CA1062260A - N,n-disubstituted alanine derivatives - Google Patents

Abstract

A B S T R A C T

Wild oat herbicides of the following general formula:

Description

2;~i0 This invention relates to N,N-disubstituted alanine derivatives, to processes for their preparation, to herbicidal compositions containing them and to a method of combating undesirable plant growth.
The present invention provides N,N-disubstituted alanine deriva-tives having the general formula :-~'~ y ~ (X)n ~ N-CH-COR
,~ 3 wherein X is fluorine or chlorine and n is 1 or 2 and when n is 2 the two substituents X may be the same or different; Y is a phenyl group; and R
represents an azido group or a group of formula -NHNRlR2, in which R and R
. 10 each individually represents a hydrogen atom, an alkyl group of 1 to 4 carbon .-~ atoms, a phenyl group, a halophenyl group, an alkoxycarbonyl group of up to . 5 carbon atoms, or Rl and R2 together with the nitrogen atom to which they are .~s attached may form a pyrrolidinyl, piperidino, morpholino or 1,2,4-triazol-4-yl :~ group; and, where the derivatives are capable of forming salts, the agricul-. .
turally acceptable salts of said derivatives.
The preferred compounds according to the invention are those wherein R is an azido group or a group of formula -NHNRlR2, in which Rl and R2 . ~ .
each individually represents a hydrogen atom, a methyl group or a chlorophenyl , group.
. 20 It will be appreciated that the N,N-disubstituted alanine . derivatives according to the invention may exhibit geometrical and/or optical , isomerism. The individual isomers together with mixtures thereof are included . within the scope of the invention.
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lO~Z260 This invention also provides a process for the preparation of compounds of formula (I). Those derivatives of formula (I), wherein R
represents a substituted hydrazino group, can be prepared by reacting a : compound of formula (II):

, CO
(X)n ~ N-CH-COOH ~II) ` ~ CH;

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with a compound of formula:

Rl NH2.N \ (III) wherein X, n, Y, R1 and R2 are as defined above. The re-action is essentially a condensation process involving the elimination of water and is carried out in the presence of a suitable dehydrative agent, for example N,N'-dicyclo-hexylcarbodi-imide. The reaction takes place at ambient temperatures and is carried out in an inert reaction medium, such as methylene chloride. The dehydrative agent is con-verted to dicyclohexyl urea during the reaction and removed by filtration and the remaining reaction mixture worked up by conventional means.
Those compounds of formula (I), wherein R is an un-substituted hydrazino group can be prepared by treating a compound of formula (I), wherein R is alkoxycarbonyl, prefer-ably tert.-butoxycarbonyl, with dry hydrogen chloride; the reaction is carried out in a suitable solvent, such as ethyl acetate. Salts of N,N-disubstituted alanine derivatives of formula (I) may be prepared by reacting a compound of formula (I), wherein R represents a group of formula -NHNR1R2 with a mineral acid, e.g., hydrochloric or sulphuric acid, or with an alkyl halide, e.g., methyl or ethyl bromide or iodide, or with an alkyl sulphate, e.g., dimethyl sulphate.

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Those derivatives Or formula (I), wherein R is an azido group, are prepared by reacting sodium azide with the corresponding mixed carboxylic acid anhydride, prefer-ably prepared in situ by reacting a compound of formula (II) 5 with ethylchloroformate. The reaction solvent is con-veniently aqueous acetone.
The invention includes a herbicidal composition comprising a carrier and/or a surface-active agent and as active in-gredient at least one compound of the given general formula (I). The invention also relates to a method of eradicating or controlling weeds which comprises applying to the weeds or their habitat a herbicidally effective amount of the ; composition according to the invention or a herbicidally effective amount of the active ingredient thereof.
The term "carrier" as used herein means a material, which may be inorganic or organic and of synthetic or natural origin, with which the active compound is mixed or formulated to . . , facilitate its application to the plant, seed, soil or other object to be treated,or its storage, transport or handling. The carrier may be a solid or a liquid. Any of - the materials usually applied in formulating pesticides, herbicldes or fungicides may be used as carrier.
.
Suitable solid carriers are natural and synthetic clays and silicates,for example,natural silicas, such as diatomaceous earths; magnesium silicates, for example, talcs; magnesium aluminium :ilicates, for example, attapulgites and vermiculites;

