CA1088089A - Phenylalanine oxime esters - Google Patents

Abstract

ABSTRACT
N,N-disubstituted alanine derivatives of the formula

Description

10~8()89 This invention relates to N,N-disubstituted alanine derivatives, to herbicidal compositions containing them and to a method of combating undesired plant growth. Of special interest is the ability of these alanine derivatives to exhibit selective herbicidal properties.
The present invention provides N,N-disubstituted alanine deriva-tives of the general formula:

COY

(X) ~ ! (I) \

CHCOON=CRl R2 wherein each X individually represents a hydrogen, fluorine, chlorine, bromine or iodine atom and n is an integer of from 1 to 5;
Y represents an aryl group;
Z represents an alkyl group;

Rl represents an acyl, carboxyl, alkoxycarbonyl, aminocarbonyl, mono- or di-alkylaminocarbonyl or mono or di-arylaminocarbonyl group in which the aryl groups may be unsubstituted or substituted R2 represents an alkyl, alkenyl, aryl, alkaryl, alkoxy, alkylthio or acyl group.

0~9 The preferred class of compounds have the general formula I
wherein X represents a chlorine or fluorine atom; n is 1 or 2; Y represents a phenyl and Z represents a methyl group~
Of these compounds, those of most interest are the 3,4-dichloro-, the 3-chloro-4 fluoro~, the 4-chloro- or the 4-fluoro-derivatives.
A further preferred class of compounds have the general formula I
~herein X represents a chlorine or fluorine atom; n is 1 or 2; Y represents a phenyl and Z a methyl group and Rl represents an acyl or alkoxycarbonyl group of 1 to 6 carbon atoms, an aminocarbonyl group, a mono- or dialkyl substituted aminocarbonyl group where each alkyl group contains 1 to 4 carbon atoms, a mono-arylaminocarbonyl group or a dihalophenyl aminocarbonyl group and R2 represents an alkyl group of 1 to 4 carbon atoms, an acyl group of 1 to 6 carbon atoms, a phenyl group, a benzyl group, or an alkoxy or alkylthio group of 1 to 4 carbon atoms.
It will be appreciated that many of the compounds according to the invention will exhibit geometrical and/or optical isomerism and that, therefore the individual isomers of these compounds together with isomeric mixtures thereof are included within the scope of the present invention.

-~ ~ _3_ The invention also lncludes a process for the preparation of the compounds of formula I which com-prises reacting a compound of formula:

(X~ ~COY

~ N (II) \~
CHCOOH

with a compound of formula:

HON=C (III) wherein X, Y, Z, n, Rl and R2 are as defined above. Since reaction is a condensat~on process involving the elimina-tion of water, it is preferably carried out in the presence of a dehydrative agent to absorb this by-product, an example of a suitable agent being dicyclohexylcarbodiimide.
The reaction takes place at room temperature and is preferably carried out in an inert liquid reaction medium 10l~8089 in which reactants and dehydrative agent are soluble.
A preferred solvent is methylene chloride. During the reaction dicyclohexylcarbodiimide is converted to dicyclohexylurea and removed by filtration; the remaining mixture may be worked up by conventional means.
The compounds according to the invention may be used in a manner known for herbicides, that is to say they may be used alone or together with a suitable carrier and/or surface-active agent. The invention therefore includes herbicidal compositions comprising a compound according to the invention and a carrier or a surface-active agent, or both a carrier and a surface-active agent.
The Applicant has found that the compounds are of particular interest in selectively attacking wild oats in cereal crops, particularly wheat and barley, and accordingly the invention further includes a method of combating wild oat in cereal crops by applying to the infested area a compound or composition according to the invention.
The term ~carrier~ as used herein means a solid or fluid material, which may be inorganic or organic and of synthetic or natural origin, with which the lO~W~9 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 fluid. Any of the materials usually applied in f~rmulating pesticides may be used as the 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 silicates, for example, attapulgites and vermiculites; aluminium silicates, for example, kaolinites, montmorillinites and micas; calcium carbonates; calcium sulphate; synthetic hydrated silicon oxides and synthetic calcium or aluminium silicates; elements such as for example, carbon and sulphur; natural and synthetic resins such as, for example coumarone resins, polyvinyl chloride and styrene polymers and copolymers; solid polychlor-phenols; bitumen; waxes such as for example, beeswax, paraffin wax, and chlorinated mineral waxes; and solid fertilizers, for example superphosphates.
Examples of suitable fluid carriers are water,alcohols, such as for example, ispropanol~ glycols; ketones such as for example, acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethers; aromatic hydrocarbons 108~0~9 such as for example, benzene, toluene and xylene; petroleum fractions such as for eXample, kerosine, light mineral oils; chlorinated hydro~arbons, such as for example, carbon tetrachloride, perchloroethylene, trichloroethane, including liquefied normally vaporous gaseous compounds.
Mixtures of different liquids are often suitable.
The surface-active agent may be an emulsifying agent or a dispersing agent or a wetting agent; it may be nonionic or ionic. Any of the surface-active agents usually applied in formulating herbicides or insecticides may be used. Examples of suitable surfac-active agents are the sodium or calciumsalts of polyacrylic acids and lignin sulphonicacids; the condensation products of fatty acids 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; conden-sates of these with ethylene oxide and/or propylene oxide; condensation products of fatty alcohols or alkyl phenols for example _-octylphenol or _-octylcresol, with ethylene oxide and/or propylene oxide; sulphates or sulphonates of these condensation 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~

