SE409704B - SELECTIVE HERBICIDES - Google Patents

Description

_va1sSsn-of 2 compounds closely related compounds are considerably more effective as selective herbicides for controlling wild oats in cereal crops.

The present invention therefore relates to novel compounds of the following general formula e coc H / 6 5 - \ çH-coon CH c1 3 wherein R represents methyl or isopropyl.

The compounds may be prepared by a process which comprises reacting methyl or isopropyl N- (3-chloro-4-fluorophenyl) -2-aminopropionate with a benzoyl halide, preferably benzoyl chloride. The preparation of the compounds is illustrated in more detail in the examples below. The compounds can be used in methods known for herbicides, and the invention therefore also includes herbicidal compositions which comprise a carrier or a surfactant or both a carrier and a surfactant together with a compound according to the invention as active ingredient. The invention also comprises a method for controlling the growth of wild oats in cereal crops at a site, the method being characterized in that a selective herbicidal amount of a compound or composition according to the invention is applied to the site.

The term "selective herbicidal amount" in the present context means an amount of the compound or composition which is sufficient to produce a significant reduction in the growth of wild oats while at the same time producing an insignificant phytotoxic effect on the crop. The selective herbicidal properties of the compounds are further illustrated in the examples below. The term "carrier" in the present context means a solid or liquid material, which may be inorganic or organic and of synthetic or natural origin, with which the active compound is mixed or prepared to facilitate its application to the plants, seed, soil or other objects intended for treatment or to facilitate their storage, transport or handling.

The surfactant may be an emulsifier or a dispersant or a wetting agent; it can be nonionic or young Any carrier material or surfactant commonly used in the preparation of pesticides can be used in the compositions according to the invention and examples thereof are found e.g. in British Patents 1 289 283 and 1 164 160. i .a ~ s .....-............ s- .. _ * .. ... a. , am. _, a., m ..- QLN., v. e ... z ...- s., 7313560-0 The compositions according to the invention can be prepared as wettable powders, powders, granules, solutions, emulsifiable concentrates, emulsions, suspension concentrates and aerosols. Wettable powders are usually prepared to contain 25, 50 or 75% by weight of toxic substance and usually, in addition to solid carrier, 5-10% by weight of a dispersant and, if required, 0 to 10% by weight of stabilizer and / or or other additives such as penetrants or tackifiers. Powders are usually prepared as a powder concentrate with a composition similar to that of a wettable powder but without dispersants, and diluted in the field with additional solid carrier to give a composition which usually contains 10% to 10% by weight of toxic substance. Granules are usually prepared with a particle size of 1.676-0.152 mm and can be prepared by agglomeration or impregnation techniques. In general, the granules contain% -25% by weight of toxic substance and 0-10% by weight of additives such as stabilizers, slow release modifiers and binders. Emulsifiable concentrates usually contain, in addition to the solvent and, if necessary, co-solvents, 10-50% (w / v) toxic substance, 2-20% (w / v) emulsifiers and 0.20% ( weight / volume) of suitable additives such as stabilizers, penetrants and corrosion inhibitors.

The suspension concentrates are prepared in such a way that they contain a stable non-sedimenting, liquid product and usually contain 10-75% by weight of toxic substance, 0.5-15% by weight of dispersant, 0.1-10% by weight. suspending agents such as protective colloids and thixotropic agents, 0-10% by weight of suitable additives such as antifoams, corrosion inhibitors, stabilizers, penetrants and tackifiers and as carriers 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 prevent sedimentation or as antifreeze for water.

Aqueous dispersions and emulsions, e.g. compositions obtained by diluting a wettable powder or concentrate of the invention with water also fall within the scope of the present invention. Said emulsions may be of the water-in-oil or oil-in-water type and may have a thick, "maple-like consistency.

The compositions of the invention may also contain other ingredients, e.g. other compounds with pestioidic, especially insecticidal, acaricidal, herbicidal. and fungicidal properties.

The invention is further illustrated by the following examples, in which the temperatures refer to degrees Celsius. .. - ». + = '~ * .. ~.» - »-“.-... ~ w.-..- _ -w- -.-.- ..._ i ..- m. ...

