Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
llSlV64
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01 SUBSTITUTED OXADIAZOLES AND THEIR USE
AS WIRE WORM AND FLEA BEETLE INSECTICIDES
AND GRUB INSECTICIDES
BACRGROUND OF THE INVENTION
The present invention relates to certain
oxadiazole derivatives and their use as wire worm and flea
beetle insecticides and grub insecticides.
British Patent 1,213,707 discloses insecticidal
compounds of the general formula
R10 Xl
~P--X2--A--~-R3
wherein Xl and X2, which may be the same or different,
each represents an oxygen or sulfur atom; A represents an
alkylene group; Rl represents an alkyl group, R2 repre-
sents an alkyl or alkoxy group; and R3 represents a
hydrogen atom or an optionally substituted carbamoyl or
amino group. A particular species disclosed in the
British Patent at Table 2, 9th compound from the top, is
3-(diethoxyphosphinothioylthiomethyl)-5-methyl-1,2,4-
oxadiazole.
The examples of the British Patent show testing
of certain of the compounds for insecticidal activity on
adult houseflies; mosquito larvae, diamond back moth
larvae, aphids and adult mustard beetles; red spider
mites; and white butterfly larvae. None of these tests
involved application and use of the insecticide in the
soil habitat of the insects.
U.S. Patent 4,028,377 discloses insecticidal
compounds of the general formula
1151064
01
O -- N O/OR3
Rl~ -CH3-S-p~
O S SR2
wherein Rl represents hydrogen, unsubstituted alkyl,
benzyl or phenyl, R2 represents methyl or ethyl, and R3
represents unsubstituted Cl-C7 alkyl optionally inter-
rupted by oxygen or represents C3-C4 alkenyl.
The examples of the 4,028,377 patent show
testing of certain of the compounds for insecticidal
activity on ticks in cotton wool; larvae of ticks; mites;
and on root-gall-nematodes in soil. In the latter test,
the soil infested with the root-gall-nematocides was
treated with the compounds to be tested and then tomato
seedlings were planted either immediately after the soil
preparation or after 8 days waiting.
British Patent 1,261,158 discloses compounds of
the general formula
Rl O~X
~P-S-A-r~-- f( Y ) n
R2
The first compound disclosed in Table I of British Patent
1,261,158 is 5-(diethoxyphosphinothioylthiomethyl)-3-
methylisoxazole. The compounds of the examples of British
Patent 1,261,158 were tested for insecticidal effective-
ness on flies, mosquito larvae, moth larvae, mustard
beetles, aphids, spider mites and butterfly larvae.
U.S. Patent 3,432,519 discloses various oxadia-
zoles with phosphate groups in the 5-position on the
1151064
--3--
01 oxadiazole ring. Example 2 discloses 3-methyl-5-chloro-
methyl-1,2,4-oxadiazole. U.S. Patent 3,432,519 in
Example 4 discloses that the last-named compound is used
to destroy green flies, red spiders and caterpillars.
05 As described in the Ortho Seed Treater Manual
copyrig~ 197~, Chevron Chemical Company, page 27, wire
worms/have been controlled with a formulation comprising a
mixture of Lindane (gamma isomer of benzene hexachloride)
and Captan (n-l(trichloromethyl)thio]-4-cyclohexene-1,2-
dicarboximide ) .
SUMMARY OF THE INVENTION
According to the present invention, there is
provided a method for killing wire worms and/or flea
beetles which comprises applying to the soil habitat of
the wire worms and/or flea beetles an insecticidally
effective amount of a compound of the formula
N
Rl_c ~ -CH2XP-ZR2 (I)
wherein Rl, R2 and R3 are alkyl of 1 to 4 carbon atoms;
and X, Y, Z and V are sulfur or oxygen.
Preferred compounds for use in this method
include those wherein R2 and R3 are ethyl and, more
preferably, wherein the compound is further defined in
that Y is sulfur and Z and V are oxygen. Most preferably,
the compound used is one wherein the compound is still
further defined in that Rl is methyl and X is sulfur.
According to another alternative embodiment of
the present invention there is provided a wire worm and/or
a flea beetle insecticidal composition comprising a wire
worm- and/or a flea beetle-insecticidally effective amount
115~064
01 of a compound of the formula I, wherein Rl, R2 and R3 are
alkyl of 1 to 4 carbon atoms; and X, Y, Z and V are sulfur
or oxygen; and a biologically inert carrier. Preferably,
the compound used in this embodiment of the present
05 invention is 3-methyl-5-(diethoxyphosphorothioylthio-
methyl)-1,2,4-oxadiazole.