io~ s - ~ -sodium lauryl sulphate, sodium secondary alkyl sulphates, sodium salts of sulphonated castor oil, and sodium al-kylarylsulphonates such as sodium dodecylbenzene 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 and will generally contain 0.5 to 95%w, preferably 0.5 to 75%w, of toxicant. 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 stabiliser(s) and/or other additives such as penetrants or stickers. Dusts are usually formulated as a dust concentrate having a similar composition to that of a wettable powder but without a dispersant ? and are diluted in the field with further solid carrier to give a composition usually con-taining 0.5-10%w of toxicant. Granules are usually prepared to have a size between 10 and 100 BS mesh, and may be manufactured by agglomeration or impregnation techniques.
Generally, granules will contain 0.5-25%w toxicant and 0-lO~w of additives such as stabilisers, slow-release modifiers and binding agents. Emulsifiable concentrates 10~80~9 g usually contain, in addition to the solvent and, when necessary, co-solvent, 10-50% W~V toxicant, 2-20% w/v emul-sifiers and 0-20% w~v of appropriate additives such as stabilisers, penetrants~nd corrosion inhibitors. Sus-pension concentrates are compounded so as to obtain a stable, non-sedimenting, flowable product and usually contain 10-75%w toxicant, 0.5-15%w of dispersing agents, 0.1-10%w of suspending agents such as protective colloids and thixotropic agents, 0-10%w of appropriate additives such as defoamers, corrosion inhibitors, stabilisers, penetrants and stickers, and as carrier, water or an organic liquid in which the toxicant is substantially insolublei certain organic salts may be dissolved in the carrier to assist in preventing sedimentation or as antifreeze agents for water.
Aqueous dispersions and emulsions, for example, compositions obtained by diluting a wettable powder or a concentrate according to the invention with water, also lie within the scope of the present invention.
The said emulsions ma~ be of the water-in-oil or of the oil-in-water type, and may have a thick 'mayonnaise' -like consistency.

The invention i9 illustrated in the following Examples.
EXAMPLE 1 Preparation of N-benzoyl-N-(3-chloro, 4-fluoropheny) alanine, propionyloxime ester N-benzoyl-N-(3-chloro,4-fluorophenyl)alanine (6.4 g, 0.02 mole) was dissolved in methylene chloride (60 ml) containing 2,3-pentanedione-2-monoxime (2.3 g, 0.02 mole). The reaction mixture was stirred during the addition of 4.4 g dicyclohexylcarbodiimide in methylene chloride (40 ml). The progress of the reaction was followed by thin-layer chromatography (silicon plates), the eluent beingmethylene chloride.
The reaction was completed in 8 hours. The N,N'-dicyclo-hexylurea was filtered off. After evaporation,the residue was crystallized from ethyl acetate/petroleum ether 60-80C to give the required product. m.p. 159-161C.
Yield 21%.
Analysis alculated for C21H20N204FCl: C 60.2; H 4.8;
N 6.7%
Found : C 59.9; H 5.0;
N 6.7%

A series of related compounds were prepared using the method employedin Example 1. The structure of these compounds and their physical properties are given in Table I.

