Note: Descriptions are shown in the official language in which they were submitted.
:
65~
German Offenlegungsschrift DOS 2,433,Q67 discloses 4-phenoxy-
phenoxy-alkane-carboxylic acids and their derivatives carrying a
trif].uoromethyl group in the terminal phenyl ring.
Compounds of this type are characterized by a selectlve
herbicidal activity against grass-like weeds.
It has now been found that trifluoromethyl-phenoxyphenoxy-
alkanecarboxylic acids having additional substitutents and their
functional derivatives have an outstanding effect as selective herbicides
in crop plants.
The present invention therefore provides compounds of the
formula I
.
,
CH
0 - ~ O-C~-COR4 (1)
CF3
~R2)n
". ~ in which R2 represents identical or different substituents selected
from the group consisting of chlorine or bromine, n is 1 or 2,
and R4 is hydroxy, Cl-C8-alkoxy, Cl-C8-hydroxyalkoxy, C2-C10-alkoxy-
alkoxy, phenoxy-Cl-C4-alkoxy, chlorophenoxy-Cl-C4-alkoxy, halogeno-
`';' Cl-C4-alkoxy, C3-C6-alkenyloxy, C3-C6-alkinyloxy, C5-C8-cycloalkyloxy,
. ~ C5-C8-cycloalkenyloxy, hydrazino, amino, Cl-C4-alkylamino, di~Cl-C4)-
alkylamino, phenylamino, phenyloxy, phenylthio (the phenyl group being
optionally substituted by halogen, trifluoromethyl, me~hyl, hydroxy,
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.
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651
and/or carbo-(Cl-C2)-alkoxy)- or -Ocat, cat being the cation of
an inorganic or organic base.
In the compounds of formula I the CF3 group in the terminal benzene
nucleus is preferably in 4-position. Preferably R2 is in the 2-position
i.e. adjacent to the -0-alkanecarboxylic acid group; and R4 is
preferably (Cl-C8)-alkoxy, especially (Cl-C4)-alkoxy or allyloxy.
The compounds of formula I are prepared by reacting phenoxy-
phenols of the formula II
Cl O ~ OH II
3 (R2)n
or corresponding phenolates, optionally in the presence of an acid-binding
agent, with carboxylic acid derivatives of the formula III
CH3
X-CH-COR'4 III
in which X is halogen and R'4 is hydroxy or Cl-C8-alkoxy and, if desired,
transforming the compounds of formula I obtained into other functional
derivatives of formula I by esterification, saponification, salt-
formation, transesterification, or amidation.
In formula III X preferably represents chlorine or bromine;
preferred halogeno-propionic acids are therefore 2-bromo- or 2-
chloropropionic acid.
~ 20 The reaction is preferably carried out in organic solvents,
:
~2 - 3 -
.- ~
~ 5~ HOE 76/F 044
for example ketones such as acetone or diethyl-ketone,
carboxylic acid amides such as dimethyl formamide; sulfoxides
such asdimethyl sulfoxide; or aromatic hydrocarbons, for
example benzene or toluene. When free phenols of formula II
are used, the reaction is preferably carried out in the
presence of an alkaline compound to bind the hydrogen halide
set free, for example potassium carbonate or a tertiary organic
base such as triethylamine.
As soon as the reaction is terminated, the formed hydro~
halic salt is separated by filtration or by addition of water
and, after removal of the organic solvent (if any), the ester
or other derivative of the carboxylic acid obtained is isolated
in known manner.
The derivatives obtained can be purified in usual manner,
for example by distillation or recrystallization from an organic
solvent or from a mixture of an organic solvent and water.
The different functional derivatives of formula I can be
transformed in to one another in known manner. Carboxylic acid
esters for example can be saponified by heating with alkaline
` 20 agents, preferably aqueous bases, in the presence of lower
alcohols. The alkaline solution is then acidified whereby the
free acid separates in the form of crystals or as an oil.
The free acids of formula I, obtained by saponification or
by reaction with free halopropionic acids (R4 = OH) can be
esterified in usual manner, preferably in the presence of a
;~ catalytic amount of acid catalyst such as sulfuric acid,
toluenesulfonic acid, hydrochloric acid, a Lewis acid, for
example boron trifluoride, or an acid ion exhanger.