- The term "wire worm" is used herein to include
the larvae of click beetles and also to include "False
wire wormsn. Click beetles are in the family Ela'eridae
and the following genera in the Elateridae family are
particularly preferred genera for the insecticidal method
of the present invention: Melantus, Ctenicera, Conoderus,
Limonius, Horistonotus, and Agriotes. False wire worms
are in the family Tenibrionidae. The following genera in
the Tenibrionidae family are particularly preferred genera
against which the insecticidal method of the present
invention is used: Eleodes, Blapstinus, and Embaphion.
The term "flea beetle" is used herein to mean
the larvae of flea beetles of the genera Chrysomelidae.
The following genera in the Chrysomelidae family are
particularly preferred genera against which the insecti-
cidal method of the present invention is used:
Chaetocnema, Epitrix, Phvllotreta, and Systena.
According to the present invention, there is also
provided a method for killing grubs which comprises
applying to the soil habitat of the grubs an insecti-
cidally effective amount of a compound of the formula I.
Preferred compounds for use in this embodiment
include those wherein R2 and R3 are ethyl and, more
preferably, wherein the compound is further defined in
that Y is sulfur and Z and V are oxygen. Most preferably,
the compound used is one wherein the compound is still
further defined in that Rl is methyl and X is sulfur.
1151064
01 According to another alternative embodiment of
the present invention, there is provided a grubs insecti-
cidal composition comprising a grub-insecticidally
effective amount of a compound of the formula I, wherein
05 Rl, R2 and R3 are alkyl of 1 to 4 carbon atoms; and X, Y,
Z and V are sulfur or oxygen; and a biologically inert
carrier. Preferably, the compound used in this embodiment
of the present invention is 3-methyl-5-(diethoxyphosphoro-
thioylthiomethyl)-1,2,4-oxadiazole.
The term ~grub" is used herein to mean the
larvae of Scarab beetles. Scarab beetles are the family
Scarabeidae. The following genera in the Scarabeidae
family are particularly preferred genera against which the
insecticidal method of the present invention is used; `
Popillia, Lachnostera, Premnotrvpes, Costelytra, Phyllo-
phaga, Heteronychus and Diaprepes.
The compounds of the present invention may be
prepared by subjecting 3-alkyl-5-chloromethyl-1,2,4-
oxadiazoles (II) to a phosphorylation reaction.
The 3-alkyl-5-chloromethyl-1,2,4-oxadiazoles
tII) were prepared by condensing the appropriate alkyl-
amidoximes (obtained from nitriles -- see Chem. Revs. 61
155 (1961) with chloroacetyl chloride.
N-OH O N O
Rl ~ + Cl-C-CH2-Cl- ~Rl- ~ ~ -CH2-Cl (II)
NH2
The 3-alkyl-5-chloromethyl-1,2,4-oxadiazoles
were phosphorylated with phosphate salts of the general
formula (III) to give (I) above:
Y M=K~Na~ and NH
M~X-P-ZRl X,Y = S and O
VR3 V,Z = S, O and NH
1151064
01 This last reaction can be carried out in a
number of solvents, e.g., acetone, acetonitrile, ether,
methanol, benzene, etc. Preferably, equimolar amounts of
reactants are employed, although a small excess of either
OS may be employed. Either reactant may be added to the
other reactant in the solvent; however, it is preferred to
add the solid phosphate salt to a solution of the 3-alkyl-
5-chloromethyloxadiazole. The addition is carried out at
temperatures in the range of 15-30C. Upon completion of
addition of the salt, the temperature of the reaction is
raised, preferably to the reflux temperature.
The reaction is generally complete in 1-5
hours. At completion of the reaction, the product
reaction mixture is filtered to remove any insoluble
salts. The filtrate is then stripped of solvent under
reduced pressure to give crude 3-alkyl-5-(dialkoxyphos-
phorothioylthiomethyl)-1,2,4-oxadiazole. The crude
material can be purified by column chromatography (silica
gel) and eluting with hydrocarbons and chlorinated
hydrocarbons.
