Note: Descriptions are shown in the official language in which they were submitted.
s~
This invention relates to novel benzyl-phenoxyalk~lecarboxylic acids
useful as herbicides. Related compounds are the subject of our copending
application Serial No. 22~,168, filed April 9, 1975, of which the present
application is a divisional.
The present invention provides benzyl-phenoxyaLkanecarboxylic acids
and the derivatives thereof corresponding to the formula
~ I
R~n)
(nl)
wherein
R is halogen, ~Cl-C4)alkyl, halo-~Cl-C4)alkyl, (Cl-C4)alkoxy, halo-(Cl-C4)alkoxy,
phenyl, -N02, -NH2 or -CN;
R' is (Cl-C4)alkyl or halogen;
n is an integer of from l to 3 with the proviso that, if R is halogen and n is
1, R occupies the ortho- or meta- position in the phenyl ring;
nl is zero or an integer of from 1 to 3;
Y is (Cl-C6)alkylene and
X is -COOH, -COO-(Cl-C8)alkyl, -CONH2, -CONH-NH2, -CN or -COO-Cat,
"Cat" being the cation of an inorganic or organic base.
In the above formula I, R is preferably halogen, especially chlorine
or bromine in the 2,4-position, nl is preferably zero, that is, the right hand
benzene ring is preferably unsubstituted, but may also be substituted by Cl
or CH3, nl in this case preferably being 1. The radical -O-Y-X is preferably
in ortho- or para-position, and especially in para-position, to the benzyl
radical. Y represents a`bove all the radical -CH(CH3)-. In the case where X
- 1 - ~
is a carboxylic ester group, this group contains prefe-rably from 1 to ~ carbon
atoms. "Cat" stands preferably for an alkali or alkaline ear-th metal ca-tion,
especially Na , K or Ca /2.
The benzylphenoxy-alkanecarboxylic acids and the derivatives thereof
corresponding to the formula I are prepared according to known rnethods J for
example by reacting benzylphenols of the formula
- C~2 - ~ OH II
(nl)
with halocarboxylic acid derivatives of the formula
Hal-Y-X III
where Hal is chlorine or bromine and X is -COO-(Cl-C8)alkyl, -CONH2, -CONH-Nll2
or -CN.
The reaction is generally carried out in an inert organic solvent
such as methanol, ethanol, benzene, petroleum ether, diethylketone, dioxan,
DMF or DMSO in the presence of an approximately stoichiometric amount of an
inorganic or organic base such as NaOH, KOH, K2CO3, Na2CO3, pyridine or
triethylamine, at temperatures of from 50 to 150C, preferably from 80 to 120C.
Subsequently, the free carboxylic acids or the salts thereof may be prepared
also in known manner from the reaction products obtained, preferably by
saponification of the esters or nitriles.
The starting products of formula II are obtained according to known
methods, for example by reaction of a correspondingly substituted benzyl
chloride with a phenol in the presence of a condensation agent such as AlC13
or ZnC13 (Ind. Eng. Chem. 28 505 (1936)). In this reaction, benzyl phenols
substituted both in o- and p-position are obtained, which may be separated
by Eractional dis~:illation.
The compoullds of formula I have an excellent selective activity
against weed grasses. In pre-emergence as well as in post-emergence treatment,
such weed grasses are destroyed at low doses, while even considerable overdoses
do not or only insigniflcantly damage broad-leaved (dicotyledonous) crop plants
and broad-leaved weeds.
Surprisingly, various crop plants from the botanic species of
grasses, for example rice, barley, wheat, sorghum, are not damaged by the
compounds of the invention at a dosage sufficient to destroy weed grasses.
The compounds may therefore be used for combating weed grasses in cereals as
wel] as in dicotyledonous crop plants such as sugar beet, leguminosae, cotton,
vegetables, cucumber species, tomatoes/ tobacco etc.
The herbicidal activi.ty is especially pronolmced against foxtail
grass, wild oat, barnyard grass, foxtail millet, and crabgrass. The compounds
may be used before or after the emergence of the plants which is not possible
with known herbicides for the selective destruction of weed grasses. Trichloro-
acetic acid, alachlor ~2-chloro-2,6-diethyl-N-(methoxymethyl)-acetanilide) and
trifluralin (N,N-di-(n-propyl)-2,6-dinitro-4-trifluoromethylaniline) for example
can be used only in pre-emergence treatment; barban (4-chloro-2-butinyl-
N-(3-chlorophenyl)-carbama~e) or chlorophenpropmethyl (2-chloro-3-(4-chloro-
phenyl)-propionic acid methyl ester) only in post-emergence treatment.
Furthermore, the concentrations required for complete destruction of the weed
grasses are considerably lower than with the cited herbicides.
The compounds of the invention may be used in usual formulations,
for example as wettable powders, emulsifiable concentrates, sprayable solutions,
dusting powders or granules.
Wettable powders are preparations which are homogeneously dispersible
in water, and which, in addition to the active ingredient and a diluent or
:iner-t substance, contain also wetting agents, for example yolyoxethylated
alkylphenols, polyoxethylated oleyl or stearyl amines, or alkyl or alkylphenyl-
sulfonates, and dispersing agents, for example the sodium salts of lignin-
sulfonic acid, 2,2'-dinaphthyl-methane-6,6'-disulfonic acid, dibutyl-
naphthalene-sulfonic acid.
Emulsifiable concentrates may be obtained by dissolving the active
ingredient in an organic solvent, for example cyclohexanone, xylene, or higher
boiling aromatics. In order to obtain a good emulsion in water, further
emulsifiers may be added.
Dusting powders are obtained by grinding the active ingredient with
finely divided solid substances, for example talcum or natural aluminates, for
example kaolin, bentonite, pyrophyllite or diatomaceuous earth.
Spraying solutions, commercially available as aerosol sprays,
contain the ac~ive ingredient dissolved in an organic solvent, and a propellant,
for example a mixture of hydrocarbon fluorides.
Granules may be obtained either by atomi~ing the active ingredient
through a nozzle onto an absorptive granulated inert materical, or by applying
a concentrate of the active ingredient by means of an adhesive, for example
polyvinyl alcohol, the sodium salt of polyacrylic acid or mineral oils, onto
the surface of a carrier, for example, sand, kaolinites or granulated inert
materials. The active substances may also be granulated by the methods used
in the preparation of fertilizer granulated material, if desired in admixture
with one or more fertilizers.
The concentration of the active substances of the present invention
in commercial herbicidal formulations may vary considerably. For example, in
wettable powders, the concentration of active ingredient may vary within the
range of from about lO % to 50 % the remaining amount consisting of the above
mentioned Formulation additives. In emulsifiable concentrates, the concentra-tion
of active ingredient may vary in the range of from about 10 % to 50 %. Dusting
powders generally contain from 5 to 20 % and spray solutions from about 3 to
20 % of active ingredient. In the case of granules, the content of active
ingredient par~ially depends on whether the active compound is liquid or solid
and on what granulating agents, fillers and other additives are used. It is
generally from 3 to 10 %.
For practical applications, the commercial concen~rates are
optionally diluted in usual manner~ for example, in the case of wettable powders
and emulsifiable concentrates, by means of water. Dust formulations, granulated
preparations and spray solutions are not diluted any more before their
application. The amount of active ingredient required for application varies
within wide limits in accordance with the external conditions, for example
temperature and moisture; generally from 0.1 to 10.0 kg/ha, preferably from
0.2 to 2.5 kg/ha, of active substances are used.
Examples of formulation:
Wettable powder consisting of
10 - 40 weight % of active substance
30 - 40 weight % of finely dispersed adsorptive silicic acid
8 " " " sodium salt of dinaphthylmethane-disulfonic acid
(TamolR NNO)
2 t, I~ 1l sodium salt of alkylnaphthalenesulfonic acid (LeonilR DB)
0.5 " " " sodium salt of oleylmethyltauride ~HostaponR T)
remainder kieselguhr.
Emulsifiable concentrate consisting of
.. . . .. _ _
20 - 50 weight % of active substance,
5 weight % of calcium salt of dodecylbenzenesulfonic acid
7 " " " nonylphenol-polyglycol ether
3 " " " oleylalcohol-polyglycol ether
remainder xylene.
Granwled material consisting of
3 - 5 weight % of active substance
2 " " " emulsifier mixture of calci~n salt of dodecylbenzenesulfonic
acid and castor oil-polyglycol ether / or ester
" " " kieselguhr or finely dispersed silicic acid
remainder quartz sand (0.3 to 1 mm 0).
The novel herbicides may also be combined with known herbicides,
for example with the following substances cited by their common names:
Urea derivatives: linuron, monolinuron, chlorotoluron,
ipuron, diuron, metoxuron, fluo-
meturon, methabenzthiazuron;
Triazine derivatives: simazine, atrazine, ametryne,
prometryne, desmetryne, methopro-
tryne, metribuzine;
Uracil derivatives: lenacil, bromacil;
Pyrazon derivatives: pyrazone;
Phenoxy-alkanecarboxylic acids: 2,4-D, MCPA, dichloroprop, meco-
prop, 2,~-DP, TBA;
Carbamic acid derivatives: barban, phenmedipham, diallate,
triallate, vernolate, benthiocarb,
Swep;
Dinitrophenol derivatives: dinitro-o-cresol, dinoseb, ~DNBP),
dinoterb, and the esters or salts
thereof;
-- 6 --
Chlorinated allphatic acids: TCA, dalapon;
Amides: diphenamide, isocarbamide;
Dipyridilium derivatives: paraquat, diquat;
Anilides: propanil, solane, monalide, alachlor,
propachlor, bentachlor;
Anilines: trifluraline, nitral:ine, oryzaline,
dinitramine;
Other active substances: dichlobenil, ioxynil, cyanazine,
pyrazone, bromofenoximJ chloro-
thalmethyl, benzoylpropethyl,
chlorophenpropmethyl, MSMA, DSMA,
nitrofen, flurenol, bentazol,
fluorodifen.
The following examples illustrate the invention and related compounds.
Examples of~ ion
E X A M P L E 1:
_ . _
2rp-~4-chlorobenzyl)-phenoxi~-propionic acid ethyl ester.
A solution of 22 g of 4-(4-chlorobenzyl)-phenol and 18.5 g of
~-bromopropionic acid ethyl ester in 100 ml of dimethyl formamide was stirred
for 2 hours at 100C together with 16 g of potassium carbonate. After cooling,
the reaction mixture was poured into 1 liter of water. ~n oil precipitated
which was separated and dried over sodium sulfate. By means of vacuum
distillation, 23.3 g of 2-rp-(4-chlorobenzyl)-phenoxi7-propionic acid ethyl
ester were obtained.
b.p.: 146 - 151C/0.1 mm Hg/nD22: 1.5527
Cl ~ CH2 { O ~ O-IH-COOC2H5
3i
E X A M P L E 2:
.
2-~-(2,4-dichlorobenzyl)-phenoxi7-propionic acid amide.
A solution of 25.3 g of 4-(2,4-dichlorobenzyl)-phenol and 15.2 g
of ~-bromopropion:i.c acid amide in 100 ml of dimethyl formamide was stirred
for 2 hours at 100C together with 16 g of potassium carbonate. After cooling,
the reaction mixture was poured into 1 liter of water. A viscous oil
precipitated which was absorbed in methylene chlorlde and washed with water.
~:Eter drying over sodium sultate, the solvent was distilled aff under reduced
pressure. The remaining colorless crystals were recrystallized from methanol.
Yield: 25.8 g; melting point 148 - 149C.
Cl ~ CH2 ~ O-CH-CON~I~
E X ~ M P L E 3:
Sodium salt of 2-~ 2,4-dichlorobenzyl)-phenox~7-propionic acid.
- 17.5 g of 2- E-(2,4-dichlorobenzyl)-phenox_7-propionic acid ethyl
ester were stirred with 100 ml of methanol and a solution of 2.5 g of caustic
soda in 100 ml of water for 3.5 hours at 50C, and then abandoned overnight
at room temperature. The solvent was distilled off under reduced pressure,
and the remaining sodium salt was dried at 60C under reduced pressure.
19.6 g of sodium salt of 2- ~ -(2,4-dichlorobenzyl)-phenoxi7-propionic acid
were obtained.
Cl ~ ~- CH2 ~ O-CII-COONa
Cl CH3
E X A M P L_E 4:
2- ~ -(2,4-dichlorohenzyl)-phenoxi~7-butyric acid ethyl ester.
-- 8 --
:llB3~ 91
A sol~t:ion of 25.3 g of ~-(2,4-dichlorobenzyl)-phenol and 15 g of
~--chlorobutyric acid ethyl ester in 100 ml of dimethyl formamide were stirred
for 2 hours at 100C with 16 g of potassium carbonate. After cooling, the
reaction mixture was poured into 1 liter of water. An oil precipitated which
was separated and dried over sodium sulfate. By vacuum distillation, 16.8 g
of 2-L~-(2,4-diclllorobenzyl)-phenoxV-butyric acid ethyl ester were obtained.
b.p.: 180 - lS3C/0.8 mm Hg/nD21: 1.5912
Cl ~ Cll2 _ ~ _ O-CH-COOC2H5
The following compounds were prepared according to the methods described
in the a~ove Examples.
o Lr~ ) ~o ~ u~ ~o oo
-~ oo ~ t~ o) t~) In ~`
D IJ~
N ~ O ~ '
a F Fa F F F ~ F
t` O ~ O O ~ o ~
o o o o ~ o o o o
P~ O O O O O O O O O
~ I~ u~ ~ o Ln o o ~ o
_ _
~ C X ~ 3: ~ ~C ~ ~
x 8 8 8 8 8 8 8 8 8
_ . ~
. ~ ~ X
~d
-rl ~ $~
~1 ~h O~,~ _ , _ _ _ _ _ _
~ I - ,
E-~
X t~ t ~ ~ to t ~ t t ~ t
~ ~ ::C 3 3 ~ U ~
~' ~ ____
h h , ~1 ~1 :C
_~ ~ N N ~
...... _ _ ,.. _ --
~C o u~l ~o 1~ ao a~ o _I N t~
- 10 -
¢~
r~ ~ ~ ~1 o ~ C~ )
n
.. .,~ C~ .. .. .. .. .. .. ..
O ~ C~l - C~l C~J ~ ~
h hP I P d~ ~ GP GP
P~ ,,, ~ ~ C~ ~ C~ ,, C~ o
.9 ~ o C"~~-1 O ~l
~ ,~ i~ c7~c~ ~ ~
P~ ` X
Co, , ' ~ o
o
.~ . ~ .... ___ _ _
o ,
~1 ~ C~ P~
rl ~ ~d
i c~ d O ~ _ _ _ _ _ _ _ _ _ _ _
~ P~ o ~ I
~ _ .. _ . . _~_ . ... __ _ _____ _ . _.. _
E~
$ P~ ~ $ X ~ ~ ~ ~ c~ c~
3~ $ 51 P:
P`l $ ~ $
$ $ ~ ~~ $ $ $ ~ ~ $
C~l C~
q 0~
~ ~ ~~ ~ ~ ~ ~ C~ ~ ~ ~
C~l C~l C`~l C~ C~
p:; l
_
~ 1 ~ u~ 1 C C~ CC~l C~l C~ C~l C~l
n ~
n ~ n ~O
n n n n
n ~D n .
n n ~ ~ ~
,i ~.. .. ..
,. ,. n ~n
c~
d~ ~ o
o ~1 ~ o
c~ o o o
o O O c~
o o ~ n
,_1 ,~
. _
I~
$~ m~
n
o o o o o o
Y ~ ~ Y ~ Y
$ -
~ ~ L,
~ o 5~ 1 ~ - o P~
~o - . . _.
