US3549750A - Alkoxy vinyl phosphono dithioates as nematocides - Google Patents

Description

United States Patent Q US. Cl. 424217 9 Claims ABSTRACT OF THE DISCLOSURE Compounds have the formula SR where R, is methyl, propyl, isopropyl or t-butyl and R and R are alkyl of 1 to 8 carbon atoms, phenyl, lower alkyl phenyl or chlorophenyl have nematocidal activity. Preferably R and R are lower alkyl. S, S-diisopropyl- 2-methoxyvinyl-phosphonodithioate is particularly effective.

BRIEF DESCRIPTION OF THE INVENTION This application is a continuation-in-part of application Ser. No. 612,101 filed Jan. 27, 1967, now Pat. No. 3,481,731. The entire disclosure of the parent application is thereby incorporated by reference.

In our parent application there is described the preparation of compounds having the formula where R, is lower alkyl, and R and R are alkyl of 1 to 8 carbon atoms, phenyl, lower alkyl phenyl or chloropheny R and R can be the same or different. The compounds in the parent application are disclosed as being good herbicides.

It has now been found that some of the compounds within this formula have good nematocide activity. Surprisingly, however, this is not true of all compounds of this general type. Thus if R is methyl, n-propyl, isopropyl or t-butyl the compounds exhibit nematocidal activity but if R is ethyl, n-butyl, isobutyl or isooctyl there is no nematocidal activity. Also if R is replaced by p-chlorophenyl there is no nematocidal activity. Preferably R and R are lower alkyl, most preferably 1 to 4 carbon atoms. The preferred compound is S,SFdiisopropyl-2-methoxyvinylphosphonodithioate. It is of interest that S,S-diisopropyl 2 isobutoxyvinylphosphonodithioate which was the most effective herbicide tested is ineffective as a nematocide despite its closeness in structure to S,S-diisopropyl 2 methoxyvinylphosphonodithioate.

As pointed out in the parent specification the compounds of the present invention within Formula I are readily prepared by reacting an alkyl vinyl ether with phosphorous pentachloride, preferably suspended in a solvent such as carbon tetrachloride to form the complexed 2-alkoxy 2 chloroethylphosphorustetrachloride. The complex is treated with two moles of sulfur dioxide. Dehydrohalogenation of the intermediate form in this reaction occurs simultaneously or upon removal of the phosphorus oxychloride-thionylchloride-solvent mixture to yield alkoxyvinylphosphonyldichloride. The alkoxyvinylice phosphonodithioates are formed by esterification of the alkoxyvinylphosphonyldichloride with a mercaptan in the presence of a tertiary amine, e.g. triethylarnine, tripropylamine, N,N-dimethylaniline, etc.

As alkyl vinyl ethers as starting materials there can be employed methyl vinyl ether, propyl vinyl ether, isopropyl vinyl ether and tert. butyl vinyl ether.

As mercaptans there can beused methyl mercaptan, ethyl mercaptan, propyl mercaptan, isopropyl mercaptan, butyl mercaptan, isobutyl mercaptan, hexyl mercaptan, octyl mercaptan, isooctyl mercaptan, Z-ethylhexyl mercaptan, thiophenol, p-methylthiophenol, 2-chlorothioph enol, 2,4-dichlorothiophenol, 4-butylthiophenol.

The most preferred compound tested as a nematocide was S,S-diisopropyl-2-methoxyvinylphosphonodithioate.

