Note: Descriptions are shown in the official language in which they were submitted.
2~
The present invention relates to herbicidally-active
compositions comprising a phenoxy-alkanoic acid derivative
and an alanine derivative.
For many years the broad-leaved weeds which infest
cereal crops have been successfully controlled by foliar
application of plant growth regulakor herbicides, such
as phenoxy-alkanoic acid derivatives, known as hormone
weed killers.
It is known, for example from British patent speci-
fications Nos. 1,164,160 and 1,289,283 that certain
alanine derivatives have a herbicidal action upon wild
oats and furthermore, that these compounds may be used
selectively in cereal crops to control wild oats growing
alongside the cereal crops.
It would be most desirable to eradicate both broad-
leaved and grass weeds by a single post-emergence
application to a cereal crop but it has been observed
that the presence of a hormone weed killer has an antagon-
istic effect on the activity of the alanine derivative
grass weed herbicide so that the latter's effectiveness
is greatly reduced leading to much poorer control of the
grass weeds than is normally achieved by applying the two
types of herbicides separately.
It has now surprisingly been found that applying a
specific optical isomer of a phenoxy-alkanoic acid or
phenoxy-alkanoic acid derivative in combination with an
~.~
9~
alanine derivative gives a virtually unaffected activity
with respect ko grass weeds whilst maintaining the
activity against broad-leaved weeds.
The present invention provides herbicidal com-
positions comprising as active ingredients at least
one R-(-~)- isomer of a phenoxy-alkanoic acid derivative
of the general forrnula - ~ indicating the asymmetric
carbon atorn -
m ~ o ~C-C- O -Rl (I)
(R)n H
wherein R represents an alkyl group of up to 4 carbon
atoms; n is O or an integer up to 4; m is O or an integer
up to 5; Rl represents a hydrogen atom, a metal-salt
forming or an optionally alkyl-substituted ammonium ion,
or an optionally substituted alkyl, cycloalkyl~ alkenyl,
aryl or aralkyl group; and R2 represents an alkyl group
of up to 4 carbon atoms and at least one N,N-disubstituted
alanine compound of the general formula:
N / ~ (II)
\ CH-CoR3
Y CH3
wherein X represents a fluorine or chlorine atom; Y
represents a hydrogen, fluorine or chlorine atom; Q
represents an oxygen or sulphur atom and R~ represents
a group of formula -oR4,
wherein R represents a hydrogen atom, a metal-
salt forming or an optionally alkyl-substituted
ammonium ion, an optionally substituted alkyl,
cycloalkyl, alkenyl, aryl or aralkyl group;
a group of formula -SR5, in which R5 represents
an optionally substituted alkyl, cycloalkyl,
alkenyl, aryl or aralkyl group; or a group of
formula -NR6R7 or -oN=CR6R7, in which R6 and R7
each individually represents a hydrogen atom,
a hydroxy group, an optionally substituted alkyl,
alkenyl, aryl, aralkyl, heterocyclic, alkoxy,
alkylthio or amino group or R6 and R7 together
represent a polymethylene group optionally inter-
rupted by one or more hetero atoms.
The optional substituents in the alanine derivatives
of formula II are preferably one or two chlorine or
fluorine atoms, or alkyl or alkoxy groups containing up
to 4 carbon atoms. The alkyl, alkenyl, alkoxy, and alkyl-
thio groups referred to in formula II suitably contain
up to 6 carbon atoms, preferably up to 4 carbon atoms.
The aryl, aralkyl, cycloalkyl, heterocyclic and poly-
methylene groups suitably contain up to 10 carbon atoms,
2~7
preferably up to 7 carbon atoms. The hetero-atoms which
may be in the polymethylene group or in the heterocyclic
groups can be oxygen, nitrogen or sulphur atoms and
preferably one or two oxygen and/or nitrogen atoms.
Preferred compositions according to the present
invention comprise R-(-~)-phenoxy-alkanoic acid
derivatives of formula I, wherein n is 0 or 1; rn is
1, 2 or 3; R represents a methyl group; R1 represents
a hydrogen atom, a sodium or potassium ion, an
optionally alkyl-substituted ammonium ion, wherein
the alkyl groups contain up to 18 carbon atoms or an
alkyl group of up to 18 carbon atoms; and R2 represents
a methyl group.