~ I I ~
P~ P~ ~i $ $, P: $
~ s~
~1~
r~
.
c~
p; ~ c~
------ - -
x r~ oo ~ o ~1 ~
-- 12 --
E X A M P L, E 33:
-
2-Lp-~2,4-clichloroberl~yl~-phenoxi7-propionic acid.
17.5 g of 2- ~-(2,4-dichlorobenæyl)-phenox_7-propionic acid ethyl ester
were refluxed for 2 hours with a soliltion of 2.5 g of caustic soda in 100 ml of
methanol. After cooling, 100 ml of water were added and the mixture was acid-
ified with 2n hydrochloric acid. The propionic acid liberated precipitated in
the form of a colorless oil which, on cooling in icewater, solidified to become
a colorless wax-like mass. The yield is 15.3 g.
~ ~ } CH3
Biological Examples
E X A M P L E I:
-
Seeds of ~eeds belonglng to different botanic families were sown in
po~s and covered with earth. The same day, the earth was sprayed with wettable
powder formulations ~uspended in water of the compound of Example 5; in similar
manner, the known substance dichloropropL~-(2',4'-dichlorophenoxy)-propionic
acid7 was used as comparative agent. In a further test, both the cited sub-
stances were sprayed onto plants already emerged and having developed 2 to 3
leaves.
The results Cand also the results of all following tables~ were
evaluated according to the following scheme in degree of damage in per cent:
- 13 -
p
rlumber weeds c~op plants
_ ~_ .... ... __ _ _
100 O
2 97.5 to 100 0 to 2.5
3 95.0 ~o 97.5 2.5 to 5.0
4 90.0 to 95.0 5.0 to10.0
85.0 to go.o 10.0 to15.0
6 75.0 to 85.0 15.0 to25.0
7 65.0 to 75.0 25.0 to35.0
8 32.5 to 65.0 35.0 to67.5
9 ~ 0 to 32.5 67.5 to lO0
ln this schema number 4 is still considered an acceptable herbicidal effect tn
weeds and satisfactory preserving effect in crop plan-ts (cf. Bolle ~achrichten-
blatt des Deutschen Pflanæenschut~dienstes 16 1964, pages 92 - 94).
The results o~ t~e following Table I show~that the compound of the
invention, contrary to dichloroprop, is not or nearly not active against broad-
leaved weeds, even at a high dosage rate of 2.5 kg/ha. Its special activity is
limited to species of the family of grasses~ as demonstrated by the example
Lolium, Alopecurus and Echinochloa. Dichloroprop, Oll the other hand, shows no
actlvîty against the cited species and other grasses, which proves that the
substanres ~ the invention have a completely different activity spectrum than
the known growth herbicides of the dichloroprop type, although being of similar
chemical structllre.
Table I
Activity against ~eeds and weed grasses; pot test in a greenhouse; dosage rate:
2,5 kg/ha of A.S. (=active substance)
- 14 -
plant species pre~emergence treatment, post-emergence treatment
product of dichloroprop product of dichloroprop
Example 5 Example 5
_ _ . _ ,.. ~
A. ~eeds
~dicotyledonous
species~
Galium ;~ 2 9
Matricaria 8 5 8 ~
Ipomoea 9 2 9 3
Sinapis 9 1 8
Amaranthus 6 l 7
B. Weed grasses
(monocotyledonous
species)
Lolium 1 9 4 9
Alopecurus 2 9 2 9
Echinochloa 1
E X A M P L E II:
Seeds of w~eat, barley, Eoxtail grass (Alopecurus myosuroides~ and
wild oat ~avena fa~ua~ were sown in pots and allowed to emerge in a greenhouse;
after having developed 3 to 4 leaves they were sprayed with aqueous suspensions
o~ substances of the invention. As comparative agent, the commercially avail-
able compound chlorophenpropmethyl was used.
~ \ CH
Cl ~ ~ CH2-C~-COOCH3
15 -
The resu.lts listed in Table II sllow that 4 weeks after the treatment,
foxtail grass and wild oat were substantlally destroyed by the compounds of the
inventlon, alread~ at lo~ dosage rates o~, for examp].e, 0.62 kg/ha, whi.le the
crop plants were not or onl~ very slightly damaged. Chlorophenpropmethyl, on
the other hand, damaged wild oat only slightly at the high dosage rate of 1.25
kg~ha~ while Eoxtail grass remaîned entirely undamaged.