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lO~ZZ60 aluminium silicates, for example, kaolinites, montmorillonites and micas; calcium carbonates; calcium sulphate; synthetic hydrated silicon oxides and synthetic calcium or aluminium silicates; elements, for example, carbon and sulphur;
natural and synthetic resins, for example, coumarone resins, polyvinyl chloride and styrene polymers and eopolymers; solid polychlorophenols; bitumen, waxes, for example, beeswax, paraffin wax, and chlorinated mineral waxes, and solid fertilizers, for example, superphosphates.
Suitable liquid carriers are water, alcohols, for example, isopropanol and glycols; ketones, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone;
ethers, aromatic hydrocarbons, for example, benzene, toluene and xylene; petroleum fraetions, for example, kerosine and light mineral oils; ehlorinated hydrocarbons, for example, ... . .
carbon tetraehloride, perchloroethylene and trichloroethane;
` and liquefied, normally vaporous, perchloroethylene and tri-ehloroethane; and liquefied, normally vaporous, gaseous compounds. Mixtures of different liquids are often suitable.
The surface-aetive agent may be an emulsifying agent or a dispersing agent or a wetting agent; it may be non-ionie or ionie. Any of the surfaee-aetive agents usually applied in formulating pestieides,herbieides or fungieides may be used. Examples of suitable surfaee-aetive agents are the ; 25 sodium or ealcium salts of polyacrylie acids and lignin sulphonic acids; the condensation products of fatty acids ,''' " ' ' .

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, lO~iZ260 or aliphatic amines or amides containing at least 12 carbon atoms in the molecule with ethylene oxide and/or ~: propylene oxide; fatty acid esters of glycerol, sorbitan, sucrose or pentaerythritol; condensates of these with ethylene oxide and/or propylene oxide; condensation products of fatty alcohols or alkyl phenols, for example, p-octyl-phenol or ~-octylcresol, with ethylene oxide and/or ; propylene oxide; sulphates or sulphonates of these con-densation products, alkali or alkaline earth metal salts, preferably sodium salts, of sulphuric or sulphonic acid esters containing at least 10 carbon atoms in the molecule, for example, sodium lauryl sulphate, sodium secondary alkyl sulphates, sodium salts of sulphonated castor oil, and -~ sodium alkylaryl sulphonates, such as sodium dodecyl benzene `
. ., -~ 15 sulphonate; and polymers of ethylene oxide and copolymers of ethylene oxide and propylene oxide.
~ The compositions of the invention may be formulated as - wettable powders, dusts, granules, solutions, emulsifiable ' concentrates, emulsions, suspension concentrates and aerosols.
Wettable powders are usually compounded to contain 25, 50 or 75%w of toxicant and usually contain, in addition, to solid carrier, 3-10%w of a dispersing agent and, where necessary, 0-10%w of stabilizer(s) and/or other additives, such as penetrants or stickers. Dusts are usually formulated as a dust ccncentrate having a similar composition to that of a wettable powder but without a dispersant, and are diluted lO~ZZ60 in the field with further solid carrier to give a eom-position usually containing ~-10%w Or toxieant. Granules are usually prepared to have a size between 10 and 100 BS
mesh (1.676-0.152 mm), and may be manufaetured by agglomer-ation or impregnation techniques. Generally, granules willcontain ~-25%w toxicant and 0-10%w of additives, sueh as stabilizers, slow-release modifiers and binding agents.
Emulsifiable concentrates usually eontain, in addition to the solvent and, when neeessary, eo-solvent, 10-50%w/v - lO toxieant, 2-20%w/v emulsifiers and 0-20%w/v of appropriate additives, such as stabilizers, penetrants and corrosion inhibitors. Suspension eoneentrates are eompounded so as to obtain a stable, non-sedimenting flowable product and usually contain 10-75%w toxicant, 0.5-15%w of dispersing ~ 15 agents, 0.1-10%w of suspending agents; such as protective .icolloids and thixotropic agents, 0-10%w of appropriate additives, such as defoamers, corrosion inhibitors, stabilizers, penetrants and stickers, and as carrier, water or an organic liquid in which the toxicant is sub-stantially insoluble; eertain organie solids or inorganie salts may be dissolved in the earrier to assist in prevent-ing sedimentation or as anti-freeze agents for water.
~A` Aqueous dispersions and emulsions, for example, eom-posit~ns obtained by diluting a wettable powder or a eon-

3 25 eentrate according to the invention with water, also lie .
!within the scope of the present invention. The said emulsions ~"' , .'' -'' .
~. .