More preferred compounds according to formula I
to be used in the compositions according to the in-
vention are potassium- and dimethylamine salts of
R-(+)-(4-chloro-2-methylphenoxy)propionic acid,
R-(+)-(2,4-dichlorophenoxy)propionic acid; and
R-(~)-(2,4,5-trichlorophenoxy)propionic acid~
Examples of N,N-disubstituted alanine compounds and
their method of synthesis can be found, for instance,
in the following German patent specifications
--6~
OLS 1 643 527; Ol,S 2 109 910; OLS 2 ~02 029;
OLS 2 349 970; OLS 2 504 319 and OI.S 2 L~60 691.
Especially preferred N~N-disubstituted alanine
compounds are those of the general formula II, wherein
X and Y each individually represents a fluorine or
chlorine atom; Q represents an oxygen atom; and R3
represents a group of formula --oR4, wherein R4 re-
presents a hydrogen atom or an alkyl group of up to
6 carbon atoms, e.g. a methyl, ethyl or isopropyl
group. When used in barley crops, preference is given
to the use of compounds wherein X represents a fluorine
atom; Y represents a chlorine atom; and R3 represents
the group -oR4, wherein R4 represents an isopropyl
group. For use in wheat preference is given to those
compounds, wherein X represents a fluorine or chlorine
atom, Y represents a chlorine atom; and R3 represents
the group -oR4, wherein R4 represents a methyl or
ethyl group.
The N,N-disubstituted alanine compounds can exist
in optically active forms, and generally speaking, the
leavo-rotatory isomer with the R-configuration is the
most active form. Thus, where it is appropriate the
N,N-disubstituted alanine compounds may be employed in
their most active optically-active forms in the com-
positions according to the present invention.
3~
Good results have been obtained with the ethyl
esters of R-(+)-(2, Ll -dichlorophenoxy)propionic acid and
R-(+)-(4-chloro-2-methylphenoxy)propionic acid,
respectively, with
N-benzoyl N-(3-chloro-4-f]uorophenyl)alanine methyl
ester (racemic mixture);
N-benzoyl-N-(3-chloro-4-fluorophenyl)alanine iso-
propyl ester (racemic mixture);
N-benzoyl-N-(3-chloro-4-fluorophenyl)alanine iso-
propyl ester (leavo-rotatory isomer); and
N-benzoyl-N-(3-chloro-4-fluorophenyl)alanine ethyl
ester (leavo-rotatory isomer).
Wild oat can be controlled in cereal crops by
application of from 0.1 to 4 kg/ha of the compositions
according to the present invention. The weight ratio of
the alanine derivative to the R-(+)-phenoxy~alkanoic
acid derivative is in the range from 1 : 0.2 to 1 : 25,
preferably 1 : 0.5 to 1 : 15.
The invention also includes a method of eradicating
or controlling both broad-leaved and grass weeds infesting
cereal crops at a locus by applying to the locus a
herbicidally effective amount of a R-(+~-isomer of a
phenoxy-alkanoic acid derivative of formula I and an
N,N-disubstituted alanlne compound of formula II.
The herbicidal compositions according to the in-
vention may be formulated in such a way as to facilitate
--8-
its application to the area to be tested and, con-
veniently, the composition includes a carrier or a
surfactant and usually a carrier and a surfactant.
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 or compounds 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 material usually applied in formulating
pesticides may be used as a carrier.
Examples of suitable solid carrier are silicates,
clays, for example, kaolinite clay, synthetic hydrate
silicon oxides, synthetic calcium silicates, elements
such as, for example, carbon and sulphur, natural and
synthetic resins, such as,for example, coumarone resins,
rosin, copal, shellac, dammar, polyvinyl chloride and
styrene polymers and copolymers, solid polychlorophenols~
bitumen, asphaltite, waxes, such as for example, beeswax,
paraffin wax, montan wax and chlorinated mineral waxes,
and solid fertilizers, for example superphosphates.
Examples of suitable fluid carriers are water, alcohols,
such as for example, isopropanol, ketones, such as for
example, acetone, methyl ethyl ketone, methyl isobutyl
ketone and cyclohexanone, ethers, aromatic hydrocarbons,
'7
_9_
such as for example, benzene and toluene, petroleum
fractions, such as for example, kerosine, chlorinated
hydrocarbons, such as for example, carbon tetra
chloride, including liquefied normally vaporous gaseous
compounds. Mixtures of different liquids are often
suitable.
The surface-active agent rnay be a wetting agent,
an emulsifying agent or a dispersing agent, it may be
non-ionic or ionic. Any of the surface-active agents
usually applied in formulating herbicides may be used.