Table II
Pot test ~n t~e greenhouse; yost-emergence treatment dosage rates in kg/ha of A.S.
plant spec~es Chlorophenpropm~ethyl product according to
Example
1.25 0.62 . No- 5 No. 7
1.25 0.62 1.25 0.62
~ __ _ _
A. ~ed grasses
Alopecurus 9 9 1 1 1
myosuraides
Avena fatua 4 8 1 2 3 4
B. Crop plants
~eat 1 1 1 1 1
Barley _ __ 4 2 2
The compounds of Examples 18, 1~, 30 and 31 had a similar activity as those of
Examples 5 and 7.
E X A M P L E_ ~II
Barnyard grass (Echinochloa) is one of the most important weeds in rice
cultures of rice cultivating countries, both when the rice is directly sown as
well as when it i5 reared in plant nurseries and then transplanted. The two
following te~ts A and B prove that the substances of the invention are most
suitable for combating barnyard grass in rice planted according to both culti-
vating methods.
~JL~
In tes~ A, barnyard grass and rice were sown in pots simultaneously.
AEter the plants had developed 3 to ~ leaves, the in~ention compounds in the
form of aqueous suspensions were sprayed onto the plants. The result indicated
in Table III (4 weeks after the treatment~ shows that the lowest dosage rate
(0.31 kg/ha of active substance2 of all substances is sufficient ~o combat the
barnyard grass; a double dosage of substances oE the invention does not seriously
damage the rice.
In test B, 3 weeks old rice plants were transplanted into pots and
simultaneously, barnyard grass was sown. A few days later, when the barnyard
grass began to emerge, the pots were ~looded, and the invention compounds were
added to the stagnant water. The results obtained 4 weeks after the treatment
are shown in Table III.
Table III
Test in flooded pots in the greenhouse; dosage rates in kglha of A.S.
plant species products of Examples
No. 5 No. 7
0.~20.31 0.62 0.31
Test A
Simultaneous sowing of Echinochloa and rice,
Treatment: spraying after emer&ence
Echinochloa 1 3 1 2
rice 2 1 2
Test B
Sowing of Echinochloa at the time of
transplanting the rice
Treatment: Addition of the products to
the stagnant water
Echinochloa 2 2 1 4
rice _ _ i 1 _ I 1 1
E ~ ~ M P L E IV
~ _ . . . _.
In regions where there i8 a crop rotation of soybeans after corn (~or
example în wide areas of the United States of America~, volunteer corn in soy-
beans îs a serious problem. In order to test ~hether substances of the inven-
tion are suitable for combating corn in soybeans, corn and soybeans were sown
in pots and, after emergence, treated with aqueous suspensions of substances of
the inventionO (See Table IV). The results listed in Table IV show that the
compounds of the învention used for this purpose destroy the undesirable corn
plants without damaging the soybeans.
lo Table IV
Pot test in the greenhouse; post-emergence treatment dosage rate: 2,5 kg/ha of
A.S.
Plant species product of Exa~ples
No. 5 No. 19 No. 18 No. 7
_
A. ~eed grasses
Zea mays 1 ` 3 3 4
B. Crop plant
S`~ybean
E X A M P L E V:
In a further test, seeds of the barnyard grass CEchinochloa~ and fox-
tail millet CSetarla) as well as of sorghum and cotton were sown. After
emergence, the plants were sprayed with aqueous suspensions of substances of the
invention Csee Table V~.
The results show that substances of the învention, at dosage rates of
0.31 and 0.62 kg/ha, have a good to very good destructive effect on the cited
- 18 -
weed grasses withou~ da~aglng sorghum and COttOII.
Table V
Pot test in the greenhouse; post-emergence treatment dosage rates in kg/ha of A.S.
