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DESCRIPTION OF THE PRIOR ART
Various methanimidamides (formamidines) are taught in the prior art. For
example, U.S. Pat. Nos. 3,462,537, 3,484,526 and 3,502,720 teach
N-(substituted and unsubstituted phenyl)N',N'-dimethyl (or N'-methyl)
formamidines and their use as insecticides. In addition, Belgium Pat. No.
866,194 (German Patent Application No. 2,717,437) discloses the instant
N-(4-chloro-2-methylphenyl)-N'-hydroxy methanimidamide and its use as an
insecticide.
SUMMARY OF THE INVENTION
The present invention is directed to the
N-(4-chloro-2-methylphenyl)-N'-hydroxy methanimidamide which corresponds
to the formula
##STR1##
and its use as an insecticide for the control of various insects.
The compound of the present invention can be prepared by a variety of
methods. For example, it can be prepared by the reaction of one molecular
equivalent of N,N-dimethyl-N'-(4-chloro-2-methylphenyl)methanimidamide
with from 1 to 10 molecular equivalents of one of
hydroxylamine:hydrochloride.
The reaction can be characterized as follows:
##STR2##
wherein M is sodium, potassium, lithium or cesium. (no attempt has been
made to present a balanced equation)
In carrying out this reaction,
N,N-dimethyl-N'-(4-chloro-2-methylphenyl)methanimidamide is mixed with the
hydroxylamine:hydrochloride in the presence of an alkali metal methoxide
solution containing excess methanol. The mixture is stirred at room
temperature for from about 3 to about 20 hours. The reaction product is
recovered by filtration and the filtrate is concentrated under reduced
pressure to recover any additional product contained therein. The residue
from the concentration step and the filter cake are combined and suspended
in water, collected by filtration, water washed and the product recovered
after being further purified by recrystallization from ethanol or aqueous
ethanol.
Alternatively, the compound can be prepared by reacting one molecular
equivalent of N-(4-chloro-2-methylphenyl)methanimidic acid; ethyl ester
with an excess of hydroxylamine:hydrochloride and an alkali metal
hydroxide in the presence of methanol as the reaction medium. The mixture
is reacted, with agitation, at room temperature and the reaction is
usually complete in from about 3 to about 20 hours. The solid product
which forms is collected by filtration and usually additional product can
be obtained by concentration of the filtrate under reduced pressure and
the addition of the residue to the filter cake. The combined solids are
triturated with water, collected by filtration, washed with water and the
recovered product further purified by recrystallization from ethanol or
aqueous ethanol.
This reaction can be characterized as follows:
DESCRIPTION OF SOME PREFERRED EMBODIMENTS
Example I--N-(4-Chloro-2-methylphenyl)-N'-hydroxymethanimidamide
To a sodium methoxide solution prepared by dissolving 19 grams of sodium
metal in 250 milliliters of methanol was added 56 grams of
hydroxylamine:hydrochloride in 300 milliliters of methanol. To the
resulting mixture was added 98 grams (0.5 mole) of
N,N-dimethyl-N'-(4-chloro-2-methylphenyl)methanimidamide. The mixture was
stirred at room temperature for 18 hours. The solid reaction product was
recovered by filtration and the filtrate concentrated by evaporation under
reduced pressure. The residue and the solid reaction product (filter cake)
were suspended in water, collected by filtration, water washed and
recrystallized from ethanol. The
N-(4-chloro-2-methylphenyl)-N'-hydroxymethanimidamide product was
recovered in a yield of 81.7 grams (89% of theoretical) and melted at
171.degree.-171.5.degree. C.
The new compound of the present invention possess excellent insecticidal
and acaracidal properties and is very suitable in the control of chewing
and sucking insects for the protection of plants and stored goods. The
compound penetrates into the tissues of plants and is highly effective as
a contact and stomach poison insecticide. Due to its low toxicity to
warm-blooded animals, it is also suitable for the control of ecto- and
endo-parasites on and in animals.
The compound of the present invention can be employed during any stage of
the insect development, i.e. adult, larvae or egg.
In its use as an insecticide, an insecticidal amount of the compound per se
or a composition incorporating an insecticidal amount of the compound is
used as the toxicant for contact with the pest insect or its habitat. The
insecticidal amount, of course, is that quantity which elicits toxic
mortality among the treated pests. Generally, such insecticidal response
results by contacting the target pests or their habitat with a composition
containing from 0.00001 to 99 or more percent of the active compound in
the total composition. Good results are achieved upon contact with a
composition containing about 1000 parts of the active compound per million
by weight.
Suitable compositions include those which are in the form of liquid
solutions, liquid emulsifiable concentrates, and dust or granular
preparations. Such can be further diluted as and where appropriate with
conventional diluents.
