HU187690B - Herbicide 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 a benzonitrile derivative of formula (II): wherein A is oxygen or sulfur, B is C2-C4alkenyl, O-phenyl, C 1 -C 4 Oalkoxy-C 1 -C 4 alkyl or dimethylamino, X is chlorine, bromine or iodine and contains at least one of the solid or liquid carrier or diluent, surfactant and other excipients necessary for 100 wt% . The invention also relates to a process for the preparation of the compounds of formula (II) by reacting 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 formula (IV). -1-

Description

BACKGROUND OF THE INVENTION The present invention relates to a post-emergent 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), A is oxygen or sulfur, B is C 2 -C 4 -alkenyl, Ο-phenyl, C 1 -C 4 -alkoxy-C 1 -C 4 alkyl or dimethylamino, X is chlorine , bromine or iodine.

The aryl group is preferably phenyl, the alkenyl group is preferably allyl.

The compounds of the general formula (I) which are closest to the active compounds (II) of the herbicidal compositions of the present invention are disclosed in U.S. Patent No. 154,690. Hungarian patent specification.

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 metal or alkaline earth metal, ammonium ion or organic amino, 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, provided that (1) when R 1 and R ^{2 are} hydrogen atoms 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 a hydrogen atom, an ethyl group or a sodium atom.

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 monocotyledons are significantly different. The active compounds of the formula II, when applied in a dose of 2-4 kg / ha postemergently, damage the monocots by an average of 15-25% and the dicots by 70-85%.

However, the known 3,5-dibromo-4-hydroxybenzonitrile (Bromoxynil) and octanoic acid ester (Brominal) of formula (I) are very damaging to monocotyledons (77%) and 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 applied even at a dose of 7.0 kg / ha for maize weed control without damaging the crop. The effect studies were performed in a greenhouse.

For the treatment we used the following composition:

(2-Bromo-4-cyano-6-nitrophenyl) allyl carbonate 80% sodium naphthalenesulfonic acid sodium (Wettol NT 1) 3% lignin sulfonic acid sodium (Borresperse B) 5% silicon dioxide (Neuburg chalk) 12 s %

A standard formulation of 3,5-dibromo-4-hydroxybenzonitrile octanoate (active ingredient B) (32 EC for bromine) was used as a standard.

The results are described in Example 2.

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 dihalogenated hydroxylbenzonitrile herbicides (3,5-diiodo-4-hydroxybenzonitrile (Ioxynil), 3,5-dibromo-4-hydroxybenzonitrile (Bromoxynil) are generally accepted as the primary attack point From the photosynthetic activity of one of our dicotyledonous test plants (wheat and spinach), in vitro CO ₂ fixation on intact plants and dichlorophenol-indophenol (DCPIP) reduction in isolated chloroplasts, the following were determined: systemic and intact plants act equally on dicotyledonous, moderately potent monocotyledonous compounds. in these dedicated laboratory tests, the selectivity of the bromo-nitro-substituted compounds between the mono- and dicotyledons is higher than that of the 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 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 formulations may be diluted at the site of application to the desired drug concentration.

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 in a postemergent manner with a composition containing from 0.1 to 90% by weight of the active compound of the formula II in a dose of 1 to 5 kg of active ingredient / ha.

The compounds of formula (II) of the present invention may be prepared by reacting a compound of formula (III) wherein Q is a tertiary base and X is chloro, bromo or iodo with the carbonic acid derivative of formula (IV). 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.

-2. 187,690

Example 7 Preparation of (2-Bromo-4-cyano-6-nitrophenyl) phenyl carbonate. 121.5 g of 3-bromo-4-hydroxybenzonitrile are taken up in 650 ml of benzene and 73 ml of triethylamine are added. The resulting solution was reacted with 44 ml of a solution of phenyl formate of chloroformate in 75 ml of benzene, ca. Drip at 20-25 'over 30 minutes. After stirring for two hours at 20-25 ° C, then for 1 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. Concentrate to half volume and add 1 liter of isopropyl ether with stirring, the precipitated crystal mass is stirred in ice water for one hour, filtered off, washed with cold methanol and dried.

Production; 92 s% op. 86 'C.