Suitable alcohols for the esterification are, for example,
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HOE 76/F 044
65~ -
linear or branched aliphatic alcohols having from 1 to 8 carbon
atoms, or cyclohexanol.
For the esterification the acid chlorides, which are
readily accessible, for example by xeaction of the carboxylic
acids of formula I with thionyl chloride, can be used. Reaction
of these with the aforesaid alcohols yields the corresponding
esters.
Other derivatives of formula I are obtained by reacting
the acid chlorides or esters with amines or anilines.
The starting compounds of formula II can be obtained for
example, by first preparing trifluoromethyl-phenoxyphenols
according to the process described in DT-OS 2j433,066, which are then
optionally chlorinated or brominated in known manner.
It is another object of the present invention to provide
herbicidal compositions containing the phenoxy-phenoxy-
carboxylic acid derivatives of formula I.
The herbicidal compositions according to the invention
contain 2 to 95 % of an active compound of formula I. They
can be used in the form of emulsifiable concentrates, wettable
powders, sprayable solutions, dusts, or granules, in admixture
with the usual formulation auxiliaries.
Wet~able powders are preparations that can be uniformly
dispersed in water and contain, besides the active ingredient,
a diluent or an inert substance, a wetting agent,for example
polyoxethylated alkylphenols, or polyoxethylated oleyl- or
` stearyl-amines, alkyl- or alkyl-phenyl-sulfonates, and disper-
sing agents, for example the sodium salt of lignin-sulfonic acid,
of 2,2'-dinaphthylmethane-6,6'-disulfonic acid, or sodium
. . .
~ oleylmethyl-tauride.
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Emulsifiable concentrates are obtained by dissolving the
active ingredient in an organic solvent, for example butanol,
cyclohexanone, dimethyIformamide, xylene, or aromatic hydro-
carbons having a higher boiling point, and adding a non-ionic
wetting agent (emulsifier), for example a polyoxethylated alkyl-
phenol or a polyoxethylated oleyl- or stearyl-amine.
Dusting powders are obtained by grinding the active
ingredient with finely divided, solid substances, for example
talc, natural clays such as kaolin, bentonite, pyrophillite,
or diatomaceous earths.
Spraying solutions, commercially available as aerosol
sprays, contain the active ingredient dissolved in an organic
solvent, and in addition thereto a propellant, for example a
mixture of fluorochlorohydrocarbons.
Granules can be produced by atomizing the active ing~re-
dient on to an adsorptive, granulated inert material , or by
applying concentrates of the active ingredient to the surface
of a support, for example sand, kaolinite or a granulated inert
material, with the aid of an adhesive, for example polyvinyl
20 alcohol, the sodium salt of polyacrylic acid, or mineral oils.
Alternatively, suitable active ingredients may be made into
granules, if desired in admixture with fertilizers, in the
; manner commonly used for the manufacture of granulated ferti-
; lizers.
` 25 The commercial herbicidal preparations ~ontain varying
concentrations of the active ingredients. In wettable powders
the concentration of active ingredient varies, for example,
~ from about 10 to 95 %, the remainder being the above formulation
; additives. Emulsion concentrates contain about 10 to 80 ~ of
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active ingredient, while dusting powders mostly contain 5
to 20 ~ of active ingredient and sprayable solutions about
2 to 20 %. In the case of granules, the content of active
ingredient partially depends on whether the active ingredient
is liquid or solid and on the type of granulation auxiliary
or filler used.
For application the commercial concentrates are optionally
diluted in usual manner, the wettable powder or emulsifiable
concentrate, for example with water. Dusts and granulated
formulations as well as sprayable solutions are not diluted
further with an inert substance before their application.
The amount applied varies with the external conditions, such
-~ as temperature, humidity and the like. The applied amounts
, can vary within wide limits, for example in the range of from
0.1 to 10.0 kg per hectare, preferably from 0.3 to 5 kg per
hectare.
The active compounds of the invention can be mixed with
other herbicides and soil insecticides.
-~ Alternatively, the active compounds of the invention can
be mixed with fertilizers whereby a fertilizing and simultane-
ously a herbicidal effect is obtained.
The following examples illustrate the invention.
.~
` E X A M P L E S O F P R E P A R A T I O N
..~
General methods
.