Liquid compositions containing the active compound are prepared by
dissolving the active compound in a suitable inert organic solvent such as
acetone, toluene, xylene, methylene chloride, chlorobenzene, ethyl ether
or petroleum distillates or by dispersing the active compound in water
with or without the aid of a suitable surface acting dispersing agent such
as can be provided by ionic or nonionic dispersing and emulsifying agents.
The aqueous compositions may contain one or more water-immiscible solvents
for the toxicants. In such compositions, the carrier comprises an aqueous
emulsion, that is, a mixture of water-immiscible solvent, emulsifying
agent and water. The choice of dispersing and emulsifying agents and the
amounts thereof employed is dictated by the nature of the composition type
and by the ability of the agent to facilitate the dispersion of the active
toxicant compound in the aqueous carrier to produce the desired
composition. Dispersing and emulsifying agents which may be employed in
the compositions include the condensation products of alkylene oxides with
phenols and organic acids, alkylarylsulfonates, polyoxyethylene
derivatives or sorbitan esters, complex ether alcohols, mahogany soaps,
and the like. In such compositions, the surface active agents are usually
employed in the amount of from 1 to 20 percent by weight of the combined
weight of the surface active agent and the active compound.
In the preparation of dust compositions, the active compound is dispersed
in and on a finely divided inert sold such as talcum, chalk, gypsum, and
the like. In such operations, the carriers are mechanically ground with
the compounds or wet with a volatile organic solvent solution thereof.
Similarly dust compositions containing the compound may be prepared from
bentonite, fuller's earth, attapulgite, and other clays. Depending upon
the proportions of ingredients, these dust compositions may be employed as
concentrates and subsequently diluted with additional solid surface acting
dispersing agent or with talc, chalk, or gypsum and the like to obtain a
desired amount of active agent in a composition adapted to be applied for
insect control. Also, such concentrate dust compositions may be dispersed
in water with or without the aid of a dispersing agent to form spray
mixtures.
Granular formulations are conveniently prepared by impregnation, such as
through simple mechanical mixing of the active compound in a presized
carrier, usually of the type herebefore set forth.
In practice, the active compound is distributed so as to provide contact of
the target insect with toxic amounts of the active compound. Such contact
can be achieved through direct contact of the active compound with the
target insect or by more indirect means such as by application to its food
and/or habitat. Thus, for example, the active compound or a composition
thereof can be spread throughout the environs of the target host so as to
both provide direct and indirect contact thereof or bait compositions
incorporating a toxic amount of the active compound or composition thereof
can be readily prepared and strategically located so as to provide
ultimate contact of the host species therewith.
The following examples serve to further typify the nature of the present
invention and are given solely for the purpose of illustration.
Example II
25 Parts by weight of
N-(4-chloro-2-methylphenyl)-N'-hydroxymethanimidamide, 60 parts of
fuller's earth, 10 parts of diatomaceous earth, 3 parts of an alkyl aryl
sulfonate (Naccanol NR) and 2 parts of a polymerized sodium salt of a
substituted benzoid alkyl sulfonic acid (Daxad No. 27) are mechanically
mixed and ground together to prepare a concentrate composition in the form
of a wettable powder.
Similarly, 25 parts by weight of
N-(4-chloro-2-methylphenyl)-N'-hydroxymethanimidamide, 65 parts xylene and
10 parts of a dimeric alkylated aryl polyether alcohol (Triton X-155), are
mechanically mixed together to prepare a liquid emulsifiable concentrate
composition.
In a like manner, 6 parts by weight of the
N-(4-chloro-2-methylphenyl)-N'-hydroxy methanimidamide, 2 parts of
Naccanol NR, 2 parts of Daxad No. 27, and 200 parts of water are
ballmilled together to prepare a concentrate composition in the form of a
water-dispersible liquid.
Example III
1 Part of N-(4-chloro-2-methylphenyl)-N'-hydroxy methanimidamide is mixed
with 99 parts of purified kerosene to obtain an oil preparation having an
active ingredient concentration of 1 percent. In application, the
composition can be atomized or sprayed as is.
The concentrate compositions may be further diluted in their concentrate
state and/or dispersed in water to prepare aqueous compositions which have
desirable wetting and penetrating properties. These compositions are
adapted to be employed to treat target insects and distribute the active
compound in insecticidal concentrations.