Examples of suitable surface-active agents are the
sodium or calcium salts of polyacrylic acids, 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;
partial esters of the above fatty acids with glycerol,
sorbitan, sucrose or pentaerythritol; condensation
products of alkyl phenols, for example, p-octylphenol
or ~-octylcresol, with ethylene oxide and/or propylene
oxide; sulphates or sulphonates of these condensation
products; and alkali metal salts, preferably sodium
salts, of sulphuric acid esters or sulphinic acids
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
dodecylbenzene sulphonate.
--10--
~he co~positions of the invention may be formu~ated
as wettable powders, dusts, granules, solutions,
emulsifiable concentrates, emul.sions and pastes.
Wettable powders are usually compounded to contain
25, 50 or 75% of toxicant and usually contain, in
addition to solid carrier, 3-10% of a dispersing agent
and, where necessary, 0-10% of stabilizer(s) and/or
other additives, such as penetrants or stickers. Dusts
are usually ~ormulated 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
containing 0.5-10% of toxicant. Granules are usually
prepared to have a size between 0.15 and 1.68 mm and
may be manufactured by agglomeration or impregnation
techniques. Generally, granules will contain 0.5-25%
toxicant and 0-25% of additives, such as stabilizers,
slow-release modifiers, binding agents, etc. Emulsifiable
concentrates usually contain, in addition to the solvent
and, when necessary, co-solvent, 10-50% w~v toxicant,
2-20% w/v emulsifiers and 0-20% of appropriate additives,
such as stabilizers, penetrants and corrosion inhibitors.
Pastes are compounded so as to obtain a stable, flowable
product and usually contain 10-60% toxicant, 2-20% of
appropriate additives, and, as carrier, water or an
organic liquid in which the toxicant is substantially
insoluble.
z~
--ll--
The composltions Or the invention may contain
other ingredients, for example, protective colloids,
such as gelatin, glue, casein, gums and polyvinyl
alcohol; sodium polyphosphates; cellulose ethers,
stabilizers, such as ethylene diamine tetra-acetic
acid; other herbicides or pesticides; and stickers,
for example, non-volatile oils.
Aqueous dispersions and emulsions, for example,
compositions obtained by diluting a wettable powder
or an emulsifiable concentrate according to the in-
vention with water, also ]ie within the scope of the
present invention. The said emulsions may be of the
water-in-oil or of the oil-in-water type, and may
have a thick "mayonnaise"-like consistency.
The notation to indicate the absolute configur-
ation of the phenoxy-alkanoic acids and acid derivatives
is as stated in Experientia, Volume 12, pages 81-9l~, 1956.
The invention is further illustrated by reference
to the following Examples:-
-~2-
EXAMPLE 1 - Demonstration of the efI'ect of phenoxy-
propionic acid derivatives on the activity
of N-benzoyl-N-(3-chloro-4-f'luorophenyl)-
alanine methyl ester
The following phenoxy propionate derivatives were
formulated as 20% emulsifiable concentrates:
2,4-dichlorophenoxy propionic acid ethyl
ester (racemic mixture) (~)
R-(+)-(2,4-dichlorophenoxy)propionic acid
ethyl ester (B)
(4-chloro-2-methylphenoxy)propionic acid
ethyl ester (racemic mixture) (C)
R-(~)-(4-chloro-2-methylphenoxy)propionic
acid ethyl ester (D)
The compounds were applied as "in-tank mixtures" with
a 15% emulsifiable concentrate of N-benzoyl-N-(3-chloro-4-
fluorophenyl)alanine methyl ester (racemic mixture) (E)
to cultivated oat at the 1-1 2 leaf stage. The dosages used
for compound (E) were 0.05, 0.1 or 0.2 kg/ha in all treat-
ments. Sufficient amounts of the compounds A~ B, C and D
were added to produce mixtures with the ratios as indicated
in the Table. The compound E was also applied alone.
After spraying (single dose sprays in a total
volume of 650 l/ha) the plants were set out in random-
ized blocks in the glasshouse (there were 4 replicates
of each treatment). Phytotoxicity was assessed visually
on a 0-100 scale (where 0 = no effect and 100 = no
-13-
visible growth after spraying) 7 and 13 days after
spraying and by fresh shoot weight 20 days a~ter spraying.
The amounts of R-(+~p~noxyalkanoic acid derivatives
used in the compositions according to the invention are
lower than the amounts of the corresponding racemates
in the compositions tested f'or comparative purposes so
as to account for the higher activity of ~e R~ phenoxy
alkanoic acid derivatives in the compositions according
to the invention. The mean results obtained using 0.2
kg/ha of compound (E) are shown in Table I, the fresh
weights being expressed as % reduction in total weight
of untreated control.