. .

~D N O
o~ o~ ~ o~
Z; Z,' ~ Z Z Z
~ ~ ~ ~ ~ r~
~ 3 3 3 ~t ~ ~C, X ~: :~ ~
a~ ~. ~ L
c~ j ~ ~ ~ ~
o~ U~ U~ L~ ~ ~D
rl C~ C~ ~ {~ V
.... .... ....
c~ c~
1 ~
a~ z a~ z a~ Z
J~ U~ ~ ~ J~ U~
\ / ~ OL~ ~ Oo ~d 0~
C~ ~ X3 ~ ~ X(~ ~
ll ~ ~l O t~l ~`J O ~ ~I O
Z C~ ~ 4 VC,) ~
O
~a c~ c~ a~ ~ ~I c~
~ J` -- ~Z ~ U~

0~ l E~
~ 3 ~D J
-.~
~ ~
.' .,` ~ ~ ~ 0~~ X_~
: O~ ~ 0_~ O-C~
a) ,'`
' E~ ~ X~ :~
Z C) C~
O - ~ O - ~ O -~ ~ V C~
X
X Q, G (~1 1.~ 3 V ~
~ ~.

- 1 2 - iO8W~

1~ ~ 3 ~I
t- ~ a~ o~
Z Z Z Z
~ O
~ ~ 3 J-~C ~C
.~ .~ .~ .
O ~ ~ O~
U~
C~
.... ....
h ~ h O ~ O
~ C~
Z ~ :2 r~ J~
O ~ O
o~ ,1 ~
td ~ O ~ ~ O
C~ C~ C~ ¢ .;

~ Cr~
. _ _ ,.

. . ~
., _ ~ ~ X~
. l :~ ~C X
~ Z~ ~>
O=c~ O-~

V ~

C~ ~ ~D

iO~801 EXAMPLE 7 Tests on herb;cidal activity To evaluate their herbicidal activity, the compounds of the invention were tested using as a representative range of plants: maize, Zea mays (Mz); oat, Avena sativa (0);
rye grass, Lolium perenre (R); barnyard grass, Echinochloa crusgalli (BG); pea, Pisum sativum (P); linseed, Linum usitatissimum (L); mustard, Sinapis a _ (M); sugar beet, B _ vulgaris (SB); and tomato, Solanum lycopersicum (T).
The tests fall into two catgories, pre-emergence and post-emergence. The pre-emergence tests involved spraying a liquid formulation of the compound onto the soil in which the seeds of the plant species mentioned above had recently been sown. The post-emergence tests involved two types of test, viz., soil drench and foliar spray tests.
In the soil drench tests the soil is which seedling plants of the above species were growing, was drenched with a liquid formulation containing a compound of the invention, and in the foliar spray tests the seedling plants were sprayed with such a formulation.
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.

10~ 9 The formulations used in the tests were prepared by diluting with water solutions of the compounds in acetone containing 0.4% by weight of an alkylphenol/
ethylene oxide condensate available under the trade mark Triton X-155. In the soil spray and foliar spray tests the acetone solutions were diluted with an equal volume of water and the resulting formulations applied at two dosage levels corresponding to 5and 1 kilogrammes of active material per hectare respectively in ~ volume equivalent to 400 litres per hectare. In the soil drench tests one volume of the acetone solution was diluted to 155 volumes with water and the resulting formulation applied at one dosage level equivalent to 10 kilogrammes of active material per hectare in a volume equivalent to approximately ~,000 litres per hectare.
The herbicidal effects of the compounds were assessed visually seven days after spraying the foliage and drenching the soil and eleven days after spraying the soil, and were recorded on a 0-9 sci~le. A rating 0 indicates no effect on the treated plants, 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 cf 95%, etc.
The results of the tests are set out in Table II.