.., - \ .... V .._ ,. ., .... ~. a ... a-vhw. i. .. _.4 .... = '. ~ ._. .. (and water (122 l); 2-chloropropionic acid (445 g) _1z13sao-o Example 1 Preparation of isopropyl-N-benzoyl-N- (5-chloro-4-fluorophenyl) -2-zminogrogionate (a) Preparation of N- (5-chloro-4-fluorophenyl) -2-aminopropionic acid 5-chloro-4-fluoroaniline (600 g) was dissolved in isopropyl alcohol (2.5 l) and sodium bicarbonate (692 g) was added to the solution, which was then heated under reflux and stir for 24 hours, the mixture was cooled to 60 ° and an additional batch of 2-chloropropionic acid (445 g) and sodium bicarbonate (692 g) were added, the mixture was then refluxed for a further 72 hours. The cooled mixture was diluted with water.25 liters) and extracted with methylene chloride (7 l). The aqueous solution was acidified with concentrated hydrochloric acid to pH 4. The precipitated crude acid was filtered off, washed with water and dried. (b) Preparation of isopropyl-N- (5-chloro-4-fluorophenyl + 2-amino-chlorogionate N- (3-chloro-4-fluorophenyl) -2-aminopropionic acid (725 g) prepared as under (a)) was dissolved in dry isopropyl alcohol (2.5 L). The solution was saturated with hydrogen chloride gas and refluxed for 4 hours. The volatile components were then distilled off and the residue was washed with an ice-cold aqueous solution of sodium bicarbonate to give the desired ester. (c) Benzylation of isopropyl-N- (5-chloro-4-fluorophenyl) -2-amino-chlorogionate Isopropyl-N- (5-chloro-4-fluorophenyl) -2-aminopropionate (840 3, prepared as under (b)) in dry toluene (2 L) was treated with benzoyl chloride (562 g) and the mixture was refluxed for 5 hours. The solvent and excess benzoyl chloride were distilled off and the residue was recrystallized from benzene to give isopropyl-N-benzoyl-N- (5-chloro-4-fluorophenyl) -2-aminopropionate, m.p. 65-65 °.

Calculated for C 19 H 19 NO 5 ClF: G 62.7; H 5.2; N 5.9% Found: C 62.6; H 5.4; N 3.6% Example II Preparation of methyl-N-benzoyl-N- (5-chloro-4-fluorophenyl) -2-agino-Qrogionate (a) Preparation of methyl N- (5-chloro-4-fluorophenyl) -2-Aminopropio-Nate N- (5-chloro-4-fluorophenyl) -2-aminopropionic acid (5.0 5) was dissolved in dry methanol (50 ml). The solution was saturated with hydrogen chloride gas and reflux. .l_n ...._ ~ «-4 ..._....-...., _.,. Boiled for 4 hours. The volatile components were then distilled off and the residue was washed with an ice-cold aqueous solution of sodium bicarbonate to give the desired ester. (b) Benzoylation of methyl N- (5-chloro-4-fluorophenyl) -2-aminopropionate Methyl N- (5-chloro-4-fluorophenyl) -2-aminopropionate (2.52 g, prepared as in (a)) in dry toluene (50 ml) was treated with benzoyl chloride (1545 g) and the mixture was refluxed for 5 hours. The solvent and excess benzoyl chloride were distilled off and the residue. was recrystallized from benzene to give methyl N-benzoyl-N- (5-chloro-4-fluorophenyl) -2-aminopropionate, m.p. 77-9 °.

Calcd for C 17 H 15 NO 5 ClF: C 60.8; H 4.5; N 4.2% Found: C 61.2; H 4.6; N 4,1% Exemgel III Selective herbicidal properties (wild oats in barley) of isopropyl-N-benzoyl-N- (5-chloro-4-fluorophenyl) -2-aminopropionate (compound 1) 25 seeds of barley (var. Imber) or 50 seeds of wild oats (Avena fatua) were planted in John Innes No. 1 compost in 7 cm pots. When the plants had reached the 1% -2% leaf stage, the pots were sprayed with a solution of the test compound in a 1: 1 mixture of acetone and water containing wetting agent and tackifier as an additive. The barley plants were treated in dosages of É 10-0 0.6 kg / ha and the wild oats in dosages of 2.0-0.15 kg / ha. Each dose was repeated 4 times. The pots were stored in a greenhouse at about 21 ° with 16 hours of daylight.