Other compounds useful as nematocides within the invention are S,S-diethyl-Z-methoxyvinylphosphonodithioate, S-S-dimethyl-Z-methoxyvinylphosphonodithioate, S,S-dipropyl 2-methoxyvinylphosphonodithioate, S,S-dibutyl-Z-methoxyvinylphosphonodithioate, S,S-diisobutyl-Z-methoxyvinylphosphonodithioate, S,S-di-sec. butyl-2-methoxyvinylphosphonodithioate, S,S-di-t-butyl-2-methoxyvinylphosphonodithioate, S-ethyl-S-isopropyl-2-methoxyvinylphosphonodithioate, S-methyl-S-propyl-Z-methoxyvinylphosphonodithioate, S,S-diamyl-2-methoxyvinylphosphonodithioate, S,S-diisoamyl-2-methoxyvinylphosphonodithioate, S,S-dioctyl-2-methoxyvinylphosphonodithioate, S,S-diphenyl-Z-methoxyvinylphosp honodithioate, S,S-di-p-tolyl-2-methoxyvinylphosphonodithioate, S,S-di-p-butylphenyl-Z-methoxyvirrylphosphonodithioate, S,S-di-p-chlorophenyl-Z-methoxyvinylphosphonodithioate, S-isopropyl-S-isobutyl-2-methoxyvinylphosphonodithioate, S,S-dimethyl-2-propoxyvinylphosphonodithioate, S,S-dimethyl-Z-isopropoxyvinylphosphonodithioate, S,S-dimethyl-2-t-butoxyvinylphosphonodithioate, S,S-diethyl-2-propoxyvinylphosphonodithioate, S,S-diethyl-Z-isopropoxyvinylphosphonodithioate, S,S-diethyl-2-t-butoxyvinylphosphonodithioate S,S-dipropyl-Z-propoxyvinylphosphonodithioate, S,S-dipropyl-Z-isopropoxyvinylphosphonodithioate, S,S-dipropyl-Z-t-butoxyvinylphosphonodithioate, S,S-diisopropyl-2-propoxyvinylphosphonodithioate, S,S-diisopropyl-2-isopropoxyvinylp hosphonodithioate, S,S-diisopropyl-2-t-butoxyvinylphosphonodithioate, S,S-dibutyl-2-propoxyvinylphosphonodithioate, S,S-dibutyl-2-isopropoxyvinylphosphonodithioate, S,S-dibutyl-2-t-butoxyvinylphosphonodithioate, S,S-diisobutyl-Z-propoxyvinylphosphonodithioate, S,S-diisobutyl-2-isopropoxyvinylphosphonodithioate, S,S-diisobutyl-Z-t-butoxyvinylphosphonodithioate.

The compounds employed in this invention are all high boiling liquids.

Unless otherwise indicated all parts and percentages are by weight.

Example 1 the solid phase and the formation of a clear solution.

The Z-methoxyvinyl phosphonyl dichloride was obtained by direct distillation of the reaction mixture.

Example 2 The procedure of Example 1 was repeated replacing the methyl vinyl ether by 0.5 mole of propyl vinyl ether to prepare 2-propoxyvinyl phosphonyl dichloride.

Example 3 The procedure of Example 1 was repeated replacing the methyl vinyl ether by 0.5 mole of isopropyl vinyl ether to prepare 2-isopropoxyvinyl phosphonyl dichloride.

Example 4 The procedure of Example 1 was repeated replacing the methyl vinyl ether by 0.5 mole of t-butyl vinyl ether to prepare 2-t-butoxyvinyl phosphonyl dichloride.

Example 5 17.5 grams (0.1 mole) of 2-(methoxy)vinyl phosphonyl dichloride was diluted with volumes of dry benzene. 12.5 grams (0.2 mole) of ethyl'mercaptan was then added. 20.2 grams (0.2 mole) of triethylamine was added to this stirring solution at such a dropwise rate to keep the exothermic reaction temperature at 3035 C. After the addition was completed, the reaction mixture was allowed to stir until room temperature was reached C.).

The reaction mixture was then washed with cold water. (If the water wash was acid, as occurred in some experiments, the benzene layer was extracted with 5% sodium bicarbonate solution. The benzene layer was then further washed until all washes were neutral.) The benzene layer was then dried over anhydrous sodium sulfate. The solvent was stripped in vacuo on a steam bath; and the resulting crude oil was distilled to obtain S,S-diethyl-Z-methoxyvinylphosphonodithioate (Compound 7374) as the product.

Example 6 13.5 grams (0.08 mole) of 2-(methoxy)vinyl phosphonyl dichloride was diluted with 10 volumes of dry benzene. 12.5 grams (0.16 mole) of isopropyl mercaptan was then added. 15.2 grams (0.15 mole) of triethylamine was added to this stirring solution at such a dropwise rate to keep the exothermic reaction temperature at -35 C. after the addition was completed, the reaction mixture was allowed to stir until room temperature was reached (25 C.).

The reaction mixture was then washed with cold water. (If the water wash was acid, as occurred in some experiments, the benzene layer was extracted with 5% sodium bicarbonate solution. The benzene layer was then further washed until all washes were neutral.) The benzene layer was then dried over anhydrous sodium sulfate. The solvent was stripped in vacuo on a steam bath; and the resulting crude oil was distilled to obtain S,S-diisopropyl-2-meth oxyvinylphosphonodithioate (Compound 7375) as the product.

Example 7 The procedure of Example 5 was repeated replacing the ethyl mercaptan by 0.2 mole of n-butyl mercaptan to obtain S,S dibutyl 2 methoxyvinylphosphonodithioate (Compound 7950) as the product.

Example 8 The procedure of Example 5 was repeated replacing the ethyl mercaptan by 0.2 mole of n-propyl mercaptan to obtain S,S dipropyl-2-methoxyvinyl phosphonodithioate (Compound 8132) as the product.

Example 9 The procedure of Example 5 was repeated replacing the 2-methoxyvinyl phosphonyl dichloride by 0.1 mole of 2-propoxyvinyl phosphonyl dichloride to obtain S,S-diethyl-2-propoxyvinylphosphonodithioate (Compound 7938) as the product.

4 Example 10 The procedure of Example 9 was repeated replacing the ethyl mercaptan by 0.2 mole n-propyl mercaptan to obtain S,S-dipropyl 2 propoxyvinylphosphonodithioate (Compound 7939) as the product.

Example 11 The procedure of Example 9 was repeated replacing the ethyl mercaptan by 0.2 mole of n-butyl mercaptan to obtain S,S-dibutyl-Z-propoxyvinylphosphonodithioate (Compound 7940) as the product.

Example 12 Example 14 The procedure of Example 12 was repeated replacing the ethyl mercaptan by 0.2 mole of n-butyl mercaptan to obtain S,S dibutyl-2-isopropoxyvinylphosphonodithioate (Compound 7956) as the product.

Example 15 The procedure of Example 5 was repeated replacing the 2-methoxyvinyl phosphonyl dichloride by 0.1 mole of 2-tbutoxyvinyl phosphonyl dichloride to obtain S,S-diethyl-2- t-butoxyvinylphosphonodithioate (Compound 7957) as the product.

Example 16 The procedure of Example 15 was repeated replacing the ethyl mercaptan by 0.2 mole of methyl mercaptan to obtain S,S dimethyl-2-t-butoxyvinylphosphonodithioate (Compound 8009) as the product.

Example 17 The procedure of Example 15 was repeated replacing the ethyl mercaptan by 0.2 mole of n-propyl mercaptan to obtain S,S dipropyl-2-t-butoxyvinylphosphonodithioate (Compound 7959) as the product.

The compounds have been used successfully with the parasitic nematode Meloidogyne spp. They are also effec tive nematocides for saprophytic nematodes such as Panagrellus spp. and Rhabditis spp.

The nematocides of the present invention can be used alone or they can be applied together with inert solids to form dusts, or can be dispersed in a suitable liquid dilute, e.g., organic solvents or water.

There can also be added surface active agents or wetting agents and/ or inert solids in the liquid formulations. In such case, the active ingredients can be from 0.01 to by weight of the entire composition.

As organic solvents there can be employed hydrocarbons, e.g., benzene, toluene, xylene, kerosene, diesel fuel, fuel oil and petroleum naphtha, ketones such as acetone, methyl ethyl ketone and cyclohexanone, chlorinated hydrocarbons such as carbon tetrachloride, chloroform, trichloroethylene, and perchloroethylene, esters such as ethyl acetate, amyl acetate and butyl acetate, ethers, e.g. ethylene glycol monomethyl ether and diethylene glycol monomethyl ether, alcohols, e.g. methanol, ethanol, isopropanol, amyl alcohol, ethylene glycol, propylene glycol, butyl carbitol acetate and glycerine. Mixtures of water and organic solvents, either as solutions or emulsions, can be employed.

The novel nematocides can also be applied as aerosols, e.g. by dispersing them in air by means of a compressed gas such as dichlorodifluoromethane or trichlorofluoromethane and other Freons and Genetrons, for example.

The pesticides of the present invention can also be applied with adjuvants or carriers such as talc, pyrophyllite, synthetic fine silica, attapulgus clay, kieselguhr, chalk, diatomaceous earth, lime, calcium carbonate, bentonite, fullers earth, cottonseed hulls, wheat flour, soybean flour, pumice, tripoli, wood flour, walnut shell flour, redwood in a water-agar medium in the presence of tomato roots at room temperature.