1062Z6~) g may be of the water-in-oil or of the oil-in-water type, and may have a thick "mayonnaise"-like consistency.
The compositions of the invention may also contain other ingredients, for example, other compounds possessing pesticidal, herbicidal or fungicidal properties.
The invention is further illustrated by the following Examples.

EXAMPLE 1 - Preparation of 2-(N-benzoyl-N-(3-chloro-4-fluorophenyl))amino-N'-(4-chlorophenyl)-propionohydrazide , N-benzoyl-N-(3-chloro-4-fluorophenyl)alanine (6.4 g) was added to a stirred suspension of 4-chlorophenylhydrazine hydrochloride (3.6 g) in methylene chloride (50 ml) to which triethylamine (2.8 ml) had been added. The mixture l was stirred for a further 30 minutes at room temperature. ~
; Dicyclohexylcarbodi-imide (5 g) in methylene chloride ~ -(20 ml) was added and stirring continued for one hour.
N,N-dicyclohexyl urea which precipitated was filtered off and the filtrate evaporated. ~he residue was triturated with ether to give the required product as a white solid, m.p.
88-89C, yield 72%.
Analysis Calculated for C22H18Cl2FN32 C 59-2; H 4-0; N 9-4%
Found : C 59.5; H 4.1; N 9.3g ~' ~

r . ' ' .

i2Z60 EXAMPLE 2 - Preparation of 2-(N-benzoyl-N-(3-chloro-4-fluorophenyO amino-N'-(methyl)propiono-hydrazide N-benzoyl-N-(3-chloro-4-fluorophenyl)alanine (6.4 g) was dissolved in methylene chloride (70 ml) and N-methyl-hydrazine (1 ml) added. The mixture was stirred for ~ hour to give a clear solution. Dicyclohexylcarbodi-imide (5 g) was added and the precipitated urea filtered off. The methylene chloride solution was evaporated and the residue triturated with ether to give the required product, m.p.
135-138C, yield 20%.
Analysis Calculated for C17H17ClFN302: C 5 -~ Found : C 58.7; H 4.9j N 12.1%

EXAMPLE 3 - Preparation of 2-(N-benzoyl-N-(3-chloro-4-fluorophenyl))amino-N'-(tert.butoxycarbonyl)-ionohydrazide .
N-benzoyl-N-(3-chloro-4-fluorophenyl)alanine (6.4 g) was dissolved in methylene chloride (70 ml) containing . : !
, tert. butylcarbazate (2.7 g). Dicyclohexylcarbodi-imide .
(5 g) dissolved in methylene chloride (20 ml) was added at room temperature with stirring to give a clear solution.
N,N'-dicyclohexyl urea was precipitated almost immediately and the reaction mixture was left stirring for a further hour. The solid was filtered off and after evaporation of the filtrate the residue was recrystallized from petroleum i ether (60-80C) to give the required product, m.p. 78-80C, yield 84~.

~~ -, :

lO~Z260 Analysis Calculated for C21H23ClFN304: C 58-0; H 5-5; N 9.6%
Found : C 58.9; H 5.9; N 9.5%

EXAMPLE 4 - Preparation of 2-(N-benzoyl-N-(3-chloro-4-fluorophenyl))aminopropionohydrazide_ 2-~-benzoyl-N-(3-chloro-4-fluorophenyl))amino-N'-; (tert. butoxycarbonyl)propionohydrazide (11 g) was dis-solved in ethyl acetate (110 ml) and dry hydrogen chloride bubbled into the solution which was cooled in ice. The solution was left overnight and then evaporated . .
to give a resinous product. After treatment with ether the solid was washed with sodium bicarbonate solution extracted with ether which was evaporated to give the required product, m.p. 135-137C, yield 64%.
- Analysis . ., ~
Calculated for C16H15ClFN302: C 57.5; H 4.5; N 8.3%
Found : C 57.5; H 4.3, N 8.2%