Evaluation of the plants was done 10-14 days after spraying. The grain was cut at the surface of the soil and the weight of the plant was expressed as a percentage of the weight of untreated grain. The percentage reduction in the growth of wild oats was evaluated visually. The values obtained were then used to calculate the growth inhibition doses and the dose which gave a 10% reduction in barley (Glblo) was compared with the dose which gave a 90% reduction in wild oats (GID 90). The selectivity factor for the compound in question is then calculated by the formula GID10 barley GIDQO wild oats. compound P); ethyl N-benzoyl-N- (4-fluorophenyl) -2-aminopropionate (Compound Q); ethyl N-benzoyl-N- (5-chloro-4-fluorophenyl) -2-aminopropionate (pre--Mf- fl-. vv- xm- -.- L »-. - _ .Aw- annu-m . vrå-M ... »øæv Um. .U- un., s. =« ....- »- us» ~.-.- s..a .. »n- fl _.-- .. lz.f.wu. fl. se. wanna .. ... ~ .... ». t_ ...__. .... ana .... ~ ... f« - ~ .. 'för calculation of the growth inhibition dosages and the dosage obtained by L 1313560-o ning R) and n-propyl-N-benzoyl-N- (5-chloro-4-fluorophenyl) -aminopropionate (compound S).

Table I '/ COC6H5 N \\\\ 0HCOOZ CH; , EX Compound GID10 GlDâQ Selective Example Test X Y Z barley will change factor 1 A F Cl CH (CH3) 2 5.7 0.75 4.9 2 - A 01 Gl C2H5 0.028 1.00 0.05 Q. AFH C2H5 0.50 1.00 0.50 SAF, Cl CH2CH2CH5 0.02 0.85 _ 0.024 RBF Cl C2H5 0.014 2.2 0.10 PB Cl Cl CQH5 0.085 5.7 0.02 It is clear from the results in Table I that The compound of the invention is a considerably more selective herbicide for wild oats than its immediate relatives. The results marked with an "A" were all obtained in experiments, performed simultaneously, and are thus strictly comparable with each other. The results marked with "B" were obtained in another series of experiments, so a possible comparison with the "A" results should be assessed accordingly.

Example gel Iv, Selective herbicidal properties of methyl N-benzoyl-N- (5-chloro-4-fluorophenyl) -2-aminopropionate (Compound 2) Seeds of barley or wheat or 50 seeds of wild oats (Avena spp) was planted in John Innes nr l compost in 7 about pots. When the plants had reached the 1% Zaeblad stage, the pots were sprayed with a solution of the compound § in a 1: 1 mixture of acetone and water containing added wetting agent / _ / tackifier. The barley and wheat plants were treated in doses of 10-0.6 I kg / ha and the wild oats in doses of 2.0-0.15 kg / ha. Each dose was repeated 4 times. The pots were stored in a greenhouse at about 2 ° with 16 hours of daylight. '_ _ _ Evaluation of the plants was done 10-14 days after spraying. É The plants were cut at the soil surface and the plant weight was expressed in% of the weight 1 of the untreated plant. The percentage reduction in the growth of wild oats was assessed visually. The values obtained were then used to give a 10% reduction in the growth of barley and wheat (Glblo), compared with c now ... an ... ... ........_._._ .. ..l .... e _ «.. ~ -.......-..-...__ ..,. ~ .ß-.wU- m .... nu..a- ........... z <.._ «n-.::_eaaw wei-ne, -» e .. a, 7 7313560-0 with the dosage which gave a 90% minekninš of the growth of wild oats (GID9O). The selectivity factor for the compound in question is then calculated by the formula GID10 barley, wheat ÜIÜQO viïd fi avre. The results of this experiment are given in the table below, in which the aminopropionate (Compound R) and ethyl N-benzoyl-N- (5,4-dichlorophenyl) -2-aminopropionate (Compound P) obtained are given for comparison purposes.

Table II: 0 G11; selectivity- einm selectivity- Association will oats wheat factor (wheat) barley factor (barley) 2 0.57 5.06 8.3 2.04. 5.5 R 0.52 2.55 4.5 0.54 1.0 ~ P 2.41 - - 2.9e 1.2 From the results in Table II it appears that the methyl ester according to the invention shows a slightly higher activity and greater selectivity towards: wild oats than corresponding ethyl analogues.

Claims (1)

7313560-0 Patent claims The compounds methyl-N-benzoyl-N- (5-chloro-4-fluorophenyl) -2-aminopropionate and isopropyl-N-benzoyl-N- (β-chloro-fluorophenyl) -2-aminopro pionate for use as selective herbicides. MENTIONED PUBLICATIONS: