to the active ingredient, customary solid or liquid carriers or diluents, surfactants, and other excipients.

The compositions may contain from 0.1 to 90% by weight of the active ingredient. The compositions may be diluted at the site of application to the desired concentration of the active ingredient.

The present invention also relates to a method of treating post-emergence weed control of maize, cereal and vegetable crops.

According to the invention, the weed control in the above cultures is carried out post-emergence with a composition containing from 0.1 to 90% by weight of the compound of the formula II in a dose of 1 to 4 kg of active ingredient / ha.

The benzonitrile derivatives (II) of the present invention may be prepared by reacting a benzonitrile (III) wherein Q is a tertiary base and X is a chlorine, bromine or iodine atom with a carbonic acid derivative (IV). wherein R is C1-C4 alkyl and Z is chlorine or bromine.

The reaction is preferably carried out in a solvent medium at 20-60 ° C.

The present invention is illustrated by the following examples, but is not limited to the examples.

Example 1 Preparation of (2-Bromo-4-cyano-6-nitrophenyl) methyl carbonate.

121.5 g of 3-bromo-4-hydroxy-5-nitrobenzonitrile are taken up in 650 ml of benzene and 73 ml of triethylamine are added. The resulting solution was reacted with a solution of methyl chloroformate (44 ml) in benzene (75 ml), ca. Drip at 20-25 ° C over 30 minutes. After stirring for two hours at 20-25 ° C, then for one hour at 55-60 ° C, cool, add 100 ml of water, separate and wash the benzene solution with another 100 ml of water. The wash water was extracted once with 50 ml of benzene. The combined benzene solution was dried over anhydrous sodium sulfate and clarified with carbon. After filtration, approx. The reaction mixture was concentrated to half volume and stirred with 1 L of isopropyl ether, the resulting crystalline mass was stirred for one hour in ice water, washed with cold methanol and dried.

Yield: 128 g (85%) of the title compound, mp 118-120 ° C.

By proceeding as described above, using the appropriate compounds of formulas III and IV, the following compounds of formula II are prepared: (2-Chloro-4-cyano-6-nitrophenyl) ethyl carbonate Term. 87%, m.p. 89 ° C (2-iodo-4-cyano-6-nitrophenyl) ethyl carbonate

92%, m.p. 112 ° C (2-bromo-4-cyano-6-nitrophenyl) -isopropyl carbonate Term. 87%, m.p. 79 ° C (2-bromo-4-cyano-6) nitrophenyl) isobutyl carbonate Term .: 80%, m.p. 75 ° C (2-bromo-4-cyano-6-nitrophenyl) ethyl carbonate Term: 87.6%, m.p. 112 ° C

EXAMPLE 2 Comparative greenhouse study of (2-bromo-4-cyano-6-nitrophenyl) methylcarbonate (IIa) and bromoxynil: Test plants were grown in sand in 168 cm ² culture vessels for 20 days and then sprayed with the formulations. aqueous suspension. The effect was evaluated on the 14th day after treatment. In our table, the fresh weight of the plants is given as a percentage of the control:

187,689

test plants Compound (IIa) (50 WP) 2 kg active ingredient / ha Bromoxynil (32 EC) 2 kg active ingredient / ha maize 100 67 wheat 100 68 rye 100 0 millet 100 0 pea 71 0 larkspur 0 0 mustard 0 0 garden cress 0 0 flax 0 0 thistle 0 0 sunflower 0 0 sorrel 0 0 tomato 0 0

Example 3

Salad root growth test

Plants of Lcatuca sativa ("Attraction"), germinated at 25 ° C in the dark, were transplanted into a Petri dish (4 cm ³ solution, 15 plants) in a CaSO ₄ solution containing the test substance. The plants were then exposed to alternating illumination over a period of 14 hours of light and 10 hours of darkness (average temperature 23 ° C). An increase in root length, expressed as a percentage of untreated control, was used for evaluation.