(A) 0.1 Mol of phenol (II) are dissolved in 50 ml of
methylethyl ketone, 0.11 mol of anhydrous potassium carbonate
are added and 0.11 mol of halogeno-carboxylic acid ester (III)
`~ are added dropwise. The mixture is refluxed for about 16 hours,
ice^water is added, the reaction mixture is taken up in
- 7 -
,
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methylene chloride, dried over Na2S04, the solvent is
distilled off and the crude compound of formula I is crystalli-
zed or distilled under reduced pressure.
(B) 0.1 Mol of the ester of Example 1 are dissolved in
270 ml of methanol, 24 ml of 45 % sodium hydroxide solution
are added dropwise and the whole is refluxed for 2 hours. The
solvent is then distilled off yielding the acid in the form
of the sodium salt. The free acid is obtained by adding dilute
hydrochloric acid.
(C) 80 ml of thionyl chloride are added to 0.1 mol of the
acid of Example 2 and the mixture is refluxed for 6 hours.
The excess thionyl chloride is distilled off and the acid '
;~ chloride is taken up in toluene.
(D) 0.1 Mol of sodium hydroxide dissolved in 50 ml of
water are added to 0.1 mol of an alcohol, phenol, mercaptan,
or thiophenol dissolved in 50 ml of toluene. At about 25 to
~ 40C, 0.1 mol of the acid chloride of Example 3, dissolved in
; toluene, are added dropwise. After approximately 1 hour ,
the organic solution is separated, washed with water and dried
over potassium carbonate. After distillation of the solvent,
the crude compound of formula I is crystallized or purified
by distillation.
(E) 0.1 Mol of triethylamine are added to 0.1 mol of acid
chloride (prepared according to Example 3) dissolved in 50 ml
of toluene. At 25 to 40C, 0.1 mol of an aliphatic amine or
aniline are then added dropwise. The mixture is allowed to
react for a further hour and then water is added. The toluene
phase is separated, washed with water and dried over sodium
sulfate. After distillation of the toluene, the amide or
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anilide is isolated.
In the following table there are summarized the
compounds of formula I which were prepared as described
above.
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FORMULATION EXAMPLES
E X A M P L E A: `
A wettable powder which is readily dispersible in water
is obtained by mixing
~5 parts by weight of 2-/4-(4'-trifluoromethylphenoxy)-2-
chloro-phenoxy_7-propionic acid isobutyl ester (compound
5 as active ingredient,
64 parts by weight of kaolin-containing quartz as inert sub-
stance~
10 parts by weight of the potassium salt of lignin-sulfonic
acid
1 part by weight of sodium oleylmethyl tauride as wetting'and
dispersing agent,
; and grinding the mixture obtained in a disk attrition mill.
E X A M P L E B:
A dusting powder having good herbicidal properties is
obtained by mixing
.i 10 parts by weight of 2-/4-(4'-trifluoromethylphenoxy)-2-
chloro-phenoxy7- propionic acid isobutyl ester (compound 5)
~` 20 as active ingredient and
,~i, .
90 parts by weight of talcum as inert substanae and
grinding the mixture obtained in a cross-beater mill.
,...
E X A M P L E C:
;. . ~ .
~- An emulsifiable concentrate consists of
15 parts by weight of 2-/4-(4'-trifluoromethylphenoxy)-2-
. chloro-phenoxy7-propionic acid isobutyl ester (compound 5)
~`~ as active ingredient,
75 parts by weight of cyclohexanone as solvent and
. 10 parts by weight of oxethylated nonylphenol (lOAeO) as
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~65~ HOE 76/F 044
emulsifier.
_ X A M P ~ E D:
A granulate consists, for example, of approximately
2-15 parts by weight of 2-/4-(4l-trifluoromethylphenoxy)-2-
chlorophenox~7-propionic acid isobutyl ester (compound 5)
as active ingredient and inert granulate carrier materials, for
example, attapulgite, pumice granulate and quartz sand.
E X A M P L E S O F A P P L I C A T I O N
Example I
Seeds of various weeds and crop plants were sown in pots.
The pots were treated either immediately or about 3 weeks
later when the plants had germinated and developed 3 to
4 leaves, with wettable powder formulations suspended in water.