In Table 1 the same scale is employed with 0 indicating no control (severe knotting) and indicating complete control. The compounds tested had the formula flour and lignin. O SR2 As stated, it is frequently desirable to incorporate a Q/ surface active agent in the pesticidal compositions of the 10 present invention. Such surface active or wetting agents are advantageously employed in both the solid and liquid compositions. The surface active agent can be anionic, cationic or nonionic in character. R and R were identical.

TABLE I Average root knot indices at concentrations of 200 20 12 6 3 R1 R2, R3 p.p.n1. ppm. ppm. p.p.m ppm. ppm

CH3 n-o Hi Calls CH3 C2115 11-C3H7 1 Phytotoxie.

Typical classes of surface active agents include alkyl sulfonate salts, alkylaryl sulfonate salts, alkylaryl polyether alcohols, fatty acid esters of polyhydric alcohols and the alkylene oxide addition products of such esters, and addition products of long chain mercaptans and alkylene oxides. Typical examples of such surface active agents include the sodium alkylbenzene sulfonates having 10 to 18 carbon atoms in the alkyl group, alkylphenol ethylene oxide condensation products, e.g. p-isooctylphenol condensed with 10 ethylene oxide units, soaps, e.g. sodium stearate and potassium oleate, sodium salt of propylnaphthalene sulfonic acid, di (2-ethylhexyl) ester of sodium sulfosuccinie acid, sodium lauryl sulfate, sodium decane sulfonate, sodium salt of the sulfonated monoglyceride of cocoanut fatty acids, sorbitan sesquioleate, lauryl trimethyl ammonium chloride, octadecyl trimethyl ammonium chloride, polyethylene glycol lauryl ether, polyethylene glycol esters of fatty acids and rosin acids, e.g. Ethofat 7 and 13, sodium N-methyl-N-oleyl taurate, Turkey Red Oil, sodium dibutyl naphthalene sulfonate, sodium lignin sulfonate, polyethylene glycol stearate, sodium dodecylbenzene sulfonate, tertiary dodecyl polyethylene glycol thioether (Nonionic 218), long chain ethylene oxide-propylene oxide condensation products, e.g. Pluronic 61 (molecular weight 1000), polyethylene glycol ester of tall oil acids, sodium octyl phenoxyethoxyethyl sulfate, tris (polyoxyethylene) sorbitan monostearate (Tween 60), and sodium dihexyl sulfosuccinate.

The parasitic nematode test was carried out using Meloidognye spp. with a 10 day contact test carried out It is clear from the table that the particular grouping chosen for R is critical in order to obtain nematocidal activity. Of the compounds tested S,S-diisopropyl-2-methoxyvinylphosphonodithioate (Compound 7375) had by far the best activity as a nematocide While S,S-dipropyl-2- t-butoxyvinylphosphonodithioate (Compound 7959) was next best.

When the nematocides of the present invention are applied after emergence of the desired crop plants they, of course, should be used in an amount effective to kill the nematodes but insufficient to act as a herbicide.

What is claimed is:

1. A process of killing nematodes comprising applying to the nematodes a nematocidally effective amount of a compound having the formula where R is methyl, propyl, isopropyl or t-butyl and R and R are alkyl of 1 to 8 carbon atoms, phenyl, lower alkyl phenyl or chlorophenyl.

2. A process according to claim 1 wherein R and R are lower alkyl.

3. A process according to claim 2 wherein R is methyl.

4. A process according to claim 3 wherein R and R are both isopropyl.

5. A process according to claim 2 wherein R is t-butyl.

6. A process according to claim 2 wherein the nematodes are parasitic nematodes.

7. A process according to claim 6 wherein R is methyl.

8. A process according to claim 7 wherein R and R are both isopropyl.

References Cited UNITED STATES PATENTS 3,047,605 7/1962 Schrader 424--210 3,416,912 12/1968 Regel et a1. 7182 ALBERT T. MEYERS, Primary Examiner V. D. TURNER, Assistant Examiner US. Cl. X.R.

9. A process according to claim 6 wherein R is t-butyl. 10 424219