Note: Descriptions are shown in the official language in which they were submitted.
Z~882
The present invention rela-tes to new substituted
benzamides oE the formula
O-C-NI-I-CH -R
CH3~CH3
wherein R represents a vinyl or ethinyl radical. The inven-
tion also relates to the use of such compounds as herbicides
per se, or in combination with other pesticidal or herbicidal
substances. Preferably, they are used in the ~orm of liquid
or solid mixtures, or liquid or solid solutions.
A number of substances of the benzam:ide series are
already known which have herbicidal properties. U.S. patents
3,534,098 and 3,640,699 describe 3,5-disubstituted 1,1-
dimethylpropinyl henzamides and their use as herbicides. As
substituents in the 3,5 positions, F,Cl,Br or the methyl
radical are mentioned. U.S. patent 3,551,484 describes
N-(l,l-dimethyl-propenyl) -3,5-disubstituted benzamide 5 and
their herbicidal properties.
From this series, the 3,5-dichloro-N-(l,l-dimethyl~
propinyl)-benzamide, which is sold commercially under the
trademark "KERB", has achie~ed particular importance; this
compound has, however, in its phytotoxic activity, the
drawback of low tolerance to a number of useful plants.
In J. Agr. Food Chem., Vol. 19, No. 3, 1971, p. 417-
21, the relationships between structure and herbiciclal
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activity are studied on a number of benzamides, which have
a similar skructure to 3,5-dichloro-N-(1,1-dlmethylpropinyl)-
benzamide. In this article it is shown that di-substikution
at the aromatic radical leads to the best results. 11 is
main-tained that 3,5-dimethyl substitution is not superior
; to 3,5-dichloro subs-titution. Taking as an example the
3,5-dichloro substitution,it is stated moreover that the
activity increases from propylamide through the allylamide
to propargylamide, the activity being further strengthened
by dimethyl substitution at the first carbon atom of the
alkyl radical.
It is the object of the present invention to provide
a herbicide having a selective phytotoxic effect which, while
having a high tolerance to useful plants, has a high efective-
ness against undesirable plants in agricultural and horti-
cultural areas, or any other areas under cultivation.
It has been found, according to the invention, that
the desirable effect is achieved by benzamide compounds, which
do not have 3,5-dichloro substitution, but 3,5-climethyl
substitution, and which do not exhibit dimethyl substitution
at the first carbon atom of the alkyl radical. These two
differences in the structure of the molecule should, in
accordance with the cited studies, lead to a decxease in
herbicidal effectiveness.
In view of the above-mentioned studies it could
not be expected and is therefore surprising that tha compounds
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of the invention are of such high herbicidal potency, while
having at the same time an improved selecti~:ity, that is to
say, having a high tolerance to useful plant~. Thus, the
compounds according to -the invention are equal to or surpass
the known 3,5-dichloro-N-(dimethylpropinyl)--benzamide in
their herbicidal effectiveness.
The extreme importance of these new agents for
agricultural purposes will be demons-trated by the following
example of winter rape:
Winter rape is sown in the fall after other
important ~gricultural plants, e.g. grains, are sown. It
is a known fact that a considerable amount of grain is lost
before the harvest and during the threshing which results
in individual grains dropping to the soil. These grains
germinate after the following cultiva-tion as so-called
l'off-grade grain" or "scatterings". As these grains grow,
they constitute a considerable rival for the wintex rape,
since they take up some of the available water J nutrients,
light and space. They cannot be tolerated because they lead
to a high reduction in yield.
It is therefore of great significance to modern
agriculture to provide a herbicide which combats the off-
grade grains and the various weeds, while saving the useful
plants of the cultivation.
The herbicidal effect oE the compounds according
to the invention extends, first of all, to highly yield-
8~
reducing weeds, such as e.g. wild oats, foxtail; meadowgcass (e.g., hair grass, thyrsus grass, brome grass and
poa spec;es), true grasses, (e.g., wind grass, rye
grass, dogstail), species of millet grasses (e.g., chick
corn, bristle millet) and to off-grade grains in general
(for example, wheat, barley, rye, oats) and important
dicotyledonous weeds (such as, e.g., knot plants,
speedwell, deadnettle, chickweed and others).
