CS207781B2 - Herbicide means and method of making the active substances - Google Patents

Abstract

Pyrrolidin-2-one derivatives of the general formula: <IMAGE> (wherein Ar represents a phenyl radical which optionally carries a substituent, or two substituents which may be the same or different, selected from halogen, C1 to 4 alkyl, C1 to 4 alkoxy, C2 to 4 alkenyloxy, C2 to 4 alkynyloxy, hydroxy, nitro, trifluoromethyl, monoalkylcarbamoyl groups in which the alkyl radical contains from 1 to 4 carbon atoms, dialkylcarbamoyl groups in which each of the alkyl radicals, which may be the same or different, contains from 1 to 4 carbon atoms, aliphatic acylamino radicals containing from 2 to 5 carbon atoms, groups of the formula Ar'-O- wherein AR' represents a phenyl radical or a heterocyclic radical with six atoms in the ring which contains, as the hetero- atom, an oxygen, sulphur or nitrogen atom, or Ar represents an aromatic heterocyclic radical with 5 or 6 atoms in the ring and contains one or two hetero-atoms selected from nitrogen, oxygen and sulphur, the hetero-atoms being the same or different when two are present, R1 represents a C1 to 4 alkyl radical, a C3 to 6 cycloalkyl radical or a phenyl radical, and R2 represents hydrogen or methyl) are new compounds useful as herbicides.

Description

The present invention relates to novel pyrrolidin-2-one derivatives, processes for their preparation and herbicidal compositions containing these compounds as active ingredients.

The active compounds according to the invention correspond to the general formula. AND,

in which

Ar represents a phenyl radical optionally substituted by 1 or 2 identical or different substituents selected from the group consisting of halogen atoms, alkyl groups of 1 to 4 carbon atoms, alkoxy groups of 1 to 4 carbon atoms and trifluoromethyl,

R 1 represents an alkyl group having 1 to 3 carbon atoms and

R2 represents a hydrogen atom or a methyl group.

All compounds of formula I contain an asymmetrically substituted carbon atom at the α-position of the Ar moiety. Thus, all of these compounds can exist in two stereoisomeric forms (optical antipodes), one of which is referred to below. D (+), has a D-configuration and is dextrorotatory (when measured under the stated conditions), and a second, denoted L (-), has an L-configuration and is left-handed. The D (+) and L (-) forms of the compounds of formula I as well as optically active or racemic mixtures of these D (+) and L (-) forms are also within the scope of the invention. In the following, racemic compounds will be denoted by (D, L).

Various pyrrolidin-2-one derivatives have been described in the literature and herbicidal properties have been described for some of these compounds.

Thus, German Patent Specification No. 1 262 277 discloses compounds useful as intermediates for the preparation of pharmaceutically acceptable substances, dyes and insecticides, which compounds correspond to the general formula

Г

N tr

z Z

(III) wherein - the individual symbols R 1, R 2 ', R 5' and RT - each represent a hydrogen atom or an alkyl, -cycloalkyl, aralkyl or aryl group containing up to 8 carbon atoms.

This very extensive formula encompasses a large number of compounds, but the examples in this German patent relate only to those compounds in which R 1 'is hydrogen, methyl, phenyl or -p-tolyl, which are not covered by the general formula shown in of the present invention.

In DOS No. 1,925,198, herbicidally active compounds corresponding to the general formula are protected

formula Her AND O in which

R 11 represents an optionally substituted alkyl, alkenyl, aralkyl, alkylenecycloalkyl, cycloalkyl or alkoxyalkyl group,

R 12 represents a crotyl, butyl, isopentenyl or isopentyl group and

R '3 has the same meaning as R' 2 or represents a hydrogen atom or R '3 together with R' 2 forms a cyclohexyl group.

This DOS mainly relates to N-cycloalkylpyrrolidin-2-ones different from the compounds of the invention. The only N-aralkyl derivatives mentioned in this DOS are N-benzyl-3-crotylpyrrolidin-2-one and N-benzyl-3-butylpyrrolidin-2-one, which compounds do not fall within the scope of the general formula given herein of the invention and for which - in the above-cited - DOS there are no herbicidal properties.

It has now been found that, in the case of 1-benzylpyrrolidin-2-one derivatives, the presence of an alkyl substituent of 1 to 3 carbon atoms on the carbon atom at the -a-position of the benzyl residue results in a significant improvement in herbicidal activity. - and that - (D, L) -1- (α-alkylbenzyl) pyrrolidin-2-ones - according to the invention - then - in general - exhibit herbicidal activity which is significantly higher than that of homologous 1-benzylpyrrolidin-2 -on.