Example IV
In this operation, an aqueous dispersion was prepared by admixing a
predetermined amount of N-(4-chloro-2-methylphenyl)-N'-hydroxy
methanimidamide dissolved in a suitable inert solvent, with a
predetermined quantity of water and a predetermined amount of a surfactant
to give aqueous dispersions containing varying predetermined amounts of
the compound as the sole active toxicant. Separate 3 inch discs cut from
tobacco plant leaves were thoroughly wetted by briefly dipping into one of
the dispersions and the wetted leaves placed in an open Petri dish and
permitted to dry. After the leaves were dry, 5 live tobacco budworm
larvae, approximately late 2nd instar, were placed in each Petri dish. In
identical operations, 5 like live tobacco budworm larvae were placed in
control Petri dishes, the leaf therein having been wetted with a solution
containing only water and surfactant. The dishes were maintained under
moist conditions at about 80.degree. F., conducive for the growth of the
tobacco budworm larvae, for a period of about 2 days. At the end of the
2-day period, the dishes were examined to determine the minimum
concentration in parts of the active compound per million parts of the
ultimate dispersion necessary to give at least a 95 percent kill and
control of the tobacco budworm larvae. The results of this examination are
set forth below in Table I.
TABLE I
______________________________________
Minimum Concentration in
PPM of active compound in
Active dispersion to give LC.sub.95
Compound for tobacco budworm larvae
______________________________________
N-(4-chloro-2-methylphenyl)-
N'-hydroxy methanimidamide
100
Control No Control
______________________________________
Example V
Aqueous dispersions were prepared by admixing a predetermined amount of
N-(4-chloro-2-methylphenyl)-N'-hydroxy methanimidamide dissolved in a
suitable inert solvent, with a predetermined quantity of water and a
predetermined amount of a surfactant to give aqueous dispersions
containing varying predetermined amounts of the compound as the sole
toxicant. Tobacco budworm adults were placed on separate tobacco seedlings
and left on for one day. This permitted the budworms to lay eggs. One
group of the seedlings was sprayed with one of the dispersions to run off.
In like manner another group of the seedlings was sprayed to run off with
a solution containing only water and surfactant. The seedlings were
maintained under conditions conducive to the growth of the seedlings and
tobacco budworm. After a period of two days, the seedlings were examined
to determine the minimum concentration in parts of the active compound per
million parts of the ultimate dispersions necessary to cause a failure to
hatch of at least 90 percent of the tobacco budworm eggs. The results of
this examination are set forth below in Table II.
TABLE II
______________________________________
Minimum Concentration in
PPM of active compound in
Active dispersion to give LC.sub.90
Compound for tobacco budworm eggs
______________________________________
N-(4-chloro-2-methylphenyl)-
N'-hydroxy methanimidamide
22
Control No Control
______________________________________
Example VI
Aqueous dispersions were prepared by admixing a predetermined amount of
N-(4-chloro-2-methylphenyl)-N'-hydroxy methanimidamide dissolved in a
suitable inert solvent, with a predetermined quanity of water and a
predetermined amount of a surfactant to give aqueous dispersions
containing varying predetermined amounts of the compound as the sole
toxicant. Separate cotton plants were infested with approximately 100
two-spotted spider mites and the plants dipped into one of the
dispersions. In a like manner, approximately 100 two-spotted spider mites
were placed on control plants and the plants sprayed to run off with a
solution containing only water and surfactant. The plants were maintained
under conditions conducive to the growth of the plants and mites. After a
period of five days, the plants were examined to determine the minimum
concentration in parts of the active compound per million parts of the
ultimate dispersion necessary to give at least 95 percent kill and control
of the two-spotted spider mites. The results of this examination are set
forth below in Table III.
TABLE III
______________________________________
Minimum Concentration in
PPM of active compound in
Active dispersion to give LC.sub.95
Compound for two-spotted spider mites
______________________________________
N-(4-chloro-2-methylphenyl)-
N'-hydroxy methanimidamide
400
Control No Control
______________________________________
In another operation, the compound of the present invention was found to
give 100 percent kill and control of American dog tick when applied
thereto in an aqueous dispersion containing the compound as the sole
toxicant, at 250 parts of the compound per million parts of the ultimate
dispersion.
In another operation, the above compound was found to give at least 50
percent kill and control of the cabbage looper when applied to the habitat
thereof in an aqueous dispersion, as the sole toxicant, at 400 parts of
the compound per million parts of the ultimate dispersion. In another
operation, the above compound was found to give 100 percent kill and
control of hornflies when applied thereto in an aqueous dispersion
containing the compound, as the sole toxicant, at 1 part of the compound
per million parts of the ultimate dispersion.
In another representative operation, the compound of the present invention
was found to give at least 50 percent kill and control of codling moth
when applied to either the eggs or larvae of the insect in an aqueous
dispersion, as the sole toxicant, at 100 parts of the compound per million
parts of the ultimate dispersion.
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