Examples of other agricultural and horticultural
cultivations in which the agents according to the
- invention are used for selective effect are: rape,
mustard, alfalfa, potatoes, vegetable cabbages (e.g.,
white cabbage, red cabbage, cauliflower), radishes,
lettuce, endives, sunflowers, ar-tichokes, and ornamental
shrubs from the family of compositae (e.g., -~
chrysanthemums, asters and dahlias).
The preparation of the new compounds according to
the invention may be carried out in a manner known per
se, by starting with 3,5-dimethyl benzoic acid, which is
commercially available. This compound is then converted
into the acid chloride by treatment with thionyl
chloride or phosphorus pentachloride, preferably in the
presence of an inert solvent (e.g., benzene, toluene,
petrol ether, or chloroform), at temperatures of 20C
to 120C. In the next step of the reaction, the acid
chloride is reacted with allylamine or propargylamine at
temperatures from 20C to 120C to form the
corresponding amide. In order to neutralize the
hydrochloric acid formed in the reaction,
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an excess amount of amine is added, or one operates in the
presence oE an auxiliary base (e.g., triethylamine or
pyridine).
As previously m2ntioned, the compounds according
to the invention may be used ~ se or in mixture In
general, they are used in mixtures with solid or liquid
diluents or in solutions with solid or li~uid solvents,
with an amount of effective agent from 0.01 to 95% by
weight.
The mixtures or solutions, respectively, are generally
in the form of emulsion concentrates, pastes, spray powders,
granulates, or microcapsules.
Emulsion concentrates as a rule contain 10 - 60
preferably 15 - 40%, by weight of the effective agent,
2 - 25% by weight of dispersion auxiliaries and organic
solvents and/or water. Spraying powders usually contain
10 - 80%, preferably 15 - 70%, by weight of the ~ffective
agent, 1 - 10% by weight of dispersion auxiliaries~ and
10 - 89% by weight of inert ingredients. Granulates and
microcapsules contain in addition to inext ingredients,
binders and/or coatings, and 1 - 10%, preEerably 5 10~,
by weight of the active agent.
As dispersing agents used in accordance with the
invention, alkyl and aryl sulfonates, methyl cellulo~e,
polymeric sulfonic acids and their salts, polyalcohols,
.Z9~Z
fatty acid esters, fatty alcohol ethers and fatty
amines are suitable. Organic solvents suitabl~ for use
are, e.g., alcohols, such a~ ethanol, butanol, climethyl-
formamide (D~F), dimethylsulfoxide tDMSO), N-m~!thylpyr-
rolidone and aromatics, such as toluene and xylene.
As inert ingredients, the following, e.g., are
suitable: kaolin, china-clay, talcum, calcium carbonate,
highly dispersed silica, silicon gels, kieselguhr,diatomaceous
earth, pumice,brick chips, corn husks and thickening agents
such as starch and carboxy-methylcellulose. Suitable hinders
include, e.g., magnesium sulfate, gypsum and gum arabic.
Suitable formulations of herbicides with agents
according to the invention include, e.g~, the following:
1. Emulsion concentrate:
20% by weight of effective agent
50% by weight of isopropanol
20~ by weight of xYlene
10% by weight of extenders and binders of the firm
Atlas-Chemie, Essen, West Germany, sold under the
trademark "Atplus 526."
2. Spraying powders:
20% by weight of effective agent
44% by weight of China-clay
16% by weight of highly dispersed silica
15% by weight of lignin sulfonate ~Cellulose pitch)
5% by weight of sodium-alkylnaphthalene ~ulfonate-
formaldehyde-condensate sold under the trademark
"Atlox 4862."
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In general, the efect.ive agents are used in
amounts o~ O.S - 8 kg/ha and, preferably, 2 - 4 kg/ha.
The application as herbicides may be carried out on
the plants (post-emergence process) or ~y direGt
application to a surface of the soll free of vegetat.ion
(pre-emergence or pre-seeding process). Better
herbicidal effects are obatined by application o the
herbicides to the soil, preferably before sowing of
cult.ivated plants, with working of the agents into the
10 uppermost layers of the so.il with mechanical means so as
to form flat strata in the soil.