The compounds of the invention are prepared by a process comprising the following reaction steps:

Stage 1

Reaction of γ-chloroalkanoyl chloride with an amine of formula III below according to the following reaction scheme:

Ar - CH - N - H2 - + CI - CO - CH - CH - CHCl 2 -. ; i .1 - - - г.

R1 R3 - Ra Rs

-> Ar - CH - NH - CO - CH - CH - CH - Cl +

I - I - - I

R @ 1 R @ 3 R @ 4 R @ 5 + HCl in which one of R @ 3, R @ 4 - and R @ 8 - represents a methyl group and - the remaining - of -. these symbols represent hydrogen atoms.

This reaction is carried out at a temperature between 0 and 50 ° C in an aqueous organic medium, such as a mixture of water and methylene chloride, in the presence of an inorganic base-acting as a hydrogen chloride acceptor. Said reaction is preferably carried out at a temperature between 0 and 25 ° C in the presence of sodium hydroxide.

Stage 2

Cyclization of the compound obtained in the previous reaction step according to the following reaction scheme:

Ar — CH — NH — CO — CH — CH — CH — Cl R1 R- 144 145

HCH wherein Ar, R 1, R 3, R 1, and R 5 are as defined above, and R 2 has the same meaning as in Formula I.

This reaction is carried out at a temperature between about 30 and 100 ° C in an aqueous organic medium, such as a mixture of water and methylene chloride, in the presence of an inorganic base catalyst in the form of a concentrated aqueous solution, for example sodium hydroxide.

Appropriate quaternary ammonium catalysts, such as those described in Rosz, can be used as phase transfer catalysts. Chem. 39, 1223 (1965). In practice, good results are obtained using benzyltriethylammonium chloride as a catalyst.

The D (+) or L (-) isomers of all the compounds of formula (I) may be prepared according to the general procedure described above, starting from D (+) - or (L -) - amine corresponding to the formula - III which amine is obtained by cleavage. - the corresponding (D, L (-amine) using L (- (malic acid and - D (-j -)) tartaric acid, in accordance with the procedure described in Org. Synth. Coll. -Volume-2, -page 459 - (French edition) 207781 p

β

Most (D, L) -amines of formula III are known. These compounds can be prepared by any of the following procedures A, B and C, which are known per se.

Procedure

Reaction of ammonium formate with the appropriate ketone, followed by hydrolysis of the resulting product under acidic conditions according to the following reaction scheme:

Ar — C — O + H — COONH4 -> Ar — CH — NH—

Ri Ri

H2O — CHO → Ar — CH — NH2

H + |

Rt in which Ar and Ri have the same meaning as in formula I.

This reaction, also called the Leuckardt reaction, is described in Org. React. St. 5, p. 301 (1962).

Procedure B

Reduction of oxime according to the following reaction scheme:

Ar - C = N - OH -> Ar - CH - NH 2 + H 2 O

I I

R 1 R 1 wherein Ar and R 1 are as defined above.

Either sodium in an alcohol medium (Acta Pharm. Suecica 5, p. 429, 1968) or hydrogen in the presence of Raney-nickel (Bull. Soc. Chim. France (5), 4, p. 1937).

Procedure C

Amination and reduction of ketone according to the following reaction scheme:

Ar - C - O + NH 3 + H 2 -> Ar - CH - NHb

R 1 R 1 wherein Ar and R 1 are as defined above.

The reaction is carried out in the presence of Raney-nickel according to the procedure described in Compt. Rend. Acad. Sci. 207, p. 345 (1938).

The preparation and properties of the compounds of the invention are illustrated by the following examples, which, however, are not intended to limit the scope of the invention in any way.

Example 1

Preparation of (D, L) -1- (2'-methoxy-α-methylbenzyl) pyrrolidin-2-one (Compound No. 1)

To a 2-liter three-necked round-bottomed flask equipped with a mechanical stirrer, 250 ml dropping funnel, thermometer and reflux condenser was charged 151 grams (1 mol) of o-methoxy-α-methylbenzylamine, 400 ml of methylene chloride and 1.1 mol of hydroxide sodium (pellets) in 500 ml of water. The mixture is cooled to approximately 5 ° C with vigorous stirring, and a solution of 145.5 g (1 mol) of 4-chlorobutyroyl chloride (97% purity) in 100 ml of methylene chloride is added dropwise at such a rate that the temperature of the reaction mixture is between 5 and 10 ° C.

After the addition was complete, the reaction mixture was stirred vigorously for 15 minutes before being poured into a 2 L separatory funnel and only the methylene chloride layer was isolated.