4 Weeks after the treatment the results were evaluated
visually according to the scheme of Bolle tcf. Nachrichtenblatt
des Deutschen Pflanzenschutzdienstes 16, 1964, pages 92 to
94):
degree of damage in %
number weeds crop plants
` 1 100 O
2 97.5 to ~100 O to 2.5
3 95.0 to < 97.5 ~2.5 to 5.0
4 90.0 to < 95.0 ~5.0 to 10.0
85.0 to ~ 9o.0 ~10.0 to 15.0
,~ 6 75.0 to < 85.0 ~15.0 to 25.0
. 7 65.0 to ~ 75.0~25.0 to 35.0
8 32.5 to < 65.0>35.0 to 67.5
; 9 O to ~32.5 >67.5 to 100
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651
HOE 76/F 044
The result indicated in the following Table I shows
that at concentrations of 2.5 kg/ha and in part below
compounds 1 and 2 control important annual weeds both in
pre-emergence and post-emergence application. The listed weeds
all belong to the botanic family of graminaceae (grasses).
Important crop plants remained undamaged.Compounds 3, 5,
and 4 had a similar effect.
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Effect on weeds and crop plants in pre-emergence and post-
emergence tri~ls (preem. and postem.), dosage in kg per
hectare
.
types of I Compound no. 1 ¦ Compound no. 2
plants preem. I pos~em. I preem. poste~
. 2,5 0,6 ~ 2,5 0,6 12,5 0,6 2.5 0.
~reeds r ; i , _
Ave~a ~atua 4 6 1 7 4 7 1 8
Alopecurus
myosuroides 3 5 3 6 3 4 1 5
Setaria
lutescens 1 4 4 8 1 4 4 8
Poa tri~ialis 1 3 4 7 1 2 2 6
mul~iflorwm 1 3 3 7 2 3 1 6
Echinochlo~
crus-galli 2 4 1 6 1 3 1 6
~rop plants~~ .
sugar beet 1 1 1 1 1 1 1 1
rape 1 1 1 1 1 1 1 1
. SOybean 1 1 1 1 1 1 1 1
. pea 1 1 . 1 1 1 1 1 1
dwarf bean- 1 1 2 1 1 1 3 1
horse bean 1 1 1 1 .. 1 1 1 1
cotton 1 1 3 1 1 1 ~ 1
tomatoe 1 1 1 1 1 1 1 1
tobacco 1 1 1 1 1 1 1 1
carrot 1 1 1 1 1 1 1
: cabbage 1 1 1 1 i 1 1 1
salad 1 1 1 1 1 1 1
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E X A M P L E II
Seeds of Echinochloa crus-galli (barnyard grass) were
sown in pots sealed at the bottom. At the same time, 14 day
old rice seedlings were planted in pots of the same type.
One week later, when the barnyard grass started to germinate,
the pots were filled with water so that the water stood 1 cm
above the soil surface. Suspensions of the invention compounds
were then sprayed on the standing water. The results evaluated
4 weeks after the treatment are indicated in Table II. It
can be seen that compounds 2 and 4 kept the barnyard grass
under control without doing any noticeable harm to the rice.
Similar results were obtained with compounds 1, 3 and 5.
The following compound A (from DT-OS 24 33 067)
CF3- ~ -O- ~ -O-CH-COOCH3 A
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which was used for comparison, controlled Echinochloa almost
completely when applied in a concentration of 0.62 kg per
hectare, but it did considerable damage to rice
T a b l e II
Effect on Echinochloa and transplanted rice
,i ~
Compound , ha~~ Echinochloa . rice
-~ 2~5 , l 3
,; 2 1,25 l 2
0 62 ~ 4
. 4 1.25 2 2
. 0 62 ~ l .
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0.62 2 8
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E X A M P L E III
In a pre-emergence trial using some of the compounds
of the invention against Setaria, Echinochloa and/or Lolium
the following results were obtained:
T a b l e III
.
Effect of the compounds of the invention in pre-emergence
application.
effect on
Compound dose active Setaria Echinochloa Lolium
No. c~und.
ka/ha _ _
; 1 2.5 1 1 -
0,6 2 4 -
2 2.5 2
0.6 4 3
3 2.5 2 3
0.6 5 4
~ 4 2.5 1 2
;~ 0~6 3 4
,~ 5 2.5
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28 2.5 6
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