CA1151064A - Substituted oxadiazoles and their use as wire worm and flea beetle insecticides and grub insecticides - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
"SUBSTITUTED OXADIAZOLES AND THEIR USE AS
WIRE WORM AND FLEA BEETLE INSECTICIDES AND
GRUB INSECTICIDES"
A method for killing wire worms and flea beetles and grubs which comprises applying to the soil habitat of the wire worms and flea beetles and grubs an insecticidally effective amount of a compound of the formula

Description

llSlV64 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 Rl~ -CH3-S-p~

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 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 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.

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) 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

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 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 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.

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1~510~i4 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 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 , .

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.

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Claims (8)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method for killing wire worms or flea beetles which comprises applying to the soil habitat of the wire worms or flea beetles an insecticidally effective amount of a compound of the formula wherein R1, R2 and R3 are alkyl of 1 to 4 carbon atoms;
and X, Y, Z and V are sulfur or oxygen.

2. A method in accordance with Claim 1 wherein R2 and R3 are ethyl.

3. A method in accordance with Claim 2 wherein Y is sulfur and Z and V are oxygen.

4. A method in accordance with Claim 3 wherein R1 is methyl and X is sulfur.

5. A method for killing grubs which comprises applying to the soil habitat of the grubs an insectici-dally effective amount of a compound of the formula .

wherein R1, R2 and R3 are alkyl of 1 to 4 carbon atoms;
and X, Y, Z and V are sulfur or oxygen.

6. A method in accordance with Claim 5 wherein R2 and R3 are ethyl.

7. A method in accordance with Claim 6 wherein Y is sulfur and Z and V are oxygen.

8. A method in accordance with Claim 7 wherein R1 is methyl and X is sulfur.