The methylene chloride solution obtained above was transferred to a 2 L 3-neck round bottom flask containing 11.4 g (0.05 mol) of benzyltriethylammonium chloride, to which 400 g (5 mol) of sodium hydroxide was added rapidly as a 50% aqueous solution. The mixture was stirred vigorously for 2 hours, refluxed at 44 DEG C. The reaction was complete by gas chromatography, and after cooling in a water bath, 400 ml of water was added to the reaction mixture, whereupon sodium chloride was added. dissolves and the phases are separated.

The reaction mixture is transferred to a 2 L separatory funnel, the methylene chloride phase is separated, the aqueous phase is extracted with 200 ml of methylene chloride and this extract is combined with the main organic phase. The organic layer was washed first with 200 ml of 1N hydrochloric acid and then three times with 200 ml of water each time. After drying and evaporation to dryness, 206 g of crude product is obtained, which is purified by distillation.

196 g of (D, L) -1- (2 &apos; -methoxy-.alpha.-methylbenzyl) pyrrolidin-2-one are obtained, having the following characteristics:

boiling point: 125 ° C / 33.3 Pa:

nD ²⁰ . 1 ^, 543.

Elementary analysis:

calculated: C 71.23%, H 7.76%, N 6.39%; Found: C 71.61%, H 7.96%, N 6.15%. Yield 89.5%.

Example 2

Following the procedure described in Example 1, using the appropriate starting materials, compounds No. 2 to 15 are obtained, the physicochemical characteristics of which are given in the following table. In this table, m.p. is the boiling point and m.p. is the melting point.

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ηγ тН СП U0 r-i со о со см см Ю со со со

·. 108 ° С / 1.3 Ра Ηθ / ο 5.45 5.58. № / ο 5,4ί 5,46

о о о 04 / О G G о О ъ ω тН д 04 / б 6 TJ <тЧ X сч γ-Ч ω fa ТК тН X см тН ω OF от-Ч Я ю б of й д LQ б ю К ю б

Elephant-corifig · Ar Ri R2 empirical formula of physical constant yield elemental analysis nLag. race (%) calculated found

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Example 3

Preparation of D (4-) -1- (2 &apos; -methoxy- N -methylbenzyl) pyrrolidin-2-one [Compound No. IA, D (-} -) Optical Isomer of Compound No. 1]

Compound No. IA was prepared as described in Example 1, using 4-chlorobutyroyl chloride and D (+) - o-methoxy-α-methylbenzylamine with an optical rotation of [α] _D ²⁰ = -j-37 ° (without solvent) as starting materials. This starting amine is obtained by cleavage of (D, L) -o-methaxx-aamethylbenzylamine as described in Org. 2ynth. Coli. Volume 2, p. 459, French edition.

The compound No. IA thus obtained has the following physical characteristics:

[.alpha.] D @ 20 = + 90 DEG (c = 0.1, anhydrous ethanol); optical purity: 90 ° / o;

nD2O = 1.5492; boiling point: 120 ° C / 6.7 Pa.

Elementary analysis:

calculated: C 71.23%, H 7.76%, N 6.39. %; Found: C 70.25%, H 7.82%, N 6.35%. He attaches

Preparation of D (-j-) -1- (α-methylbenzyl) pyrrolidin-2-one [Compound No. 2A, D (+) isomer of Compound # 2]

The procedure described in the previous example was repeated except that the benzylamine used therein was replaced with commercial D (4-) - .alpha.-methylbenzylamine having an optical rotation of [.alpha.] D @ 20 = 39 DEG (without solvent).

The compound No. 2A thus obtained has the following characteristics:

[Ref _{and D} 20 = + 19.5 ° _[C = 0.1, anhydrous ethanol), melting point: 108 ° C / 8 mmHg.

Elementary analysis:

calculated: C 76.19%, H 7.94%, N 7.41%;

Found: C 75.46%, H 8.09%, N 7.38%.

Example 1 a d 5

Herbicidal activity in pre-emergence treatment of useful plants and weeds

The appropriate number of seeds (selected by plant type and seed size) is sown in 9X9X9 cm dishes filled with light agricultural land.

The seeds are covered with a layer of approx. Mm thickness.

After moistening the soil, the trays are sprayed with a liquid preparation corresponding to a volume of 500 liters / ha and containing the appropriate dose of active ingredient.

The liquid preparation is prepared by diluting an emulsifiable concentrate having the following composition (weight%):

test drug 20% emulsifier (condensation product of nonylphenol with 17 moles of ethylene oxide) 10% solvent (xylene) 70% water to a formulation containing the active agent at the desired concentration. In the tests, the active compounds are applied in doses ranging from 1 kg to 8 kg of active compound per hectare.