10 ' ⁶ % 10 ^{5 5} M ° / / 0 10 ^{4 4} M ° / o 3-bromo-5-nitro-4-dihydro- methoxy-benzonitrile 88.8 95.4 10.1 (2-bromo-4-cyano-6-nitro- phenyl) methyl carbonate 90.4 72.9 17.9 (2-bromo-4-cyano-6-nitro- phenyl) ethyl carbonate 90.5 87.7 3.7 3,5-dibromo-4-hydroxybenzonitrile 140.6 96.6 7.0 (2,6-dibromo-4-cyano- phenyl) ethyl carbonate 149.6 91.9 35.3

Example 4

Measurement of in vivo CO ₂ fixation of wheat and spinach

In vivo in vivo CO ₂ fixation of leaves was determined using ¹⁴ CO _{2 according} to Sárvári et al. (Physiol. Plant. 36: 187-192, 1976). After the fixation was completed, the radioactivity of the leaves killed by heat treatment was measured by liquid scintillation technique. The data in the table are values expressed as a percentage of control.

spinach wheat 3,5-dibromo-4-hydroxy- benzonitrile 10.7 47.4 (2-bromo-4-cyano-6-nitro- phenyl) -metilkarbonát 11.0 91.0

Example 5

(2-Bromo-4-cyano-6-nitrophenyl) methyl carbonate of formula (IIa) was prepared as a powder sprayer formulation: 80 g of the active ingredient were pre-homogenized followed by 3 g of alkyl naphthalenesulfonic acid Na (Wettol NT 1). After addition of 5 g of low pH lignin sulfonate Na (Borres perse B) and 12 g of technical silica (Neuburgi chalk) to a particle size of less than 10 microns.

Example 6

According to Example 5, a wettable powder composition having the following composition was prepared:

g of (2-bromo-4-cyano-6-nitrophenyl) methyl carbonate, 4 g of alkyl naphthalenesulfonic acid Na, 5 g of lignin sulfonate Na, 1 g of urea, 5 g of Na-silicate.

Example 7 (2-Bromo-4-cyano-6-nitrophenyl) methyl carbonate was formulated as a water-emulsifiable suspension formulation with 50 g of the active ingredient, followed by 5 g of alkanesulfonic acid Ca (Hoe S 1557) and 5 g of fatty alcohol polyglycol. -ether (Genapol 0.050) was re-ground in a pearl mill.

Example 8 g (2-Bromo-4-cyano-6-nitrophenyl) methyl carbonate An emulsion suspension was prepared with 4 g of Atlox 4851 (anionic and nonionic surfactant mixture), 6 g of Atlox 3400, 1 g of organophilic bentonite and 39 g of solvent naphtha. Example 7.

Claims (3)

Patent claims CLAIMS 1. A selective herbicidal composition comprising 0.1 to 90% by weight of the benzonithyl derivative of the formula II as an active ingredient. wherein R is C 1 -C 4 alkyl and X is chlorine, bromine or iodine and from 1 to 25% by weight of a surfactant - preferably alkylnaphthalenesulfonic acid-Na, alkanesulfonic acid-Ca, anionic and nonionic a surfactant mixture, lignin sulfonate Na, fatty alcohol polyglycol ether and a solid or liquid carrier or diluent, preferably silicates, technical silica (Neuburg Chalk), organophilic bentonite, organic solvent, in an amount up to 100% by weight. 2. The composition of claim 1 wherein the active ingredient is (2-bromo-4-cyano-6-nitrophenyl) methyl carbonate. 3. A process for the preparation of a benzonitrile compound of formula II wherein R and X are as defined in claim 1, characterized in that a benzo-41 compound of formula III is used. 187,689 nitrile derivatives wherein Q is a tertiary base and X is chloro, bromo or iodo are reacted with carbon dioxide of formula IV wherein R is C 1-4 alkyl and Z is chloro or bromo.