EXAMPLE 5 - Preparation of 2-(N-benzoyl-N-(3-chloro-4-fluorophenyl))amino-N-morpholinopropionamide N-benzoyl-N-(3-chloro-4-fluorophenyl)alanine (6.4 g) was dissolved in methylene chloride (100 ml) and N-aminomorpho-line (2 ml) added. The mixture was stirred for ~ hour togive a clear solution. Dicyclohexylcarbodi-imide (5 g) dis-solved in methylene chloride (20 ml) was added and stirring continued for 12 hours. The precipitated urea was filtered off and the filtrate evaporated to half-volume and left ~ 25 overnight at 0C. The precipitated solid was filtered, dried .' :
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10622~0 and recrystallized from ethanol to give the required product, m.p. 205-207C, yield 93%.
Analysis Calculated for C20H21ClFN303: C 58.9; H 5.1; N 10.3%
Found : C 58.7, H 5.3; N 10.1%

EXAMPLE 6 - Preparation of 2-~benzoyl-N-(3-chloro-4-fluorophenyl))amino-N'-(trimethyl)propiono-hYdrazinium iodide 2-(N-benzoyl-N-(3-chloro-4-fluorophenyl))amino-N'-(dimethyl)propionohydrazide (1.1 g) was dissolved in ether/acetone (50 ml) and excess methyl iodide was added.
The mixture was refluxed for 6 hours and the solvent was evaporated. The residue was treated with ether/acetone (20 ml) to give pale yellow crystals of the required product, yield 60%.
Analysis -Calculated for C1gH22ClFN302: C 45.1j H 4.3; N 8.3%
Found : C 45.1; H 4.5; N 8.1%

EXA~PLE 7 - Preparation of 2-(N-benzoyl-N-(3-chloro-4-fluorophenyl))aminopropionyl azide N-benzoyl-N-(3-chloro-4-fluorophenyl)alanine (16.0 g) was stirred in water (7 ml) and sufficient acetone (30 ml) added to effect solution. The solution was cooled to 0C
and triethylamine (7 ml) in aceto~e (90 ml) was added keeping the temperature at 0C; ethyl chloroformate (6 ml) in acetone (20 ml) was added slowly and the mixture stirred for 40 minutes at 0C. Sodium azide (4.3 g) in water (15 ml) ., ` .
, .
' .
:: : ' ' ' .
was then added dropwise and the mixture stirred for one hour at 0C followed by stirring for a further 5 hours : at room temperature. The reaction mixture was poured into ice water (1 litre) and extracted with ether (2 x 250 ml).
: 5 The ethereal solution was evaporated to give the required ; product, melting point 88-91C, yield 22%.
. Analysis ~ s Calculated for C16H12ClFN402: C 55.4; H 3.5; N 16.1%
Found : C 55.1; H 3.5; N 15.8%

Following procedures similar to those given in Examples 1-7, further compounds were prepared, whose physical charac-teristics and analyses are set out in Table I.

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: , ' 10~;2;~60 , --18--EXAMPLE 19 - Demonstration of herbicidal activity ;~ 25 seeds of cultivated oats were planted in John Innes No. 1 Compost contained in 7 cm pots. When the plants had , ~ reached the 1~-2~ leaf stage the pots were sprayed with a solution of the compound to be tested in a 1:1 acetone/water mixture containing added wetter/sticker. Each compound was '~ applied at dosages of 1 kg/ha and 5 kg/ha. The pots were kept in a glasshouse at about 21C with 16 hours per day of ~- light.
Assessments were made 7 days after spraying. The percent-age depression in growth of the oats was assessed visually on a percentage scale where 100% = no growth after treatment. The results obtained are shown in the following Table II.

TABLE II
~; 15 Percentage inhibition, of growth after treatment, of ;` cultivated oats . .
.Compound Dosage kg/ha , Example No. 1 kg/ha 5 kg/ha , 7 _ 100 100 , 8 60 90 .. .