In the following, the preparation of the herbicides
according to the invention will be more fully
illustrated by a number of examples, which will also
demonstrate the herbicidal properties of the products
per se and in comparison with known herbicides. It
should, however, be understood that these examples are
given by way of illustration only and not by limitation.
EXAMPLE 1
Preparation of 3,5-dimethyl-benzallylamide:
Step .l:
Into a three-neck flask with stirrer and refulx
cooler, 170 g (1.13 mol) of 3,5-dimethyl benzoic acid are
introduced together with 1,500 g toluene and about 2 g
N,N-dimethylformamide, and heated to abou~ 70C~ 202 g
(1.7 mol) of thionyl chloride are added dropwise and heated
.
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under reflux, until the gas development has ceased. Then,
the excess amount of thionyl chloride and the solvent axe
withdrawn and the residue is d.istilled in vacuo. Obtained
are 182.7 g of 3,5-dimethyl-benzoic acid chloride, which
is 95.9% of the theoretical amount.
Step 2:
74 g (1.3 mol) of allylamine and 131 g (1.3 mol)
of triethylamine are introduced, together with l,800 g of
toluene, into a reaction flask and heated to about 70C.
To this, 182 g (1.08 mol) of 3,5-dimethyl-benzoic acid
chloride mixed with 200 g of toluene are added drop by
drop within an hour, and further stirring is carried out at
70 - 80C for one hour. After having filtered off the
triethylaminehydro chloride, washing with water follows to
effect neutrality and the toluene is withdrawn under reduced
pressure. As reaction product, 201 g of 3,5~dimethyl-
benzallylamide are obtained, which is sufficiently pure for
most purposes; it is a reddish-brown oil and corresponds to
98.5% of the theoretical yield. If further purification of
the product is desired, it can be distilled at a temperature
of I40 - 145C and a pressure o 0.05 Torr ~ 6.7 N/m2. The
distillate solidiies to a wax-like mass having a melting
point of 40 - 42C.
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Example 2
Preparation o~ 3,5-dime-thyl-benzoic acid propargylamide.
The preparation of the acid chloride is carried
out as in Example 1.
In the second step, 200 ml of toluene, 3 g (0.054 mol)
of propargylamine, and 5.5 g (0.054 mol) of triethylamine are
introduced into a three-neck flask equipped with a stirrer
and reflux cooler. Then, 9.2 g (0.054 mol) of 3,5-dimethyl-
benzoic chloride are added drop by drop and the mixture is
heated for two hours under reflux. The mixture is cooled
and filtered, and the filtrate washed with a total of 150 ml
of water. While washing, part of the product is already
precipitated, which is filtered off. The toluene phase is
concentrated to about 40 ml at which time a further amount
of product is obtained in the form of white crystals. After
drying in a drying chamber a yield of 7.5 g (73.6% of the
theoretical) of 3,5-dimethyl-benzoic acid propargylamide is
obtained.
Example 3
The herbicidal effectiveness of the products
according to the invention was tested using them once in a
hot house. In the described test, the seed grains of the
cultivated plants and the weeds were sown in a mineral-
containing soil of a field poor in humus, and lightly covered
with soil particles. I~mediately after the sowing, ln any
case before germination took place, the herbicides according
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to the invention were uniformly sprayed onto the veyetation-
free area in the form of spraying powders or emulsion con~
centrates.
Four weeks after the treatment, the plants were
finally tested for damage or total destruction, with control
- plants serving as a reference which grew up in the meanwhile
without having been treated.
Effectiveness in ~ with the use of 0.5 - 8 kg/ha
of effective agent in the pre-emergence process.
1 year
culti- ............ old off~
vàted -sugar wild.-meadow- - grade
~ k~/ha' mustard beet' oats` qrass foxtail.'~rain
.. 0~.'5~ '"'0 '' "'"'`'0'"''
3,5-Dimethyl- 1 0 0 100 100 75 95
Benzallylamide 2 0 0 100 100 90 100
.4 0 10 100 100 100 100
. 8 10 20 100 100 100 100
__ __ ~ _ .
: 0.5 0 0 70 90 75 60
3,5-Dimethyl- 1 0 0 85 100 95 80
benzoic-pro- 2 0 0 100 100 98 100
pargylamide 4 0 0 100 100 100 100
8 10 10 100 100 100 100
. ~ . ..