The treated trays are placed in troughs to irrigate the trays in the bottom openings and maintained at room temperature and 70% relative humidity for 35 days.

After 35 days, the degree of damage was evaluated with respect to. to reference samples grown under the same conditions and treated only with an active substance-free spray.

The following crops and weeds are used for the tests:

Weeds:

Deaf oat (Avena fatua) AF Bloodthroat (Digitaria sanguinalis) D2 Hedgehog Corn leg (Echinochloa crus-galli) EC White ryegrass (Lolium multiflorum) LM (Setaria faberii) 2F Field fox (Alopecurus myosuroides) AM

Utility plants:

peanut (Arachis hypogea) AM turnip (Brassica napus) BN cotton (Gossypium barbadense) GB bean (Phaseolus vulgaris) PV soya (Glycine max) GM sunflower (Helianthus annuus) HA beet (Beta vulgaris) BV corn (Zea mays) ZM wheat (Triticum sativum) T2

The results obtained in the above tests are summarized below. Results are reported as percent damage to treated plants compared to untreated reference plants. A value of 100 means that the plant has been completely destroyed.

compound weed crop rate kg / ha AF DS EC LM SF AM AH BN GB

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Example 6

Comparative experiment

In this experiment, the herbicidal activity of the following compounds was compared in pre-emergence application at doses of 1- and 2 kg / ha.

The following are used as active substances:

l- (2 -methoxybenzyljpyrrolidin ¹ - 2-one (reference compound) and (D, L) -1- (2'-methoxy-a-methylbenzyl) pyrrol imidazolidine-2-one (Compound no. - 1).

The same test is used as in the example

5. The results obtained, evaluated as in Example 5, are shown in the following overview:

dose (kg / ha) AF DS weeds SF AM EC LM comparative substance 1 0 60 20 May 0 0 0 2 0 85 80 50 30 60 Compound No. 1 1 60 70 90 90 40 90 2 80 100 ALIGN! 100 ALIGN! 95 100 ALIGN! 100 ALIGN!

The above comparison shows that, in the case of 1-benzylpyrrolidin-2-one derivatives, the presence of a methyl substituent on the carbon atom at the α-position of the benzyl residue results in a very significant improvement in herbicidal activity.

The results obtained in Examples 5 and 6 demonstrate good herbicidal activity of the compounds of the invention.

In general, especially in pre-emergence treatment of useful plants and weeds, the compounds of the present invention exhibit good herbicidal activity against grass weeds and good selectivity to useful plants such as maize, beet, peanut, turnip, cotton, bean, soybean and sunflower. Excellent results are obtained with [D, L) -1- (2'-methoxy-α-methylbenzyl) pyrrolidin-2-one (Compound No. 1), which when pre-emergent applied at a dose of 2 kg / hectare completely it destroys bloody dew, hedgehog, leg and foxtail and shows satisfactory herbicidal activity against deaf oats and flowering rye, and is well tolerated by most experimental crop plants at the above dose.

Excellent results are also obtained with Compound No. 1A, which consists predominantly of the D (+) isomer of 1- [2'-methoxy-α-methylbenzyl) -pyrrolidin-2-one, along with a small amount; L (-) isomer of the same compound.

For herbicidal use, the doses of active compounds according to the invention can range from 0.5 to 10 kg / ha, depending on the compound used, the type of crop and the nature of the soil. Preferably, these rates range from about 1 kg / ha to 6 kg / ha.

In practice, the compounds of the present invention are rarely used alone, but most often form part of compositions generally comprising, in addition to the active ingredient of the present invention, a carrier and / or a surfactant which can be used in agriculture and which is compatible with the active ingredient.

For the purposes of the present invention, the term carrier refers to an organic or inorganic natural or synthetic material with which the active ingredient is combined to facilitate its application to the plants, to their seeds or to the soil or to the soil or to facilitate their transport or handling. The carrier may be solid (clays, natural or synthetic silicates, - resins, waxes, - solid - fertilizers, etc.) or liquid (water, alcohols, ketones, petroleum - fractions, chlorinated - hydrocarbons and liquefied - gases).

The surfactant may be an emulsifier, a dispersant or a wetting agent, and these materials may be - ionic - or non-ionic. Examples of such agents include salts of polyacrylic acids and ligninsulfonic acids, and ethylene oxide condensation products with fatty alcohols, fatty acids or fatty amines.

The compositions of the invention may be prepared in wettable form. powders, dusts, granules, solutions, emulsions, emulsifiable concentrates, suspension concentrates and aerosols.