- l r) _ 10~089 _ __ . _ ~ o __ _ _ ___ ~ ~ C ~ N O
a~ ~ t- 1~ 3 1~ ~ OC) 3 ~D ~1 t- 1 N ~ ~ ~ ~ t~ 3 ~ ~ IS-h ~ ~ N ~ O ~ O ~ ~1 N O N O
u, ~ m o ~D ~ u~ o N O N O N O
a~ ~ t-- ,~ ~ 3 t-- N ~ N ~ N ~ O
P~ N ~ ~1 3 0 \~ D ~ O N O IS~ N
~ O ~ C) N O ~ O O O
_ .

m N ~1 ~1 0 ~t N N ~1 ~ O ~ O
U~ O O Ir~ O N O N O O
~ ~ ~ N 1~ N 15~ N 3 ~1 ~ ~1 IS~ 3 a~ ~ L-- ~O 3 N ~ 11'\ ~D O ~D ~
_~ ~d ~ ~ ~ ~1 ~1 ~ ~ 3 N 3 ~J ~ I_ H m o o ~ N ~D O 3 0 ~D O N O
~d O ~ ~D ~ t- ~O ~ ~ ~ ~ ~ ~

_, 1~ N I_ 1~ ~ ~D ~D ~D ~ ~D N
~1) ~i 3 0 ~1 ~1 ~ O ~C) N l~ O lr~ O
H ¦ ~

~ ~1 ~ m o o 3 1~ ~1 O
J~ V:l N O ~ O O O
`: P.. ~C ~ ~ O Lr\ ~ 3 1 ~ 1~ ~ O ~D ~D ~ ~C) H m ~ N O 3 N N
'O 1~ Ir~ ~O ~ Ir~ ~ O
V:~ O =r ~D IS~ ~D 3 O
~ O N O O O

. bO ~li ~ O U~ ~ o Lr~ ~ O L~ ~ o ~ ~ o Lr~ ~ o U~

e e ~ ~ .

Claims (5)

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

1. N,N-disubstituted alanine derivatives of the general formula:

(I) wherein each X individually represents a hydrogen, fluorine, chlorine, bromine or iodine atom and n is an integer of from 1 to 5;
Y represents an aryl group;
Z represents an alkyl group;
Rl represents an acyl, carboxyl, alkoxycarbonyl, aminocarbonyl, mono- or dialkylaminocarbonyl or mono- or di-arylaminocarbonyl group in which the aryl groups may be unsubstituted or substituted; and R2 represents an alkyl, alkenyl, aryl, aralkyl, alkoxy, alkylthio or acyl group.

2. Compounds according to claim 1 wherein X represents a chlorine or fluorine atom; n is 1 or 2; Y represents a phenyl- and Z a methyl group.

3. Compounds according to claim 1 wherein X represents a chlorine or fluorine atom; n is 1 or 2; Y represents a phenyl and Z a methyl group;
Rl represents an acyl or alkoxycarbonyl group of 1 to 6 carbon atoms, an aminocarbonyl group, a mono- or dialkyl substituted aminocarbonyl group where each alkyl group contains 1 to 4 carbon atoms, a mono-arylaminocarbonyl group or a dihalophenyl-aminocarbonyl group and R2 represents an alkyl group of 1 to 4 carbon atoms, an acyl group of 1 to 6 carbon atoms, a phenyl group, a benzyl group or an alkoxy or alkylthio group of 1 to 4 carbon atoms.

4. A process for the preparation of compounds as defined in claim 1 which comprises reacting a compound of formula::

(II) with a compound of formula:

(III) wherein X, Y, Z, n, Rl and R2 have the meanings specified in claim 1.

5. A method of combating wild oats in cereal crops by applying to the infested area an effective amount of a compound as claimed in claim 1, 2 or 3.