The following esters were prepared as described in Example 1:

2. (2-Bromo-4-cyano-6-nitrophenyl) allyl carbonate; 87 s%, m.p. 87 '

3. (2-Bromo-4-cyano-6-nitrophenyl) -2-methoxyethyl carbonate; 85%, m.p. 100 '

4. 6- (2-Bromo-4-cyano-6-nitrophenyl) -S-ethylcarbonate term; 83%, m.p. 109 '

5. O- (2-Bromo-4-cyano-6-nitrophenyl) -N, N-dimethylthiocarbamate; 95%, m.p. 135 °

6. (2-Chloro-4-cyano-6-nitrophenyl) phenyl carbonate; 92%, m.p. 89 °

7. (2-Bromo-4-cyano-6-nitrophenyl) phenyl carbonate; 92%, m.p. 86 '

Example 2 Comparative greenhouse test of compound (IIa) (2-bromo-4-cyano-6-nitrophenyl) allyl carbonate and bromoxynil. Test plants were grown in sand in pots of 168 cm ^{2 for} 20 days and then sprayed with an aqueous suspension of the molded formulations. The effect was evaluated on the 14th day after treatment.

In our table, the fresh weight of the plants is shown as% of control.

_B._

If Compound Bromoxynil Test Plant (50 WP) 2 kg 32 EC 2 kg active ingredient / ha active ingredient

Maize 100 67 Wheat pigweed 10o 68 (Amaranthus retroflexus) 18 20 White mustard (Sinapis alba) 0 0 Muhar (Setaria italica) 26 26 Bitter grass (Polygonum lagratifolium) 10 10

Example 3

Measurement of in vivo wheat and spinach leaves in the CO _z -fixációjának vehicle CO ₂ fixation was determined using ¹⁴ CO _2, according Sárvári et al (Physiol Plant, 36187-192., 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) -phenyl carbonate 6 69 (2-bromo-4-cyano-6- nitro-phenyl) - -allilkarbonát 11 93

Example 4

(2-Bromo-4-cyano-6-nitrophenyl) allyl carbonate of formula IIa was prepared as a powder spray formulation:

g of the active ingredient were pre-homogenized and then added with 3 g of alkyl naphthalene sulfonic acid Na (Wettol NT 1), 5 g of low pH lignin sulfonate Na (Borres perse B) and 12 g of technical silica (Neuburg chalk) to a particle size of less than 10 microns. It was milled.

Example 5

According to Example 4, a wettable powder composition having the following composition was prepared:

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

Example 6

(2-Bromo-4-cyano-6-nitrophenyl) allyl carbonate of formula (IIa) was prepared as a water-emulsifiable suspension formulation:

After the addition of 5 g of alkanesulfonic acid Ca (Hoe S 1557) and 5 g of fatty alcohol polyglycol ether (Genapol 0-050) to the pearl litter, the active ingredient was homogenized.

Example 7 A suspension of g (2-bromo-4-cyano-6-nitrophenyl) allyl carbonate, 4 g of Atlox 4851 (a mixture of anionic and nonionic surfactants), 6 g of Atlox 3400, 1 g of organophilic bentonite and 39 g of solvent naphtha was prepared as described in Example 6.

Claims (3)

CLAIMS 1. A selective herbicidal composition comprising 0.1 to 90% by weight of the benzonitrile compound of the formula II as an active ingredient. A is oxygen or sulfur B is C 2 -C 4 -alkenyl, O-phenyl, C 1 -C 4 -alkoxy-C 1 -C 4 alkyl or dimethylamino 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 surfactant mixtures, lignin sulfonate Na, fatty alcohol polyglycol; ether, and a solid or liquid carrier or diluent in an amount of 100% by weight, preferably silicates, technical silica (Neuburgian chalk), organophilic bentonite, organic solvent, water. 2. The composition of claim 1, with figure _5, characterized in that as an active ingredient (2-bromo-4-cyano-6-nitro) phenyl carbonate. 3. A method (II) benzonitrile of the formula - wherein A, B and X are as defined in _1Q claim 1 - by the reaction signal • with plate to formula (III) benzonitrile derivative of formula - wherein Q represents a tertiary base and X is chlorine, bromine or iodine - (IV) ₁₅ acid derivative of formula - wherein A and B are as defined in claim 1 and Z represents a chlorine or bromine atom - is reacted.