Wettable powders are generally formulated to contain from 20 to 95% by weight of the active ingredient and, in addition to the solid carrier, usually contain 0 to 5% by weight. wetting agents - and - from 3% to 10% by weight of one or more stabilizers and / or other additives, such as penetrating agents, adhesives, anti-caking agents, coloring agents and the like. -wettable powder:

active substance (Compound No. 1) 50% calcium lignosulfonate.

(deflocculating agent) 5% anionic surfactant 1% non-caking silica 5% kaolin (filler) 39%

Granules intended for application to the soil are usually manufactured so that their particle size ranges from 0.1 to 2 mm and can be prepared by agglomeration or impregnation.

Granules generally contain from 0.5 to 25% by weight of active ingredient and from 0 to 10% by weight of other ingredients such as stabilizers, modifiers allowing slow release of the active ingredient, binders and solvents.

Emulsifiable concentrates which can be applied by spraying usually contain, in addition to the solvent and, if appropriate, cosolvents, 10 to 50% (w / v) of the active ingredient and 2 to 20 · w / v of suitable additives such as stabilizers, penetration agents , corrosion inhibitors, dyes and adhesives.

By way of example, the following emulsifiable concentrate compositions are given in which the amounts are expressed in grams per liter:

Active substance (Compound No. 1) 400 g / liter alkali metal dodecylbenzenesulfonate 24 · g / liter nonylphenol condensation product with 10 ml ethylene oxide 16 g / liter cyclohexanone 200 g / liter aromatic solvent - make up to 1 liter

Suspension concentrates, which can also be applied by spraying, are prepared so as to obtain a stable product from which the individual components do not settle. These suspension concentrates usually contain 10 to 75% by weight. active ingredients, 0.5-15% by weight of surfactants, 0.1-10% by weight of thixotropic agents, 0-10% by weight of suitable additives such as antifoams, corrosion inhibitors, stabilizers, penetration agents and adhesives, and as a water carrier · or an organic liquid in which the active substance is practically insoluble. Certain organic solids or inorganic salts may be dissolved in the carrier, which additives may help to prevent sedimentation or act as antifreeze agents.

Suitable dispersions or aqueous emulsions, for example compositions obtained by diluting wettable powders or emulsifiable concentrates according to the invention with water, are also within the scope of the invention. These emulsions may be of the "water-in-oil" or "oil-in-water" type and may also have a thick consistency, such as mayonnaise.

The compositions according to the invention may also contain other additives, for example protective colloids, adhesives or thickeners, thixotropic agents, stabilizers or complexing agents, as well as other known active substances exhibiting pesticidal properties, in particular insecticidal or fungicidal properties.

Claims (6)

SUBJECT OF THE INVENTION A herbicidal composition for use in agriculture, characterized in that it contains as an active ingredient an effective amount of at least one pyrrolidin-2-one derivative of the general formula I, in which: Ar represents a phenyl radical optionally substituted by 1 or 2 identical or different substituents selected from the group consisting of halogen atoms, alkyl groups of 1 to 4 carbon atoms, alkoxy groups of 1 to 4 carbon atoms and trifluoromethyl, R 1 represents an alkyl group having 1 to 3 carbon atoms and R2 represents a hydrogen atom or a methyl group. 2. A composition according to claim 1 which comprises as an active ingredient an optically active or racemic mixture of an optical isomer of the D (+) configuration and an optical isomer of the L (-) configuration of the compound of item 1. 3. A composition according to claim 2, characterized in that it comprises as active ingredient (D LJ-1- (2'-metho ^xy-and-: Jpyrrolidin methylbenzyl-2-one. 4. Process according to claim 1, characterized in that in the first reaction step an amine of the general formula (I) is used Ar — CH — NH2 AND Ri in which Ar and R 1 are as in 1, reacted with χ-chloroalkanoyl chloride of general formula CL — CO — CH — CH — CH — CL R 3 R 4 R 5 wherein one of R 3, R 1 and R 5 is hydrogen or methyl and the remaining of these are hydrogen, to form a compound of formula Ar — CH — NH — CO — CH — CH — CH — CL R1 R3 R4 Rs in which Ar, R 1, R 3, R 4 and R 5 are as defined above, which are then subjected to cyclization in an aqueous organic medium at a temperature of between 30 and 100 ° C in the second reaction stage, in the presence of an inorganic base and a phase transfer catalyst. 5. A process according to claim 4, characterized in that it is a phase catalyst. transfer using benzyltriethylammonium chloride. 6. A method according to claim 4, characterized by. by carrying out the first reaction step in an aqueous organic medium. in the presence of an inorganic base, at a temperature between 0 and 50 ° C.