-~4-
~g~
-14-
r -- ~ o ~ N ~ ~:o ~l ~o
O ~ l ~~ C~ t~l ~0 ~\ L~ ~1 ~
J ~ ~ rl rl
_ _ _
SSI-O
u~ ~ r~ ~ o~ ~ O ~
rl h co ~I ~ ~D ~ Lr~ ~r-- u~
_ ~
~ ~ . ,__ .__ ,
~ a~ ~ ~ ~ cr~ ~ a~ L~ o o t- ~
h . l Lr~ ~ ~ ~1 ~ ~I
~a~ _ _ _
rJ ~ C~ O O 0~ r~ c~ a~ o ~D
~ a~ ~ ~ o~ ~ ~ o~ ~
H I ~ ~ ~ _ ._ ___
. _ _ .. _ .
c~ O ~ O ~ u~ ~ u~
E~ ~ ~ o~
r~ rl
~ -- - - --- -
D Q)
~ ~ C~ ~ ~ CO o~ LO ~ o~ ~
~ o~ a~ o~o~ o~co a~
S.r~ _ . ..... ~.,,
rl ~ I I 3 co ~ t oc) ~ ~
3:~ ~ ~ ~ ~ ~ ~ ~ ~
,.. _
~_ ~ m ~ ~
o o ~ ~ + +
v ~ __ r~
-15-
The results given in Table I clearly indicate that
using the R-(+)-isomer of the phenoxy-propionic acid
derivatives (B~ D) causes a significantly smaller re-
duction in activity of the N,N-disubstituted alanine
compound which makes it possible to use such a mixture
in a single operation to eradicate or to control both
broad-leaved and grass weeds.
EXAMPLE 2 - Demonstration of the effect of phenoxy propionic
acid derivatives on the activity of N-benzoyl-
_ N-(3-e~or~4~1uorophenyl)alanine isopropyl ester
The compounds A, B, C and D as described in
Example 1 were applied (20% emulsifiable coneentrates)
as "in-tank" mixtures with 20% emulsifiable coneentrates
of N-benzoyl-N-(3-ehloro-4-fluorophenyl)alanine iso-
propyl ester (racemic mixture (~) and R-(-)-N~benzoyl-N-
(3-ehloro-4-fluorophenyl)alanine isopropyl ester (leavo-
rotatory isomer) (G) to eultivated oat at the 1-1~ leaf
stage. The dosages used~for eompound (F) were 0.17 O. 2
or 0.4 kg/ha and for eompound (G) 0.05~ 0.1 or 0.2 kg/ha
in all treatments. The compounds (F) and (G) were also
applied alone.
The spraying was carried out as described in
Example 1. Phytotoxicity on a 0-100 (visible) scale
was assessed 7 and 14 days after spraying and by fresh
shoot weight 15 days after spraying. The mean results
obtained using 0.4 kg/ha of compound (F) and 0.2 kg/ha
of compound (G) are given in Table II.
~6~9~
-16-
Again the results obtained indicate that using
R~ )p~noxy propionic acid derivatives (B, D) causes
a signifieantly smaller reduction in activity for the
N,N-disubstituted alanine compounds. In combination
with R-(-)-N-benzoyl-N-(3-chloro-4-fluorophenyl)alanine
isopropyl ester, virtually no reduction of activity
has been found at all.
EXAMPLE 3 - Demonstration of the effect of phenoxy propionie
aeid derivatives on the activity of R-(-)-N-
benzoyl-N-(3-ehloro-4-fluorophenyl)alanine
ethyl ester
. .
The eompounds A, B, C and D (20% emulsifiable
eoneentrates) as deseribed in the previous Examples were
applied as "in-tank" mixtures with 20% emulsifiable
eoneentrate of R-(-)-N-benzoyl-N-(3-ehloro-4-fluorophenyl)-
alanine ethyl ester (H) to eultivated oat at the 1~1
leaf stage. The eompound (H) was also applied alone.
The spraying was earried out as deseribed in
Example 1. Phytotoxieity on a 0-100 (visible) seale was
assessed 7 and 14 days after spraying and by fresh shoot
weight 15 days after spraying. The mean results ob-
tained using 0.2 kg/ha of compound (H) are given in
Table III.
Again the results obtained elearly indicate the
signifieantly reduced antagonistie effect of R-(+)-
phenoxy propionic aeids on the aetivity of N,N-di-
substituted alanine derivatives.
-17
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