Example 1 -- Preparation Methods
(a) Acetamidoxime -- Acetonitrile was added to
a previously stirred solution of 0.55 mol hydroxylamine
hydrochloride and 0.55 mol anhydrous sodium carbonate in
750 ml of absolute ethanol. This mixture was stirred for
0.5 hour at room temperature and then refluxed at 55-70C
for 24 hours. The reaction was cooled and filtered, the
solid residue slurried in warm acetone and refiltered, the
filtrates were combined and concentrated to an oil under
reduced pressure. The oil was again taken up in acetone-
ether to rid the system of dissolved inorganic salts. The
acetone-ether filtrate was concentrated under reduced
pressure, the oil was then triturated with ether-hexane
leaving a white solid. Infrared (IR) and nuclear magnetic
- 35
1151064
-7-
01 resonance (NMR) elemental analysis indicated the
acetamidoxime (m.p. 128-133C).
(b) 3-Methyl-5-Chloromethyl-1,2,4-Oxadiazole --
Acetamidoxime (14.1 g) was placed in 200 ml of benzene in
05 a 3-necked, round-bottom flas~ equipped with a mechanical
stirrer, condenser and dropping funnel charged with 23 9
of chloroacetyl chloride. The benzene slurry was
increased in temperature to near reflux, and the chloro-
acetyl chloride was added dropwise to the refluxing
mixture. A Dean-Stark trap was added and refluxing
continued for 3 hours. The reaction mixture was cooled
and 100 ml benzene added, washed (3x125 ml) with water,
dried with anhydrous MgSO4, and solvent removed under
reduced pressure, leaving the desired product as an amber
liquid (confirmed by IR, NMR and elemental analysis).
(c~ 3-MethYl-5-(diethoxyphosphorothioylthio-
methyl)-1,2,4-oxadiazole -- 3-methyl-5-chloromethyl-1,2,4-
oxadiazole (0.04 mol) was dissolved in acetone and
ammonium O,O-diethyldithiophosphate (0.04 mol) was added
with stirring in several portions. The reaction was then
refluxed for 3 hours, cooled and filtered. The solvent
was removed under reduced pressure leaving an amber oil
which was chromatographed (silica gel) and eluted with
hexane: methylene chloride (80%). The phosphate was
obtained as an almost colorless oil.
Example 2 -- Compound Testing Against Wire Worms
and Flea Beetles Larvae
A granule containing 10% by weight of 3-methyl-
5-(diethoxyphosphinothioylthiomethyl)-1,2,4-oxadiazole
(the test compound) was distributed in the test field by a
broadcast method. The field was then disced to incorpo-
rate the granules to a depth of 4 to 5 inches in the
soil. Dosage was at 3, 2, and 1 pound test compound per
acre.
llS10~4
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01 Next Julian Sweet potatoes were transplanted ,
into the treated plots known tG be infested with wire
worms (Conoderus vespertinus and C. auritus), and flea
beetles larvae (SYstena elongata). Four months later, the
05 sweet potatoes were harvested and were graded for number
of roots damaged and/or scarred by wire worms and flea
beetle larvae. The results are given in Table I.
2S
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Examples 3 -- Compound Testing Against Grubs
Two tests were carried out using 3-methyl-5(diethyoxyphosphino-
thioylthiomethyl)-1,2,4-oxadiazole (test compound) to determine effective-
ness for the control of grass grubs. In the first test, the test compound
was applied directly to the insect, whereas in the second test, soil was
treated with the test compound and then the insects were introduced into that
soil.
Topical Application
Third Instar Grassgrubs (Costelytra zealandica) having an average
weight of 100.5 mg were contacted with the indicated amount of the test com-
pound and were then checked periodically for effects. The test concentration
and results are given in Table II.
TABLE II
Dosage Percent Affected
Micrograms/insect 2 hours 3 days 7 days
100 100 100
l 93 79 75
0.1 7 7 7
These results show that at 10 microgram/insect there is 100% con-
trol, and at 1 microgram/insect there is still a 75% control.Soil Treatment
_
~ orotin silt loam, having 32% moisture content, was treated with an
insecticide, either Lindan insecticide or the test compound, to give an aver-
age actice concentration of 14 ppm in the soil (on a weight to weight basis).
Next 86 mm petri dishes were each firmly packed with 85 grams of this treated
soil. Then 10 freshly collected Grassgrub beetles were placed in each petri
dish
-10-
,
.
llS1064
01 which was then covered with an inverted petri dish to
prevent es¢ape.
All of the beetles buried themselves in the soil
within 10 minutes. Affected beetles subsequently re-
os emerged. The number remaining on top of the soil at
several time intervals were recorded. After 24 hours of
exposure to the treated soil, all beetles were removed and
placed onto untreated soil in covered dishes. The number
of beetles remaining above the soil were again recorded.
These results are given in Table III.
The results in Table III show that the test
compound has high insecticidal activity against the
Grassgrub.
1151064
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