Comparison Exam~le 1
For comparison, tests were carried out with a
commercial herbicide, 'IKERB 50 Wl'*,~ which has been used
extensively for combating weeds and undesirable grass species,
on the one hand, and 3,5-dichloro~benzallylamide, on the
other hand, the criteria used being as described in Example 3.
Effectiveness in % with the use of 0.5 - 8 kg/ha
effective substance.
* Trade Mark
- 10
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1 year
kg/ha culti- old of-
Eff. vated sugar wild meadow grade
Aqent mustard beet oats q~ass foxtail qrain
- _ 0.5 10 65 `` 95 ~5 90 65
Propyzamide 1 40 85 100 100 100 75
(KERB 50 W)* 2 95 90 100 100 100 95
4 9~ 95 100 100 100 100
8 100 98 100 100 100 100
_ _ 0.5 10 10- ~7~ 77r~-----er--~
3,5-Dimethyl- 1 40 25 75 85 45 65
Benzallylamide 2 50 40 95 98 60 95
4 75 75 100 1(;)0 75 98
_ _ 8_ 9 Q _ 85 100 1(~ U~
Example 3 and Comparison Example 1 clearly show the
remarkably superior tolerance of cultivated plants (useful
plants) by treatment with the herbicides according to the
invention as compared to known herbicides, the activity
towards weeds and undesirable grasses being equal. The
comparison of 3,5-dichlorobenzallylamide with the compound
of the invention, 3,5-dimethylbenzallylamide,demonstrates
the critical importance of the 3,5-dimethyl position in the
herbicides behavior towards cultivated plants.
Example 4
In a further test series, the effectiveness of
the products of the invention when used in the pre-seeding
process with working into the soil. Herbicides are g~nerally
worked into the uppermost layer of the soil, if an improve-
ment of the effectiveness against the undesirable weeds and
the like can be accomplished~ for instance, in existing
dryness of the soil. In the above process, effec-tive agents
are evenly sprayed onto the vegetation-free 50il in the
form of e-mulsion concentrates or spraying powders.
*Trade Mark
~.
88Z
Immediately after the spraying, the agents are
worked into the uppermost soil surface by means of a rake
to a depth oE 2 - 3 cm. 24 hours thereafter, t.he sesdin~
of grains of cultivated plants and weeds is carried out into
the herbicide--treated soil surface. The final testing for
damage or total destruction of the plants takes place four
weeks after the ~reatment, with control plants serving as a,
- reference, which grew up in the meanwhile without having
been treated.
Activity in % with the use of effective ingredient
of 1 kg/ha in the pre-seeding process with mechanical work-in.
1 year
off- old
winter- sugar grade wild meadow fox- knot
kq/ha raFe beet qrain oats qrass tail weed
_ ~ . _ __
3,5-Dimethyl-
Benzallylamide 1 O O 98 100 100 98 100
. .
3,5-Dimethyl-
Benzoic- 1 O O100 100 100 9598
propargyl-
amide
Comparison Example 2
The compounds used for comparison are commercially
obtainable herbicides, which have been used for quite some
time for pest control in winter rape and sugar beets in a
pre-seeding process followed by work-in~ In addition,
3,5-dichlorobenzallylamide is used for comparison as in the
Comparison Example 1. Otherwise, the procedure was the same
as in Example 4.
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Effec-tiveness in ~ with -the use o 1 kg/ha o
effective agen-t in the pre-seeding 2rocess with work-in.
1 year
o~f~ old
winter- sugar grade wild nead~ fox- knot
.~ . kg/ha rape } t grain oats grass tail weed
Triflura-
lin 1 40 95 75 95 100100 95
(Elancolan)
Triallate
~Avadex BW) k 1 O 100 100 100 0
3,5-di-
chloro- .
benzallyl- 1 60 35 95 100 10070 85
amide __ _ _
Example 4 shows, taken together with Comparison
Example 2, the superior tolerance of the herbicides accord-
ing to the invention to cultivated plants, when compared
to conventional herbicides, the effect on weeds being equal
in both cases.
* Trade Mark
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