, 17 60 60 ..;

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- EXAMPLE 20 - Demonstration of herbicidal activity To further evaluate their herbicidal activity, the compounds of the invention were tested using as a represent-ative range of plants: - maize, Zea mays (MZ); rice, Oryza sativa (R), barnyard grass, Echinochloa crusgalli (BG); pea, Pisum sativum (P); linseed, Linum usitatissimum (L)-.
mustard, Sinapis alba (M) and sugar beet, Beta vulgaris (SB).
. --The tests fall into two categories, pre-emergence and post-emergence. The pre-emergence tests involved spraying a , 10 liquid formulationcf the compound onto the soil in which the seeds of the plant species mentioned above had recently been ~ sown. The post-emergence tests involved foliar spray tests in -~ which seedling plants were sprayed with a liquid formulation ~ containing a compound of the invention.
q 15 The soil used in the tests was a steam-sterilized, modified John Innes Compost mixture in which half the peat, by loose bulk, had been replaced by vermiculite.
The formulations used in the test were prepared by diluting with water solutions of the compounds in acetone containing 0.4% by weight of an alkyl phenol/ethylene oxide ~ ~ condensate available under the trade name Triton X-155. The .,'1~
acetone solutions were diluted with an equal volume of '! water and the resulting formulations applied at two dosage levels corresponding to 5 and 1 kilograms of active material :~l25 per hectare, respectively, in a volume equivalent to 400 - litres per hectare.
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ad~ k ' , ., :, - - . . ~. -10~;2260 The herbicidal effects of the compounds were assessed visually seven days after spraying the foliage and eleven days after spraying the soil, and were recorded on a 0-9 scale. A rating 0 indicates no effect on the treated plants, 5 a rating 2 indicates a reduction in fresh weight of stem and leaf of the plants of approximately 25%, a rating 5 indicates a reduction of approximately 55%, a rating 9 indicates a reduction of 95%.

~ The results of the tests are set out in Table III.
., TABLE III

Compound DosagePost-emergence Pre-emergence . Example kg/ha(foliar spray) (soil spray) - No. MZ R BG P L MSGMZ R BG P L MSB
, 1 5 00 00 0 0 0 o6 00 4 7 0 .~ 1 O O O
.~j 2 5 0 3 0 0 2 0 0 0 6 0 0 3 5 0 .; 1 O O O O
., . 7 23 67 6 3 4 02 10 3 2 1 :~ 1 3 0 0 2 0 0 ~.
: ~ . ., _ . 9 5 00 00 4 2 0 03 00 0 3 0 .~ 1 00 1 3 L~l 5 ~ 0 00 ~ 00 0 0 0 ,' . .

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Claims (4)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. N,N-disubstituted alanine derivatives having the general formula:- (I) wherein X is fluorine or chlorine and n is 1 or 2 and when n is 2 the two substituents X may be the same or different; Y is a phenyl group; and R
represents an azido group or a group of formula -NHNR1R2, in which R1 and R2 each individually represents a hydrogen atom, an alkyl group of 1 to 4 carbon atoms, a phenyl group, a halophenyl group, an alkoxycarbonyl group of up to 5 carbon atoms, or R1 and R2 together with the nitrogen atom to which they are attached may form a pyrrolidinyl, piperidino, morpholino or 1,2,4-triazol-4-yl group; and, where the derivatives are capable of forming salts, the agriculturally acceptable salts of said derivatives.

2. Compounds according to claim 1, wherein R is an azido group or a group of formula -NHNR1R2,in which R1 and R2 each individually represents a hydrogen atom, a methyl group or a chlorophenyl group.

3. A process for the preparation compounds general formula (I) given in claim 1, which comprises (a) reacting a compound of general formula (II) wherein X, n and Y have the meanings given in claim 1, with a compound of the general formula (III) wherein R1' and R2' have the meanings given in claim 1, for R1 and R2 with the proviso that both R1' and R2' may not represent hydrogen atoms, to give a compound of the general formula (I) wherein R represents a group of the general formula -NHNR1'R2';
or (b) reacting a compound of the general formula (I) wherein R
represents a group of the general formula -NHNHR1"
wherein R1" represents an alkoxycarbonyl group, with dry hydrogen chloride, to give a compound of the general formula (I) wherein R represents a group of the formula -NHNH2;
or (c) reacting a compound of the general formula (IV) wherein X, n and Y have the meanings given in claim 1, with sodium azide, to produce a compound of the general formula (I) wherein R represents an azido group;
and where required converting a compound of formula (I) where R is a -NHNR1R2 group so formed into an agriculturally acceptable salt thereof by reaction with a suitable mineral acid, alkyl halide or alkyl sulfate.

4. A method of eradicating or controlling weeds which comprises apply-ing to the weeds or to their habitat a herbicidally effective amount of a compound as claimed in claim 1 or 2.