Plant species product of Rxamples
No. 5 No. 7
0.62 ~.31 0.62 0.31
~ __
A. ~eed grasses
Echinochloa 1 2 1
Setaria 1 3 1 5
B. Crop plant
Sorghum vulgare 2 1 2
.. 1 1 1
.
E X A M P L E Va:
Compounds 5 and 7 were sprayed in form of a~ueous suspensions at a
dosage rate oE 2.5 kg/ha of active substance onto a number of crop plants in the
stage of 2 to 3 leaves. The following species were not damaged: sugar beet,
common beet, spinach, cucumber, sugar melon, water melon, red clover, lucerne,
lQ peanut9 soybean, dwarf-bush bean, pea, horse bean, ~lax, carrot, celery, rape,
cabbage, tomatoe, tobacco, potatoe, cotton. This test proves that substances
of the invention may be used in dicotyledonous crop plants even at high dosage
rates without a risk for the crop plants.
_ X A M P L E Vl:
Seeds of crabgrass ~Digitarla~, wild oat (Echinochloa~ and ~oxtail
millet (Setaria~, as well as oE sorghum were sown in pots. The same day, sub-
stances oE the invention in the form of aqueous suspensions were sprayed at
- 19 -
different dosage rates on the soil surface (pre-emergence treatment). The result
indicated in Table VI shows that substances o~ the lnvention, at dosage rates oE
0.31 or 0.62 kg/ha, destroy the cited weed grasses, and that they do not damage
substantially the sorghum at the same time, nor when they are used in a high
concentratlon oE 1.25 kg/ha. The comparative agent, that i5, commer~ial alachlor
C2H5
N ~ 2 3
\,~( C-cH
C2H5
generally used in the agricultral practice for combating grasses in the pre-
emergence treatment with very good success damaged the sorghum to such an extent
that it practically cannot be used in this crop plant. The comparative agent
propachlor
1~ ~ CH~CH312
C-CH2Cl
o
also a kno~n commercial herbicide, had to be used at a much higher dosage rate;
e~en at 1.25 kg/ha, the weed grasses ~ere not completely destroyed.
E X A_M P L E VII:
In a similar test, two substances of the invention were examined ~or
their action against foxtail grass (Alopecurus2 in cereals. The result indicated
in Table VII proves that both these substances are suitable for selectively
combating foxtail grass in cereals.
- 20 -
E X A ~I P L E VIII:
In further tests, seeds o~ the weed grasses listed in Table VIII were
sown in pots, and subsequently, the earth was sprayed with an aqueous suspension
of the compound o~ Example 1. The damage values cited in Table VIII were
obtained 4 weeks after the application. 'Che data show that the subs~ances of th~
invention have a good herbicidal activity against the weed grasses used in the
test, that is, foxtail grass (Alopecurus), foxtail millet (Setaria), meadow-grass
(Poa spec.), ray-grass (Lolium) and barnyard grass.
Table VI
Pot test in the greenhouse; pre-emergence treatment; dosage rates in kg/ha of A.S.
plant specîesPropachlor Alachlor product of Example
~o. 5
1.25 1.25 0.62 0.31 1.25 0.620.31
A. ~eed grasses
Digitaria 4 1 1 1 1 1 2
Echînochloa 2 1 1 2 1 3 4
Setaria 6 3 5 7 1 1 4
B. Crop plant
Sorghum 8 7 ~ 2
- 21 -
Table UII
Pot test in the greenhous; pre-emergence treatment; dosage rates in kg/ha of A.S.
Plant species product of Example
- No. 5
1.250.62 0.31
.____
A. Weed grass
Alopecurus ~L 2 4
B. Crop plant
Autumn wheat 2 1
Autumn barley 3 1
Table VIII
Pot test in th~ greenhouse; pre-emergence treatment; dosage rate 2,5 kg/ha of A.S.
Weed grasses product of Example 1
. . _ _
Alopecurus 3
Setaria 3
Poa spec. 2
Lolium 4
Echinochloa
The compounds of Examples (62, (82, (13~, C232, C22, ~32, ~262 a~d (292 had a
similar effect.
